Code audits can range from a security-focused source review to a wider assessment of architecture, technical debt, dependencies, performance, and maintainability. The companies below cover different parts of that spectrum, with options for mobile applications, enterprise systems, SaaS products, and legacy software.
Gilzor focuses on code audits for mobile applications, examining technical risks that can affect product health and future development. Its audit scope includes architecture, technical debt, security flags, performance bottlenecks, dependency issues, build pipeline risks, crash patterns, and compatibility concerns. The company presents its findings as an independent assessment, with recommendations prioritized around the issues that need attention. This approach can be useful when a mobile product has recurring defects, stalled releases, declining ratings, or other signs that the underlying codebase needs a closer technical review.
Itexus approaches code auditing through its Project Audit and Rescue service. The company assesses existing software for code quality, security, stability, and performance, with the broader goal of getting troubled projects back on track. The service also covers documentation recovery, refactoring of problematic code, technology upgrades, and improvement of development processes. Itexus has a strong fintech focus, with more than 300 fintech projects across 23 countries. That makes its audit offering particularly relevant to financial products where existing code has to be evaluated alongside security, integrations, and regulated workflows.
OSKI Solutions includes technical auditing in its approach to legacy modernization and software support. Its services cover audits of codebases, dependencies, data, integrations, and existing workflows before modernization begins. The findings help identify brittle areas, add tests and safeguards, and plan incremental refactoring rather than replacing an entire system at once. OSKI works mainly with established business systems and technologies including .NET, Node.js, React, Angular, Umbraco, SQL Server, PostgreSQL, AWS, and Azure. Its audit work fits teams that need to understand and stabilize an existing system before making significant changes.
Securitum takes a security-first approach to code auditing. Its Source Code Review service examines an application's codebase for security flaws, vulnerable libraries, and design weaknesses, combining automated tooling with expert manual analysis. The company also connects source review with blackbox testing, allowing findings from external testing to guide the inspection of specific security hotspots. This makes Securitum more focused on application security than on a general software quality review. Securitum is based in Kraków and provides source code review as part of its broader application security and penetration testing services.
Lengreo combines web development, mobile development, and technical services with code-related review work. Its code audit services cover source code for structural weaknesses, security concerns, performance bottlenecks, and overall quality. The company operates from Amsterdam and Kyiv and provides custom web and mobile development. For organizations that want an audit connected to follow-up development work, this broader engineering setup can be relevant. Its technology and marketing services also cover areas such as SaaS, cybersecurity, software development, fintech, healthcare, and Web3.
X41 D-Sec is more narrowly focused on application security and source code auditing than a typical software development agency. Its security code audit starts with a design workshop and codebase walkthrough, followed by threat modeling and a combination of automated and manual source review. Reviewers discuss findings directly with developers, and the company can conduct audits remotely or on-site. For particularly sensitive engagements, X41 can work on the client's own hardware so the source code remains under the client's control. Findings are reported using CVSS and CWE scoring where applicable.
Net-devs provides an AI-accelerated audit of enterprise codebases as part of its transformation services. Its audit covers architecture, dependencies, risk hotspots, security posture, testing coverage, cost of ownership, and limits to development velocity. The findings are then turned into a sequenced modernization roadmap with effort estimates and dependencies. Its enterprise development work spans .NET, Java and Kotlin, Node.js, Python, Go, and cloud platforms including Azure, AWS, and GCP. This puts net-devs closer to the technical audit and modernization side of the market than to a security-only source code review.
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Mobian Studio is primarily a software development partner, but it also provides technical reviews and targeted fixes for existing codebases. The company's current positioning centers on mobile and AI solutions, with work spanning backend systems, APIs, cloud infrastructure, and QA. Mobian also emphasizes clean architecture, documented code, and code quality as part of its engineering process. Its European base is in Tallinn, Estonia. For companies looking for an engineering team that can inspect an existing product and then continue with development or stabilization work, Mobian is a relevant option, although its audit offering is less narrowly defined than dedicated security audit firms.
DICEUS offers dedicated software code audit services covering the source code, technology stack, architecture, performance, documentation, and security. Its audit process includes checking frameworks and libraries, manually analyzing the codebase, assessing performance, and documenting identified issues in a final report. The company also works with clients on assessing existing applications, reviewing frontend and backend code, examining outdated technologies, and evaluating software against established audit practices. DICEUS maintains a global delivery structure with a center in Poland, Denmark and several European offices.
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SoftPro is a Warsaw-based software development company working on custom software, web applications, cloud solutions, and AI-related projects. Its broader engineering services include code review practices alongside custom development and long-term software support. The company uses technologies such as Azure, ASP.NET, .NET Core, React, and Node.js across its development work. It can therefore be considered for code quality and engineering review needs connected to a wider software development engagement rather than a standalone specialist security audit.
Krononsoft offers a dedicated third-party code audit service covering software quality, structure, architecture, maintainability, coding style, duplication, code smells, and vulnerabilities. The company provides both standard and custom audit packages, with the latter adding a deeper assessment and improvement roadmap. It also offers a separate approach for AI-generated and AI-assisted software, focusing on weak abstractions, hidden technical debt, insecure defaults, and maintainability problems. Its code audit services also cover technical reviews of frontend, backend, database design, and architecture.
A-listware includes code review and audit-related work within its software development, testing, and cybersecurity services. The company works across software development, application management, application security, application testing, infrastructure, and modernization. Its secure code review services can be combined with broader application and infrastructure support. A-listware also serves industries including fintech, payments, banking, healthcare, retail, manufacturing, real estate, transportation, and telecommunications. This makes it relevant for organizations that want code assessment as part of a broader software engineering or cybersecurity engagement.
Redwerk treats software auditing as a broader technical assessment rather than a source-only review. Its current audit offering includes SDLC, architecture, code quality, QA, and security audits. The Code Quality Audit uses static and dynamic analysis to assess maintainability, readability, technical debt, third-party integrations, APIs, external systems, and data flows. Redwerk also provides software audits involving source code, architecture, and security assessments. The company has European offices in Kyiv and Tallinn and has been developing custom software since 2005.
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Pentrox provides a security-focused source code review built around manual expert analysis. Its methodology combines automated analysis with manual examination of authentication, authorization, input validation, secrets handling, session management, dependencies, and potentially unsafe coding patterns. The company uses security guidance and references including the OWASP Code Review Guide, ASVS, and CWE Top 25, and pairs source review with web and API penetration testing to validate whether identified weaknesses are exploitable. Pentrox also provides retesting after remediation and delivers findings with code references, severity ratings, evidence, and remediation guidance.
Digital Unicorn has a dedicated code audit practice covering web and mobile applications. Its services include separate assessments for security, code quality and maintainability, and technical due diligence. The company uses static analysis, dynamic analysis, and software composition analysis as part of security-focused reviews, while quality audits examine architecture, readability, error handling, coding standards, and technical debt. Its audit work covers common languages such as Java, Python, PHP, JavaScript, TypeScript, C#, Ruby, Go, Kotlin, and Swift. Digital Unicorn is based in Paris and also provides web and mobile development services.
Choosing a code audit company in Europe depends on what needs to be assessed. Some firms focus primarily on application security and source code vulnerabilities, while others take a broader view that includes architecture, technical debt, performance, QA, and modernization. The companies on this list cover both approaches, giving businesses options for standalone code reviews as well as audits that can lead into ongoing development or remediation work.
