Mobile App Security Audit Cost (2026): Complete Pricing, Budgeting, Compliance & ROI Guide

Mobile apps are now central to almost every business operation, encompassing anything from a customer’s account and transaction records, an employee’s sensitive information, to a patient’s health record. With increasing connectivity within mobile ecosystems, powered by APIs, cloud services, third-party integrated applications, and artificial intelligence functionalities, mobile app security threats are only continuing to increase.

Security is a requirement of compliance, as businesses need to comply with  UK GDPR, PCI DSS, FCA, ISO 27001, the NHS Data Security & Protection Toolkit, and many more.

Mobile application security audit within the UK can cost from £4,500 to £50,000. However, the actual costs can vary significantly depending on a number of factors. Let’s break down these factors in detail that influence the mobile app security audit pricing in the UK and explore what businesses should expect to budget for different types of apps and security requirements. 

What is a mobile app security audit?

Mobile app security auditing is a systematic examination process used to identify vulnerabilities, weaknesses in the security of mobile applications and supporting infrastructure, and instances where applications are non-compliant. These risks often present themselves as those that could potentially put sensitive data at risk, negatively affect service continuity, impact user accounts, or violate regulations.

Security audits not only identify vulnerabilities and instances where regulations are non-compliant through methods such as automated scans, but additionally through a comprehensive review, analyse the architecture, source code of the application itself, APIs, and the other layers of the mobile application’s structure. Independent security auditors analyse not just the application on the handset, but also data streams, authentication models, cloud environments, back-end systems, and any third-party systems connected to it.

The security audit will ultimately give the business an independent perspective on security vulnerabilities and will help to prioritise what needs attention before they can be exploited by threats.

What is covered in a security audit?

The depth and breadth of the security audit depend on the complexity of the app and regulatory considerations. The majority of these assessments test different parts of the tech stack to find the security vulnerabilities and also test security controls.

The activities will often include:

• Mobile application security testing
• API security reviews
• Authentication & authorization reviews
• Source code review
• Cloud infrastructure security reviews
• Data protection & encryption testing
• 3rd party SDK & dependency analysis
• Compliance mapping against frameworks
• Vulnerability validation & risk prioritisation

The auditors look at the systems as interconnected parts and assess how the security controls are implemented across all parts of the system rather than looking at just one individual piece.

Why Businesses Conduct Security Audits?

The primary reasons a business will perform a mobile app security audit are to reduce its cyber risk exposure, comply with regulations, protect its users’ data, and build trust with customers.

Security audits are commonly performed when:

• A new mobile application is being launched
• A major new version of a product is being released
• The mobile application requires a security certificate or is subject to compliance audits
• Significant architectural changes to the mobile application or its infrastructure have been made
• A merger, acquisition, or investment transaction is underway
• A regular feature of a continuing security program.

The cost to fix vulnerabilities early is usually far less than dealing with a security breach post-deployment. It is very common to find security vulnerabilities during mobile app security audits that may go unnoticed during traditional development and testing.

Some common vulnerabilities that are discovered:

• Insecure API endpoints
• Broken Authentication
• Broken password reset mechanisms
• Insecure token storage
• Over-privileged user accounts
• Mis-configured cloud environments
• Weak encryption methods
• Disclosure of sensitive information
• Vulnerable third-party libraries
• Lack of security logging and monitoring

For instance, a marketplace app may uncover an exposed API endpoint that can be called by anyone with the right inputs to either bypass restrictions or gather data; broken password reset logic that allows easy account compromise; insecurely stored tokens that can be siphoned off by attackers; and user roles with overly broad permissions. Unmitigated, this would expose the organisation and its users.

Deliverables You Should Expect

A good mobile app security audit is about more than just finding technical issues; it’s about helping the business understand the risk, business impact, and actions required.

Some of the typical deliverables that would be expected:

• An executive summary targeted at business stakeholders
• A detailed vulnerability report
• The findings assigned a severity rating and the level of risk
• Proof-of-concept to demonstrate that the vulnerability can be exploited (if applicable)
• A gap analysis against relevant compliance requirements
• Recommended remediation actions
• Technical findings were identified and mapped to specific systems
• Retesting of corrected vulnerabilities (if within scope)

These deliverables empower development, security, and compliance teams with the knowledge and action plan required to mitigate identified risks and to provide evidence to regulators, business partners, and customers that appropriate measures have been taken.

What Is Reviewed During a Security Audit?

Area	Examples
Mobile Client	APK/IPA security, local storage security, reverse engineering risks
APIs	Authentication, authorisation, rate limiting, input validation
Backend	Access controls, server configuration, business logic security
Cloud Infrastructure	IAM policies, storage buckets, network security
Data Security	Encryption, key management, data leakage prevention
Compliance	UK GDPR, PCI DSS, NHS DSP Toolkit, ISO 27001 controls

How Much Does a Mobile App Security Audit Cost?

The price of a mobile app security audit in the UK will more than likely fall between £2,000 and £50,000 or more, and this depends on the size and complexity of the mobile app itself, the level of assessment, the testing approach used, regulations and compliance needs, and how much the system is tested manually.

Small, basic, and uncomplicated applications will likely just need to undergo a standard vulnerability assessment, but complex and sensitive enterprise platforms such as SaaS, fintech, or medical-based applications may need source code reviews, API security testing, cloud security reviews, threat modelling, and compliance checks to ensure high standards.

A significant misconception that is held about security audit costing is that the price depends solely on the size of the application. Factors such as the number of APIs within an application, the roles a user has, any third-party integration, cloud security requirements, and regulatory responsibilities may contribute to audit effort to a greater degree than the number of pages or features within an app.

Whether the business wants a one-off audit, periodic compliance audits, or an ongoing testing regime must also be factored in, with each posing differing costs.

Average UK Pricing

Audit Approach	Typical Cost	Best For
One-Time Audit	£2,000–£25,000	MVPs, Pre-Launch Reviews
Annual Security Audit	£5,000–£30,000/year	SMEs & Growing Businesses
Continuous Security Testing	£15,000–£100,000+/year	Fintech, Healthcare, Enterprise

Startup vs Enterprise costs

The cost of a security audit is influenced by the size of your organisation, the nature of the risks, and your attack surface.

Typically, a startup may be solely focused on discovering critical vulnerabilities prior to launch and would therefore opt for a smaller attack surface for a narrower audit. However, the size and complexity of an enterprise’s multiple applications, APIs, cloud services, third-party connections, and regulatory requirements lead to a greater attack surface and, consequently, larger security audits.

As an illustration, a startup going for MVP development may spend between £2k and £6k for an initial assessment compared to an enterprise using customer-facing mobile platform technology, which might require an investment of between £20k and £75k or more for a security audit.

One-Time vs Ongoing Security Audits

Organisations often undergo an initial one-off security audit prior to launch or after a large product update. While a one-off security assessment will provide a snapshot of vulnerabilities present, applications evolve, and security risks can arise as new features are developed. Therefore, many organisations invest in a scheduled security review as part of a security program. An organisation’s recurring security tests will help organisations identify emerging risks, monitor and remain compliant, and reduce the possibility of expensive security events occurring between the main releases of an application. While requiring a larger commitment over the longer term, the increased investment in recurring security testing should ideally result in reduced overall security risk exposure and more predictable security spending than attempting to rectify security breaches post-incident.

Security Audit Cost by Business Size

Organisation Size	Typical Cost
Startup	£2,000–£6,000
Small Business	£5,000–£12,000
Mid-Market	£10,000–£25,000
Enterprise	£20,000–£75,000+

Mobile App Security Audit Cost Breakdown

Mobile app security audits come at a varied price because it depends on the number of tests, analyses, and validations that are required throughout the app’s whole ecosystem. While most companies look at the final bill, learning about how the cost of an audit is allocated helps both businesses to better understand and compare quotes, and ensures that critical security areas are not ignored.

During a security audit, there are typically several phases to consider:

First, you prepare a cloud risk assessment checklist. Then, there is a thorough review of source code and API security, followed by cloud security testing, and the final part, remediation validation.

Discovery & Scoping

Each security audit will begin with a discovery and scoping exercise. The aim of this exercise will be to get to know the application architecture, technology, roles, integration points and business logic and ultimately establish the scope for testing.

For a business that operates with several environments or a complex business process or multiple 3rd party integrations, the level of planning will need to be in-depth, and this will result in a higher cost of audit.

Threat Modelling

Threat modelling will provide attackers with a view of potential ways that a business application can be attacked. The attacker will map out the attack surface and the flow of information through sensitive systems, and examine the methods of authentication and business-critical features to focus testing efforts.

This stage is more critical to fintech, healthcare and enterprise applications as an attack could potentially result in a severe financial, operational or compliance issue.

Source Code Review

The source code review process involves auditing the code itself for any security weaknesses not apparent externally. Auditors will look for vulnerabilities in authentication logic, session handling, access controls, crypto implementation, error handling and input validation.

The cost will be dictated by the codebase’s size and technologies used.

API Testing

The majority of mobile applications consume a backend system or service through APIs. API testing primarily aims to identify weaknesses in controls such as authentication, authorisation, Business Logic vulnerabilities, Rate Limiting and leakage of sensitive data. An application that contains numerous APIs or utilises a microservices architecture will have a much larger API testing scope.

Mobile Client Assessment

The mobile client assessment ensures that the mobile application itself is secure. It is the role of the auditor to look at how data is stored on the client side, how credentials are handled and managed, the state of the session, and transport layer security, as well as how the mobile client has been hardened to prevent reverse engineering.

Aims to ensure no sensitive data can be extracted, security bypassed, or accounts compromised.

Cloud Security Review

Most mobile applications utilise cloud services to host API, database, storage and authentication services. The security of these services will need to be reviewed during the cloud security review phase, where identity and access management, permissions associated with cloud storage, network configurations and monitoring will be assessed.

Poor configuration of cloud resources remains one of the most prevalent causes of data compromise events.

Reporting & Retesting

The findings of the assessment will be documented, prioritised, and remediation guidance will be provided in a clear, actionable report. Many providers also offer retesting services to ensure vulnerabilities have been resolved.

The quality of the reporting will allow development teams to quickly remediate issues, and assist companies in providing reassurance to customers, stakeholders and regulatory authorities.

Detailed Cost Breakdown

Activity	Typical Hours	Typical Cost
Discovery Workshop	4–12	£500–£2,000
Threat Modelling	8–20	£1,000–£3,000
Source Code Review	20–80	£2,000–£10,000
API Testing	15–50	£1,500–£8,000
Mobile App Testing	20–60	£2,000–£8,000
Cloud Assessment	10–40	£1,500–£7,500
Reporting & Retesting	8–20	£500–£3,000

An example could be a medical mobile application handling patient information, where this would need a full threat modelling, source code review, API testing, cloud security assessment and a review of NHS compliance, and the overall audit may cost far more than a basic assessment of a simple, consumer-facing application with few features and low-risk data.

Compare your app’s security risk profile before you invest in an audit.

Mobile App Security Audit Cost Calculator

Mobile app security audits do not have set costs. Security firms typically determine prices based on the complexity of the app (number of screens), the architecture of the app, the integrations it uses and requires, the need to comply with regulatory requirements, and the attack surface.

Although each project is unique, by reviewing the elements that make an audit more extensive, businesses should be able to have a reasonable idea of a budget range to expect before hiring security specialists.

Cost Based on Screens

Another quick metric of complexity is the number of screens in an application. More screens typically indicate more workflows, user inputs, processing actions and business rules which must be audited by the auditor.

It is also not the screen count that dictates the pricing. A less complex 100-screen application may involve less work to audit than a highly complex 20-screen application that is highly integrated with the backend functionality.

Number of Screens	Typical Audit Cost
10–20 Screens	£2,000–£5,000
20–50 Screens	£5,000–£10,000
50–100 Screens	£10,000–£20,000
100+ Screens	£20,000+

Cost Based on APIs

One of the biggest attack surfaces associated with the current mobile application is that all of the APIs that are implemented will need to be tested for authentication, authorisation, input validation, business logic flaws, and data leakage. An application which relies heavily on its APIs will probably need more validation and testing.

Number of APIs	Typical Cost Impact
1–5 APIs	Base Cost
5–15 APIs	+20–40%
15+ APIs	+50–100%

Cost Based on Integrations

Many mobile applications rely on third-party services for payments, messaging, analytics, identity verification, customer support, marketing automation, and cloud functionality. Each integration introduces additional security considerations and increases the scope of an audit.

Examples include:

• Payment gateways
• Social login providers
• CRM platforms
• Analytics tools
• Identity verification services
• Cloud storage providers
• AI and machine learning services

The more integrations an application depends on, the greater the amount of testing required.

Cost Based on User Roles

Applications supporting multiple user types typically require more comprehensive security testing. Auditors must validate access controls, permissions, privilege escalation protections, and role-based security across all user journeys.

For example, a marketplace application may contain separate permissions for customers, vendors, support teams, finance staff, and administrators. Each role creates additional testing requirements and increases audit effort.

User Roles	Typical Cost Impact
1–2 Roles	Base Cost
3–5 Roles	+10–25%
5+ Roles	+25–50%

Example Security Audit Estimate

For example, the healthcare application with:

• 75 application screens
• 18 APIs
• Several 3rd party integrations
• 5 user roles
• NHS compliance requirements

The audit of this kind of application usually includes: Source code review, API security test, mobile application testing, cloud application security, threat modelling, and compliance mapping.

Normally, organisations could expect a security audit budget of 15K-30K+, depending on how many tests the client wants and the company’s methodology.

Although online calculators give a good estimation of the cost of a security audit, the final quote is normally provided after the audit organisation understands the application architecture, how it is integrated, what compliance it needs to follow and so on.

What Factors Affect Mobile App Security Audit Costs?

The cost of security audits on mobile apps differs since every app is unique; some can be audited in a few days, and others, depending on the complexity and size, may take a couple of weeks to be tested.

Other factors that influence the overall cost include the complexity and size of the app, number of integrations, features of the app, level of testing required and also compliance requirements. Other related services like manual vulnerability assessment, architectural review, and mitigation may also influence the overall cost.

App Complexity

The complexity of a mobile app security audit will have a large impact on the overall cost. As a mobile application becomes more complex with additional functionality, workflows, integrations and user interactions, the potential number of attack surfaces also expands. This will require security testers to spend additional time examining features, business logic and possible exploit pathways.

An appointment booking app, for example, will likely not require as much security testing as an application that is, for instance, a multi-vendor e-commerce marketplace, banking application, or healthcare app, where a range of sensitive information may be involved.

User Base Size

Large-scale systems which serve thousands, or even millions, of users are generally subjected to a more thorough level of security review as the potential for a breach is increased dramatically. Review time may be extended for the controls over authentication, authorisation, recovery of accounts, prevention of abuse and security considerations for scaling.

API Ecosystem

Nowadays, we often see mobile applications having multiple APIs for various purposes: payment, authentication, messaging, analytics, business customer data, business process, and many more.

More and more APIs mean more attack surfaces need to be tested: broken authentication, information exposure, IDOR, insufficient rate limiting, and business logic flaws.

It can be seen that as the API count goes up, so does the cost and the audit effort.

Third-Party SDKs

Some of these (analytics, ads, payment, social login, engagement) may rely on SDKs (Software Development Kits) to perform specific functions. Such integrations can greatly speed up development, but can also bring security and privacy risks. An auditor may check SDK permissions, how the SDK collects data, its version and any known security vulnerabilities.

Cloud Infrastructure

Modern applications widely use the cloud to host their APIs, databases, file storage, authentication systems, and their backend.

Cloud security assessments might require auditing storage access rights, network topology, access control lists, identity management and access policies, monitoring mechanisms, and infrastructure hardening.

Complex cloud architectures built for modern applications typically require more testing effort than those with simpler, non-cloud-based architectures.

Data Sensitivity

The nature of the data being processed dramatically affects audit scope and the risks involved. Applications that involve payment, medical, biometric or financial data or PII generally necessitate greater testing than applications that deal with public data with a low-risk profile. High-risk data typically leads to enhanced security, rigorous testing and additional regulatory requirements.

Compliance Requirements

Regulatory and industry standards can have a large impact on the scope of the audit work required. Companies within a regulated industry need auditors to test security controls against specific frameworks and compliance obligations.

These include:

• UK GDPR
• PCI DSS
• NHS Data Security and Protection Toolkit
• FCA rules
• ISO 27001
• Cyber Essentials

These types of audits typically require additional documentation review, control testing procedures, evidence gathering and reporting, which drive up the audit costs.

Cost Drivers and Their Impact

Factor	Low Impact	Medium Impact	High Impact
APIs	1–5	6–15	15+
Screens	Under 20	20–75	75+
User Roles	1–2	3–5	5+
Cloud Services	Basic	Moderate	Extensive
Compliance Requirements	None	GDPR	NHS, FCA, PCI DSS

These cost drivers provide a basis on which to predict the range of audit budget required. They also enable customers to better compare the pricing presented in vendor proposals. Often these additional items, such as compliance requirements, API complexity and sensitivity of data, will have more effect on the pricing than the size of the application.

How Security Auditors Determine Project Scope

Prior to submitting a quote, security auditors work with a client to understand the applications’ architecture, functionality, risk posture, and regulatory requirements to define the scope of the audit. This scope provides the auditor with a reasonable estimate for the amount of work required and helps them to target testing on the aspects with the highest security risk. Larger attack surfaces, regulated data, integrated components, or compliance requirements generally call for more comprehensive audits with higher audit costs.

Attack Surface Analysis

When planning your security audit, one of the first things to assess is the attack surface of the application.

Auditors consider the potential targets of attackers, such as:

• Mobile applications
• APIs
• Backend systems
• Cloud environment
• Databases
• Integrations with third-party components
• Administration interfaces

A larger attack surface indicates more scope is likely needed. For instance, an application with hundreds of APIs and many third-party components will typically require more investigation than a simple mobile application that is standalone.

Threat Modelling

Threat modelling assists the auditors in understanding ways that an attacker might leverage weaknesses in the application.

During threat modelling, security experts typically analyse:

• The critical assets and confidential information
• The probable threat actors involved
• The possible attack vectors utilised
• The most critical business processes involved
• Existing security controls implemented

Based on these results, it can be concluded which components should be tested in detail, where security experts’ time and attention should be directed.

Architecture Reviews

The scope of an audit may also be impacted by the application architecture. The auditor will look at the interaction of all components of the application, for example:

• Mobile clients
• APIs
• Backend services
• Databases
• External interfaces
• Identity and Access Management services

When a complex architecture is in place, more testing may need to be done to ensure the security controls are working across all environments.

Infrastructure Reviews

Mobile app security audits may not be confined to the mobile app. The auditor may review:

• Cloud services
• Network configuration
• Storage
• Identity and access controls
• Monitoring and logging capabilities
• Backup and recovery policies

If the application is spread across different clouds, services or regions, more than likely there is a greater emphasis on the infrastructure.

Compliance Mapping

Audit scope can also increase significantly as a result of regulatory and industry requirements.

Regulated entities will be asked to have controls tested against the following types of frameworks:

• UK GDPR
• PCI DSS
• ISO 27001
• NHS Data Security and Protection Toolkit
• FCA regulations

Mappings require a number of extra tasks such as additional documentation review, evidence gathering, control verification and reporting; the increased volume of these will add both to the audit effort and cost.

Scope Expansion Factors

The following characteristics commonly increase the amount of testing required during a mobile app security audit.

Factor	Impact on Audit Effort
Multi-Tenant Architecture	+20–30%
Microservices Architecture	+25–40%
Third-Party APIs	+10–25%
AI Integrations	+20–35%
Payment Processing Functionality	+20–40%

Finally, the cost of a security audit is also dictated by the level of risk and complexity involved, and the thoroughness of testing, rather than just size. Though two mobile apps might seem similar on the surface, they can demand a widely varying investment in security assessment time, due to their respective architecture, dependencies, compliance requirements, and threat landscape.

Mobile Application Security Audit Cost By Application Type

The cost of auditing a mobile application can vary depending on the type of app being tested. Consumer applications that deal with less sensitive data, have simple workflows, or are not in regulated industries will tend to cost less than applications that deal with extremely sensitive data, are extremely complicated, and/or exist within regulated industries.

ECommerce Apps

eCommerce mobile apps will typically need payment workflows, user accounts, and API calls; data security will be heavily scrutinised. Integrations like those from payment gateways and/or inventory systems will have the ability to expand the cost of the audit.

Marketplace Apps

Marketplace applications can be more difficult to audit due to multiple roles and/or permissions. The auditor will also spend more time verifying business logic.

Healthcare Apps

Due to the highly sensitive nature of patient data and regulatory requirements (HIPAA), healthcare applications will typically be among the most expensive mobile applications to audit.

Fintech Apps

Due to the potential financial impact and complexity that financial technology mobile applications carry, they will always need significant security testing.

SaaS platforms

Applications running within a SaaS model tend to have a larger number of potential issues, as is common for applications with large user bases, cloud environments, and a lot of external integrations, which add cost and time.

AI Mobile Applications

AI mobile applications have all the traditional security risks that any mobile application would have, on top of a set of new security risks tied directly to AI models. These are as follows: AI model security risks, Data Privacy, Prompt Injection, third-party AI service security, and API exposure to the AI model, all of which contribute to additional cost.

Cost by App Type

App Type	Typical Audit Cost
Fitness App	£3,000–£8,000
eCommerce App	£4,000–£12,000
Marketplace App	£6,000–£18,000
SaaS App	£5,000–£20,000
Healthcare App	£8,000–£25,000
Fintech App	£10,000–£35,000+
AI Mobile App	£15,000–£50,000+

Mobile App Security Audit Cost by Development Stage

The level of development can have a great impact on the amount spent on audit and the amount spent on fixes. Security audits in the early stages of development require fewer resources, and the fixes may not be fully ingrained in a production system. The more the system ages, the more features, interfaces, and role types there are, and the more components that make up the overall system, and therefore the broader scope.

Cost by Product Maturity

Stage	Typical Cost
MVP	£2,000–£5,000
Pre-Launch	£5,000–£12,000
Growth Stage	£8,000–£20,000
Enterprise Scale	£20,000–£75,000+

An audit performed during the MVP or prior to launch allows critical vulnerabilities to be found and rectified prior to the product reaching real customers or impacting the business. While an issue identified once live is technically found later, it is also likely to require more extensive effort and operational overhead in order to rectify it.

Example: A critical authentication vulnerability detected during the MVP phase might only cost approximately £2,000 to correct, compared to an authentication vulnerability identified post launch, costing more than £20,000, taking into consideration the development effort, re-testing, operational disruption, and customers.

Mobile App Security Audit Cost by Data Sensitivity 

One of the most crucial elements impacting audit cost is the nature of the data that an application processes. Applications which handle very sensitive data will require more extensive testing, more robust security controls and typically additional compliance validation. The greater the risk associated with a data breach, the greater the level of assurance that needs to be derived from the security assessment.

Data Type	Risk Level	Typical Cost
Public Data	Low	£2,000–£5,000
Customer Profiles	Medium	£5,000–£12,000
Payment Data	High	£8,000–£25,000
Medical Records	Very High	£10,000–£30,000
Biometric Data	Critical	£15,000–£40,000+

Applications that process payment data may need more security testing in relation to transactions, encryption, authentication controls and PCI DSS. Healthcare applications processing sensitive patient data may also need more security testing to ensure sensitive medical data is processed correctly and all relevant compliance laws are followed.

Apps processing biometric data (like facial recognition data, fingerprinting data or identity checking records) tend to have the highest audit cost due to the risks concerning data security, privacy and compliance associated with handling that data.

Complexity of the application is a cost factor, but often data sensitivity will more accurately predict the size and scope of a security audit.

Mobile App Security Audit Cost by Platform Type

Platform	Typical Cost	Security Focus Areas
Android	£3,000–£12,000	APK analysis, root detection, local storage security
iOS	£3,000–£12,000	Keychain security, jailbreak protections
Flutter	£5,000–£15,000	Shared code security, package dependencies
React Native	£5,000–£15,000	Native bridge testing, dependency risks
Native Android + iOS	£8,000–£25,000	Dual-platform assessment

Mobile App Security Audit Cost by Testing Depth

Not all security audits are equal in assurance. Some assessments involve significant automated scanning while others require extensive manual testing, source code analysis, threat modelling, and exploits from professional security researchers.

The depth of testing is directly proportional to the time, skill and effort required for an audit.

Automated Scan

Automated scans use security tools to find known vulnerabilities, configuration errors, obsolete dependencies, and known weak points in mobile apps. Automated scans lack the ability to find business logic errors or sophisticated vulnerabilities and can produce a lot of noise (false positives).

Standard Audit

Standard security audits use a combination of automated scanning, manual validation, and some specific security testing. Standard audits provide wider coverage of vulnerabilities and are often used by start-ups and SMEs due to their relatively low cost compared to other security assessment methods.

OWASP MASVS Audit

An OWASP MASVS-based assessment looks for mobile application vulnerabilities in relation to recognised mobile application security standards. MASVS assessments often involve much more intensive tests of authentication, data storage, crypto, communication security, and resilience controls.

Advanced Manual Assessment

Advanced assessment procedures involve significantly more comprehensive manual security testing by an expert security consultant. Vulnerabilities that automated scanning tools would never detect can often be found during advanced assessments. Common vulnerabilities missed include business logic weaknesses, privilege escalation flaws, and complex authentication failures.

Red Team Exercise

A Red Team exercise simulates an attack against an organisation’s mobile application environment. These types of engagements can be extremely bespoke but are always centred around probing for the application (and its surrounding systems) to be successfully attacked using real-world tactics and techniques across numerous vectors, including: application interfaces, supporting APIs, and associated cloud services.

Security Testing Levels

Assessment Type	Typical Cost
Automated Scan	£500–£2,000
Standard Audit	£2,000–£8,000
OWASP MASVS Audit	£5,000–£15,000
Advanced Manual Assessment	£10,000–£30,000
Red Team Exercise	£20,000–£75,000+

Compliance Requirements That Increase Audit Costs 

It’s possible that your application will need to be compliant with a standard. This can have a substantial impact on the overall cost of a mobile application security audit. Besides the testing to identify weaknesses in your application, an auditor also needs to carry out other tasks such as testing security controls, analysing documents, collecting evidence and linking findings with regulatory and industry standards.

The more demanding the standards you must be compliant with, the higher level of testing you will be expected to undertake, along with a wider scope of testing.

• GDPR: If your company collects or processes data belonging to a person, then it is important to evidence that you have sufficient security measures to ensure that it is secure. Audits assess access controls, data encryption, storage of data, and data protection controls in support of these compliance requirements.
• PCI DSS: Applications that store, process or transmit payment card data may also have specific testing that the payment workflow, authentication controls, data encryption, cardholder data protection measures, etc., need to be tested in order to support the security compliance requirements. These require a considerable amount of effort.
• FCA: If your application is FinTech and is regulated in a specific country, you will likely be required to have much more rigorous testing of the mobile application in support of data protection, risk management and operational resilience requirements.
• NHS DSP Toolkit: If your application manages patient information, then you must meet NHS security standards, which typically require you to present evidence regarding access management, audit logging, encryption, incident response, and data protection controls.
• ISO 27001: Applications maintained by organisations attempting to gain or maintain ISO 27001 certification will need technical controls to be assessed as part of this, and will likely require much more review of documentation and the provision of evidence, which will increase overall costs.

Compliance Cost Multipliers

Compliance Standard	Typical Cost Increase
Cyber Essentials	+5–15%
GDPR	+10–20%
ISO 27001	+10–25%
PCI DSS	+15–30%
FCA Requirements	+20–40%
NHS DSP Toolkit	+25–50%

Security Audit vs Penetration Testing Cost

Security Audit

Security audits are a high-level approach to risk analysis, as they incorporate review of all aspects of technical controls, application design, cloud configuration, development processes, and compliance requirements. Identifying gaps and prioritising fixes.

These assessments can be useful for: compliance projects, risk management programs, investor due diligence, and security pre-launch review.

Penetration Testing

Penetration tests are all about finding and exploiting vulnerabilities within a specific set of parameters. Testers aim to bypass security controls, increase privileges, achieve unauthorised access, and determine potential attack routes.

These tests can be extremely useful for determining actual attack paths and the implications that vulnerabilities may cause.

Side-by-Side Comparison

Factor	Security Audit	Penetration Test
Cost	£5,000–£20,000	£4,000–£15,000
Source Code Review	Yes	No
Compliance Mapping	Yes	Rarely
Exploitation Testing	Limited	Extensive
Architecture Review	Yes	Limited
Cloud Configuration Review	Often Included	Sometimes
Remediation Guidance	Comprehensive	Vulnerability Focused

Hidden Costs Businesses Often Miss

Hidden Cost	Typical Cost
Vulnerability Fixes	£2,000–£20,000+
Developer Rework	£1,500–£15,000
Infrastructure Changes	£1,000–£25,000
Retesting	£1,000–£5,000
Compliance Remediation	£3,000–£30,000

Fixing vulnerabilities

Finding a security hole isn’t the end of the job; developers must address the security flaw, check in their changes and retest to ensure the flaw has been properly fixed. Generally, fixing a problem is more expensive than finding it.

Developer rework

A late finding of a security vulnerability often requires code changes, architectural alterations to an application, or improvements to quality assurance processes. The cost of fixing a flaw increases the more deeply the security flaw is embedded in the application.

Infrastructure changes

Some security reviews may uncover security flaws within a cloud environment, storage, access controls or network configuration. Fixing a security vulnerability in any of these could require infrastructure redesign, migration or new security tools.

Retesting

Many companies test for vulnerabilities again after they have been remediated. Retesting confirms that an issue found by the security audit has been fixed successfully, and also confirms that the changes implemented during remediation didn’t create new security issues.

Compliance changes

Some applications are run within a particular compliance framework, and any GAPs uncovered during a security review may require updating security policies or additional controls, improved documentation or technical processes to comply with regulations.

Businesses ought to consider security reviews as part of their overall security programme. By estimating the cost of remediation and follow-up work, the entire security program budget can be more accurate.

How Much Does It Cost to Fix Security Vulnerabilities?

The costs for remedying security vulnerabilities range in magnitude based on the severity of the vulnerability, the systems involved, and when the vulnerability is identified. Certain fixes can be addressed through relatively minor code modification; however, other fixes involve substantial code rewrite, changes in infrastructure, additional testing, and so forth. Frequently, the costs of remediation are more substantial than the cost of identification during the security audit.

Remediation Cost by Severity

Severity Level	Typical Fix Cost
Low	£500–£2,000
Medium	£2,000–£5,000
High	£5,000–£15,000
Critical	£15,000–£50,000+

Low Severity

Low-severity findings are minor security defects that are unlikely to result in any sort of compromise to the security of the application. Often, issues such as missing security headers or information disclosure points, or sensitive misconfigurations, pose minimal security risk and are typically easy to fix with a small amount of effort from the developer.

Medium Severity

Medium severity findings are those that have the potential to add to the success of a security incident. Examples can be anything from lacking proper input validation to having weaker session management controls and having the wrong configuration around logging/monitoring controls. Generally, medium-severity findings are relatively easy to solve using changes to application code and can often be fixed by simply reviewing the application code and testing for success.

High Severity

High-severity findings are issues with more significant potential, such as those that can lead to exposure of sensitive data, unauthorised compromise of user accounts, or bypassing important controls. Such things as broken access controls, insecure authentication and API access controls could all fall under this category. Issues of this nature typically involve several parts of the application and may require a significant amount of developer resources to fix.

Critical Issues

Critical vulnerabilities have the greatest potential to result in large-scale data compromise, a full system compromise, or unauthorised access to data. Remote Code Execution (RCE), unauthenticated administration portals and certain credential bypassing exploits are usually considered critical, as is a broad misconfiguration of cloud-based services. These findings must be resolved immediately and will most likely involve significant retesting before being put into production.

Cost of deferring the fix

Security flaws tend to get more expensive to remediate the longer they are allowed to remain unfixed. A vulnerability found during the mobile app development lifecycle will probably cost considerably less to fix than one found after it has gone to production, requiring emergency fixes and communication with the user. Due to this, many organisations are implementing security reviews earlier in the development lifecycle.

Example Remediation Budget

Activity	Typical Cost
Security Audit	£12,000
Vulnerability Remediation	£8,000
Retesting	£2,500
Compliance Validation	£3,500
Total Security Investment	£26,000

How to Reduce Mobile App Security Audit Costs Without Compromising Security

It’s crucial to view a security audit as an investment toward risk mitigation, not merely an expense in the name of compliance. However, that doesn’t suggest organisations ought to spend more money than necessary; by proper preparation and through a well-defined scope, businesses can significantly reduce audit expenditures, whilst receiving relevant security assurance.

Conduct Security Reviews Early in Development

Security problems discovered during the development stage are generally quicker and cheaper to resolve than after the system has been launched. Therefore, performing audits earlier in the software development lifecycle can reduce both testing and remediation costs.

Define the Scope of your audit clearly.

Lack of a clear scope often results in scope expansion, increased testing efforts, and, in the long run, additional project cost. Businesses must provide specific applications, APIs, infrastructure components, and environments to be tested prior to engaging a security provider.

Keep documentation at hand.

The ability to easily present architecture diagrams, API documentation, definitions of users’ roles, information regarding the infrastructure based on cloud services, and data flow diagrams will significantly ease discovery, scope preparation, and, consequently, reduce the cost related to such efforts. Well-documented systems tend to be quicker to audit.

Prioritise areas most prone to attacks

Not all components within an application are of the same level of security risk; focusing on tests related to authentication systems, payment features, APIs, administration areas, and sensitive data processing is more useful and will assist in keeping the cost down.

Address prior findings before a new audit.

Previous findings, outdated software libraries, and obvious misconfigurations should be remediated before beginning an audit to allow auditors to focus on finding new issues rather than retesting items already found and fixed.

Select the appropriate level of security testing.

The breadth of tests performed should be adequate for your business’s risk profile, compliance requirements, and sensitive data holdings. The scope of a security assessment will vary according to those needs; a startup’s MVP cannot receive the same treatment as a regulated fintech enterprise system.

Bundle your services

Businesses may achieve savings on costs through providers that offer bundled services that include security audit, pen-test, compliance assessment, and retesting. This consolidation can simplify administration and ensure the continuous progress of your security posture.

How to Choose a Mobile App Security Audit Provider in the UK

Beyond determining whether an audit is required, it is essential to choose the right security audit provider. While the cost of an audit should be a consideration, organisations should not ignore factors such as technical competency, testing approach, report quality, and the provider’s knowledge of the specific industry.

The lowest price often represents the poorest value for money. A deep audit conducted by experienced security experts is able to identify weaknesses and vulnerabilities that automated scanners and cheap reviews may not detect.

Industry Experience

Seek out companies that have performed audits on applications comparable to your own. An organisation that frequently reviews fintech, healthcare, SaaS, or e-commerce applications is better placed to identify security concerns relevant to the specific sector and to address any relevant compliance issues.

Testing Methodology

Ask your potential security auditor how the review will be conducted. Trusted providers will typically utilise a combination of automated scanning, manual testing, and reviews of application architecture, APIs, and risk validation procedures rather than simply utilising security tools.

Compliance Expertise

If your organisation needs to meet specific regulatory and compliance requirements such as UK GDPR, PCI DSS, ISO 27001, FCA standards, or the NHS DSP Toolkit, then you must seek a provider that understands these regulations.

Such an approach reduces the need for additional fixes and compliance checks at the end of the review.

Report Quality

A security audit is only useful if the findings are clearly communicated and understood. If possible, review sample reports and look for companies that include:

• An executive summary
• The classification of risks
• Technical findings
• Recommendations for fixing issues
• A summary of compliance requirements
• A promise of retesting when issues have been fixed

Certifications and Credentials

Further confidence can be placed in a provider that has achieved various security certifications. Commonly accepted professional certifications in the security industry include:

• CREST
• CHECK
• OSCP
• CISSP
• CEH
• An ISO 27001-related qualification

While this should not be a key deciding factor, certifications generally assure a minimum standard of technical ability.

Questions to Ask Before Hiring a Security Audit Provider

Before choosing your security audit provider, ask a few crucial questions.

Does your audit involve manual testing?

Many cheap audits will heavily rely on automated scanners. While these can find the more common vulnerabilities, they are unlikely to find bugs in business logic, access control, or complex attack paths.

By assessing how much manual testing you perform, you will know the depth of the audit. A provider who is doing comprehensive manual testing is likely to uncover the high-risk vulnerabilities.

Do you test for APIs?

Today, many mobile applications depend heavily on APIs to authenticate, send data, perform payments, or other operations. APIs are also one of the most popular attack surfaces.

Asking this question ensures that you have the systems that handle your business-critical functions or sensitive data covered.

Do you test source code?

Some security tests examine the application from an outside perspective, whereas other tests include a full source code review.

Source code analysis allows for the uncovering of bugs that could not be found in external testing. You may find insecure code or logic.

What security standards or methodologies do you follow?

There can be a huge variation in the quality of a security audit, and one aspect that is strongly influenced by the standards used is how testing is performed.

Aligning with respected standards, like OWASP MASVS, OWASP Mobile Top 10, NIST, or a particular industry standard, may mean you get a much better quality of test.

Do you have experience testing apps in our industry?

The risks are hugely different in many industries. A fintech application may present different threats than a health application or an eCommerce marketplace.

Asking your provider will help you ensure that they have relevant experience in assessing the threats or regulatory environment in which you operate.

What do we get at the end of the test?

The true value of a security audit should not only be the identification of the vulnerabilities found, but also the reporting provided at the end.

A typical delivery can be a top-level executive summary to a more in-depth report outlining all the vulnerabilities found, their risk level, and recommendations to fix them.

Is re-testing included?

The identification of vulnerabilities is one aspect of the process; however, once the relevant findings have been fixed by development, it’s important to ensure that they have been fixed correctly.

This will assure you that the discovered flaws no longer exist.

Does your audit facilitate compliance?

Businesses that need to comply with specific regulations or standards, such as UK GDPR, PCI DSS, NHS DSP Toolkit, FCA regulations, or ISO 27001, may not get a good enough test from a generic security audit.

If you do have regulatory or compliance requirements, then it is worthwhile ensuring that your provider is knowledgeable of your needs and can align testing results to relevant compliance rules.

Conclusion

The cost of a mobile app security audit in the UK is highly variable and depends on your app’s complexity, the type of data it stores, and the regulatory and compliance factors, along with the test approach employed. Though it can cost as little as a few thousand pounds for a basic assessment, the larger apps handling sensitive data and extensive infrastructure may require a more significant investment.

Even considering the price of an audit, it’s never quite appropriate not to take one due to cost, but rather, to always be balancing it against the potential risks and fallout. Often, fixing and identifying the hole will be far more inexpensive than dealing with a data breach investigation, an investigation by a governing body, or the backlash from losing your clients’ trust.

From new applications to improving systems to complying with regulations, a security audit will make clear where an app stands with security. By being informed of the cost drivers and choosing the best audit scope, businesses are able to confidently invest money wisely to obtain the most secure mobile apps possible.

FAQs

How much is a mobile app security audit in the UK?

A mobile app security audit in the UK costs £2,000-£75,000+. This is determined by the complexity of the app, the extent of testing required, regulatory needs, the number of APIs, integrations, and cloud service use.

What determines the cost of a mobile app security audit?

Application complexity, APIs, third-party integrations, cloud environment, sensitive data held, regulatory requirements, test intensity, and manual source code review will affect mobile app security audit pricing.

Why is a fintech security audit more expensive?

A fintech security audit costs more as the transactions conducted within, regulations expected, prevention of fraudulent activities, and risk related to the data held dictate and require a more in-depth and detailed test.

Are Flutter apps cheaper to audit than native?

At times, yes. This is as a result of codebases and the potential sharing of code; however, the app complexity, its associated APIs, integrations, and system configuration will ultimately determine costs.

How much does a penetration test cost?

In the UK, a mobile application penetration test costs £4,000-15,000. This depends on the test parameters, complexity, and whether mobile, API, or infrastructure tests are included.

What does a mobile app security audit cover?

Mobile application, API, source code, cloud security testing, architecture assessment, and compliance mapping.

How long does a security audit take?

In general, most mobile app security audits take anything from 1-4 weeks to complete; however, it does depend on the application size and complexity, the number of integrations used plus the amount of manual testing conducted.

Do security audits cover API testing?

Yes, the majority of security audits include testing with a check performed of the applications’ authentication, authorisation, and inputs, along with rate limiting, data input, and risks to data leakage.

Do security audits cover source code reviews?

It depends on the audit performed; however, for most, an assessment will involve an application black box review and then a white box review, where the source code is examined, for higher rates of issue detection.

How often should mobile applications be security audited?

It’s a general recommendation for mobile applications to undergo an annual security audit or after any new system updates or architecture changes. Additionally, you’ll need an audit if new types of sensitive data are handled by the app.

Does GDPR enforce a security audit?

GDPR do not specify a security audit but instead requires organisations to have “appropriate technical and organisational measures” in place, and a security audit enables organisations to identify whether they hold such measures.

How does PCI DSS influence audit costs?

PCI DSS’s stricter measures regarding the secure handling of cardholder data have led to more thorough testing of cardholder systems, increasing the cost of security audits.

What security audits are required for NHS apps?

NHS apps are required to comply with the NHS Data Security and Protection Toolkit (DSPT). This is where the access controls, logging, and encryption of mobile apps are reviewed, amongst other elements.

Does a mobile app security audit cover ISO 27001?

No, ISO 27001 tests information security measures rather than acting as a testing methodology. However, a security audit may feature control testing, allowing a business to achieve ISO 27001 certification.

Is a mobile app security audit worth the money?

Yes, a mobile app security audit allows a business to pinpoint security flaws and therefore avoid the expense of data breaches.

What are the financial implications of NOT conducting a security audit?

Not having a security audit performed on mobile applications will have implications of data breaches, fines, and a damaged brand name and reputation.

How much does it cost to fix vulnerabilities found during an audit?

Remediation can range significantly depending on the severity of a vulnerability and the affected system. It can cost anywhere between £500 and £50,000+ per vulnerability.

How do I choose a company for a mobile app security audit?

Choose based on expertise, their test methods, supported compliance, detailed reports provided, and whether manual code review is part of their service.

What are the red flags regarding a security audit company quote?

Be sceptical if the company’s quote is too cheap or if it’s vague on their test methodology, compliance support, or if they don’t include manual source code reviews.

Should I just hire the cheapest security audit company?

The cheapest available security audit company is often not the best. Low cost means poor, non-detailed testing with potential overlooked threats and risks, costing the company much more in the long run.