Service · App development

App second opinion: independent audit and review.

A vendor-independent assessment of your existing app or in-development project. Codebase, architecture, security and GDPR, app store readiness, cost projection, team and supplier evaluation and, since 2025, AI Act compliance. A senior Dutch team with no stake in ongoing work and no two-person sales pitch. A report you can put in front of your board or investors.

Codebase auditArchitectureSecurity & GDPRApp store readinessAI ActVendor-independent

A second opinion is not an attack on your current supplier.

Most clients who call us for a second opinion find themselves in an awkward spot. An app has been built, or is still being built, and there are signs that things aren't quite right: a release that keeps slipping three sprints, a security question from a major customer that never gets answered, an investor who wants an independent view for technical due diligence, or a newly appointed CTO who wants to understand what they're inheriting. A conversation with the current supplier tends to be predictable, since they have a vested interest in continuing the work, and internally the knowledge is often too thin to ask the right questions.

That is exactly what we are here for. We have no stake in ongoing work: if our audit concludes that your current supplier is doing sound work and simply needs sharper planning, we will say so. If it concludes that the codebase is so weak that a rebuild is cheaper than carrying on, we will say that too. We are senior Dutch engineers with years of mobile and backend experience, not a sales team quietly positioning itself for the follow-up contract. Our broader app practice is kept separate from our audit practice, so a client can commission a second opinion without any further work ever following from it, and that happens regularly.

For founders who doubt their current supplier, a second opinion turns that doubt into a factual decision. For CTOs who have just joined or who need to justify the stack to a board, it provides a neutral baseline. For investors commissioning technical due diligence, it supplies the substantive layer beneath a DD process: code quality, technical debt, vendor dependency and security risks, rather than only a financial and legal picture. And for development teams who want to know whether the quality they deliver is market-standard, it offers a quality gate that is hard to organise internally.

Every audit is confidential. We sign an NDA, hold source code and documentation only for the duration of the engagement in a secured environment, and report exclusively to the client. If you want the current supplier present at the final review, for example to agree a joint improvement plan, that can be arranged. If you would rather they were not, that is fine too.

Three types of second opinion.

The right format depends on what you need: a focused sanity check, a full audit, or technical due diligence for an investment or acquisition. In the first conversation we advise which fits best. Engagements often start lightly and grow if the signals found merit follow-up.

Compact project · fixed sprint budget

Sanity check

A focused review of a defined part of the app or project. Suited to a specific concern: "the release keeps overrunning", "the login feels slow", "we're getting GDPR questions we can't answer". We examine the codebase in that area, walk through the architecture, speak with one or two key engineers on the current team, and deliver a concise report with findings, severity classification and concrete recommendations.

Code sampleArchitecture outlineFindings + severityConcise report
Mid-sized project · fixed sprint budget

Full app audit

A complete second opinion on the app as a whole. We audit the entire codebase (iOS, Android, and where relevant cross-platform via Flutter or React Native), the backend, the CI/CD pipeline, the release processes for the App Store and Google Play, the security and GDPR position, and operational monitoring. We also evaluate the current team or supplier on pace, quality and knowledge retention. The outcome is a structured report, findings by severity level, a remediation roadmap and, if wanted, a session with the current team to launch the improvement plan.

Full codebaseArchitecture reviewSecurity & GDPRRemediation roadmap
Larger project · fixed sprint budget

Technical due diligence

A second opinion tailored to an investment, acquisition or carve-out moment. In addition to the full audit findings, you receive a cost projection for further development and maintenance, a vendor risk analysis (lock-in, key-person dependency, contractual clauses), an AI Act compliance check if the app contains AI components, and a quality gate validation against the type of buyer or investor requirements we have encountered in previous due diligence projects. The report is prepared in a form an investment committee or acquisition team can use directly.

Cost projectionVendor riskAI Act complianceInvestor-ready report

What you get at the end.

A structured report you can build on, internally or externally, whether for a board presentation, a conversation with your current supplier or an investor due diligence. Not a spreadsheet dump of loose comments, but a readable document in which severity, remediation and priority are clearly set out.

  • Structured reportExecutive summary for the board or investor, plus a technical appendix in which each finding is substantiated with code references and context.
  • Findings with severity classificationEach identified risk classified by severity (critical, high, medium, low, observation), with supporting evidence and a concrete remediation proposal per finding.
  • Remediation roadmapA prioritised approach to resolving the findings, broken down into quick wins, structural improvements and strategic reconsiderations, with a realistic scope indication for each component.
  • Architecture overviewA visual diagram of the current architecture (app, backend, external dependencies, data flows) as we found it in the codebase. Such an up-to-date picture is often missing for the client.
  • Security and GDPR positionAn assessment against OWASP MASVS and ASVS, a GDPR check of data flows and legal bases and, where relevant, a check against NEN 7510 (healthcare) or ISO 27001 requirements imposed by your clients or sector.
  • AI Act compliance check (optional)For apps with AI components, a review against the relevant articles of the EU AI Act, in particular Articles 9 to 15 on risk management, transparency and human oversight.
  • Further development cost projectionA realistic estimate of what it will cost to close the identified gaps and continue developing the app to a healthy standard, regardless of who carries out that work.
  • Team or supplier evaluationAn factual assessment of your current development team or supplier in terms of pace, quality of delivery, knowledge retention and collaboration, without value judgements where there is no evidence to support them.
  • Closing session (optionally with your current supplier)A session in which we explain the findings, either with you alone, with your internal team, or with your current supplier present to draw up an improvement plan together.

When a second opinion makes sense.

Six patterns we see again and again. If you recognise your situation in one of them, we are happy to talk it through, even if you are not yet sure whether an external audit is the right answer.

Founder · doubt

Doubts about your current supplier

Releases keep running late, communication becomes strained, or bugs keep piling up without being fixed structurally. An independent audit brings clarity: is it down to scope, the team, the codebase, or a combination of these? With that answer you can have a factual conversation with your supplier instead of a sentiment-driven discussion that goes nowhere.

CTO · take-over

New CTO or tech lead

You have just joined and within three months you need to explain to the board what you have taken over: where the codebase stands, what technical debt it carries, which security and compliance risks we run, and what a sensible development path forward would look like. An external audit gives you that picture without you having to identify every hot potato yourself.

Investor · DD

Technical due diligence for investment

A VC or strategic buyer commissions a DD on a target whose core product is an app. Alongside the financial and legal DD, a substantive technical layer is needed: code quality, scalability, technical debt, key-person dependency and vendor risk. We deliver that layer in a form that fits straight into the DD file.

Pre-launch · quality gate

Quality gate before launch

The app is about to go live, and before launch you want an independent check on security, performance, app store readiness and operational readiness. Not an extra developer on the team, but a neutral gate that tells you: this is ready for production, or: these three things need to be fixed first. It complements your own team's quality work.

Compliance · audit

Compliance or security request from a client

An enterprise client or regulator asks for demonstrable security and compliance: a SOC 2 process, an ISO 27001 audit, or a DPIA for a use case involving sensitive data. Our audit gives you a starting position and an improvement plan, so the external process does not open with too many surprises.

AI · review

AI components in the app

The app contains an LLM integration, a proprietary model, an agent loop or a recommendation algorithm, and you want to know whether it has been set up in line with the EU AI Act and whether there are practical risks around privacy, prompt injection, data retention or exposure to hallucinations. This review is often carried out together with our AI consultancy practice.

How a second-opinion engagement works.

1

Introduction and scoping

A conversation in which we go through your situation, the signals you are seeing and what you hope to achieve with the audit. We discuss practical matters: which format suits (a sanity check, a full audit or a technical DD), what the scope of the codebase is, whether the current supplier is aware, and how confidentiality will be handled. Outcome: a clearly defined assignment with a fixed price and timeline, and an NDA if one is not yet in place.

2

Access and familiarisation with materials

We are given read access to the codebase (Git repository), the architecture documentation if it exists, the CI/CD pipeline, monitoring dashboards and, where available, existing security reports. For in-development engagements, we also get access to the backlog and sprint rituals. If wanted, we speak with one or two key engineers on the current team for context, not to pass judgement on them but to read the codebase more quickly.

3

Audit work

The substantive phase. Static code analysis, manual review of critical modules, architecture walkthrough, dependency scanning, security review against OWASP MASVS and ASVS, GDPR check on data flows, evaluation of the CI/CD pipeline and release processes, and an AI Act check where applicable. For compliance-heavy work we use frameworks that match your situation: a fintech app gets a different lens from a healthcare app, for which we often draw on ISO 27001 principles and NEN 7510.

4

Reporting and remediation roadmap

We prepare the report with an executive summary, findings by severity, a remediation roadmap, a cost projection and, depending on scope, a vendor risk analysis and AI Act findings. We first discuss the draft with you internally, so that we can correct factual inaccuracies or missing context before the report is finalised. For security background, you can use our guide to app security as a reference for your internal team.

5

Final discussion

A session in which we walk you through the findings verbally, either with you alone, with your internal team or, if you prefer, with your current supplier present. In the latter case we moderate the conversation so it stays constructive and ends with a concrete follow-up plan both parties can support. For strategic follow-up questions, such as whether to replace the supplier, bring development in-house or rebuild the app, we can continue in a digital consulting engagement, or simply send you on your way with a clear picture.

Frequently asked questions.

What clients typically want to know before we start a second opinion.

How does a second opinion stay genuinely independent?
Through our structure and our approach. Our audit practice is separate from our app development practice: the senior engineer who carries out your audit has no sales target tied to a follow-on project and is not assessed on one. We are also transparent about potential conflicts of interest: if we have ever worked with your current supplier before, or if we are a direct competitor of that supplier for other clients, we disclose this before the engagement starts. In practice, for many clients the audit leads to an improvement plan with the current supplier rather than a switch. That is fine by us, and in fact the most common outcome.
Which frameworks and standards do you use?
It depends on the scope. For mobile security we use the OWASP MASVS (Mobile Application Security Verification Standard), and the ASVS for the backend. For general information security we use ISO 27001 as a framework. For healthcare apps we use NEN 7510 and the related DPIA requirements. For AI components we apply the relevant articles of the EU AI Act, in particular Art. 9 (risk management), Art. 10 (data governance), Art. 13 (transparency) and Art. 14-15 (human oversight and cybersecurity). For app store readiness we follow the current Apple App Store Review Guidelines and Google Play Policies. We update these for each audit, as they change several times a year.
What do you need from us to get started?
Read access to the Git repository containing the app and backend code, any architecture documentation, access to the CI/CD environment (read-only is sufficient), visibility into the App Store Connect and Google Play Console accounts or an export of these, and, for projects still in development, access to the backlog and the latest sprint overviews. For security work we also ask for any previous penetration test reports or security audits, to avoid duplicate effort. We sign an NDA before the engagement starts; many clients use our NDA template, others use their own.
Can the current supplier know that we are looking?
That is up to you. Some clients inform their supplier openly and actively ask for cooperation. This gives us access to context we would otherwise have to reverse-engineer, and it often speeds up the work. Other clients prefer to keep the audit confidential at first, particularly where they are weighing up a decision or are still deciding on further investment. Both routes work, with different implications for pace and depth. We will discuss which route suits your situation during the introductory conversation.
Can you also audit projects that are still in development?
Yes, that is a common question. For an in-development audit we look not only at the code that exists, but also at the backlog, the architectural choices still to be made, the sprint cadence and the agreements between you and the supplier. We often identify early risks that would otherwise only surface later: a scalability choice that works for ten users but not for ten thousand, a security architecture that cannot withstand the type of integration that is coming, or a release pipeline that is not ready for the first store submission. The earlier in the project, the cheaper the correction.
What if we find that the current supplier is indeed underperforming?
That is what we say: with reasoning for each finding, and a prioritised list of what needs to change to move forward. Sometimes that is an improvement trajectory with the same supplier, for example bringing in a senior architect, changing the sprint cadence, or introducing a quality gate that we describe. Sometimes it is a change of supplier or a hybrid set-up. We do not make a recommendation to pull your follow-on project towards us; we describe what needs to happen and you choose who does it. In a number of cases, incidentally, the finding is that the supplier does good work but that scope or communication is the problem. We see that often too.
Do you also do pen tests or certifications?
We do not carry out pen tests ourselves. For those we work with specialised Dutch pen-testing firms that we have known for some time. We can include one in the remediation roadmap, or integrate the outcome of an earlier pen test into our audit. Certifications (ISO 27001, SOC 2, NEN 7510) are handled by accredited auditors. We deliver the preparatory work and the remediation approach that make a certification achievable, but not the certification itself. That is a deliberate separation, so that independence is preserved.
What about AI Act compliance in an app?
For apps with AI components, we look at the risk level of the application (prohibited, high-risk, limited-risk or minimal-risk under the AI Act), the set-up of risk management under Art. 9, the data governance under Art. 10, the transparency requirements towards end users under Art. 13, and the requirements for human oversight and cybersecurity under Art. 14–15. For a recommendation app in a retail context, the picture differs from a diagnostic-support app in healthcare, so we determine the applicable regime per use case. For the strategic side of AI decisions, we often refer you on to our AI consultancy.
Do you also work for parties outside the Netherlands?
We mainly work for clients in the Netherlands and the Benelux, because we value short physical distance for the final discussion and any on-site sessions. For pan-European clients with a Dutch entity we do carry out audits; we deliver our reports in Dutch or English, depending on who will read them. For assignments entirely outside the EU, we refer you to partners who specialise in those markets.
Who sits at the table for the final discussion?
Basically: you, or the stakeholder who requested the audit. If you want your internal team involved, such as the CTO, lead engineer or product owner, of course. If you would like the current supplier present for a joint improvement plan, that is also possible; we then moderate the conversation so that it stays constructive. For investor due diligence, an investment committee or deal team is often in attendance. We adapt the tone of the discussion to the audience: a conversation with technical people looks different from one with a board.
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Talk to us about your second opinion.

A free, no-obligation half-hour introductory call. Tell us what's going on: the warning signs that worry you, the stakeholder who will be reading the report, or the scope of the app we need to take a critical look at. We'll think it through with you, offer direction, and be honest about whether a second opinion is the right first step in your situation, or whether you actually need a different kind of conversation. You're also welcome to email us directly at fabian.vandijk@appfront.nl, or take a look at our other app development service pages for related mobile solutions.

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