Architecture consulting
Technical architecture consulting for mobile apps and their backends
Architecture mistakes are cheap to fix on a whiteboard and expensive to fix in production. Our technical architecture consulting gives CTOs, founders and product teams an outside review of a planned or existing system: mobile app structure, APIs, data, security and hosting. You get a written assessment, a risk register and architecture decision records your team can act on. It is part of our mobile app consulting work, delivered by engineers who build and run apps every week.
- Review of a plan or a live system
- Security checked against OWASP MASVS
- Decisions written as ADRs
- Fixed scope, no build commitment
When technical architecture consulting pays off
Most teams call us at one of four moments. Before a build, when a vendor has proposed a stack and you want an independent check. Before scaling, when a pilot worked and you are about to add many more users, markets or features. After an incident, when an outage or security finding has shaken confidence. And before an investment or acquisition, when someone needs technical due diligence in writing.
The common thread is a decision that is hard to reverse. Choosing a database, an auth provider or a sync model locks in cost and effort for years. A short review costs little next to a migration later.
It is less useful when the product itself is still uncertain. If you do not yet know who the users are or which features matter, start with app idea validation and discovery; architecture follows the product, not the other way round.
What an architecture review covers
We scope each review to the questions you need answered, but most cover these areas. Each finding is rated by severity and effort to fix.
| Area | What we look at | Typical findings |
|---|---|---|
| App structure | Layering, state management, module boundaries, navigation, dependency injection | Business logic inside UI code; one giant module that blocks parallel work |
| Data and offline | Local storage, caching, sync and conflict handling, migrations | No migration strategy; sync on a deprecated service such as MongoDB Atlas Device Sync |
| APIs | Contract design, versioning, pagination, error format, backend-for-frontend needs | Breaking changes shipped without versions; chatty screens that call many endpoints |
| Auth and identity | Login flows, token handling, session expiry, social login rules | Tokens in plain storage; embedded web views for OAuth |
| Backend and hosting | Services, database choice, queues, scaling limits, backups, regions | Single database with no read replicas or backups tested; no staging environment |
| Release and operations | CI/CD, signing, environments, monitoring, crash reporting, alerts | Manual releases from one laptop; no alert when error rates jump |
| Store and platform rules | Current SDK targets, billing library versions, privacy manifests | Android target below API 36; old Play Billing Library |
Reviews can include a code walkthrough or be based on documents and diagrams alone. Code access gives more reliable findings.
Scalability: what actually breaks first
Mobile apps rarely fail to scale because of the app itself. They fail at the backend: a database without the right indexes, an endpoint that loads a full list on every screen, a push job that sends to every device in one loop, or a third-party API with a rate limit nobody checked. We look for those first.
Our method is simple. We list the key user actions, estimate how many happen per minute at your target scale, and trace each one through the system to find the slowest or most limited part. That turns a vague worry about scale into a short list of specific limits, each with a fix and a cost.
Checks we run on most systems
- Database queries for the busiest screens, with indexes and query plans.
- Rate limits and quotas on external services. For example, Google’s Play Integrity API has a default quota of 10,000 requests a day per app, which you must ask to raise before a large launch.
- Background jobs, queues and retry rules for push, email and payments.
- Caching on the device and at the edge, and what happens when the cache is stale.
- Cost per active user at today’s scale and at the target scale.
Backend choices are covered in depth by our mobile app backend development team and in our guide to the best backend for mobile apps.
Security architecture reviewed against OWASP standards
We review security at the design level using the OWASP MASVS, which groups mobile controls into eight areas: storage, cryptography, authentication, network, platform, code, resilience and privacy. The OWASP Mobile Top 10 (2024) is our checklist for the most common real-world risks, with improper credential usage and inadequate supply chain security at the top.
Design-level questions are where most security debt starts. Where are secrets kept? Does the app use the system browser and PKCE for OAuth, as RFC 8252 requires for native apps? Does the server check that requests come from a genuine app, using Apple App Attest and the Play Integrity API? Are Supabase tables protected by Row Level Security, which Supabase says to enable on every table in an exposed schema?
An architecture review flags these risks; it is not a penetration test. For hands-on testing of a built app, our mobile app security testing service runs the checks.
Security questions we always ask
- Where do API keys and tokens live?
- Is OAuth done in the system browser with PKCE?
- Can the server tell a real app from a script?
- Is every exposed table access-controlled?
- Which SDKs collect user data, and why?
About to commit to a stack or scale a pilot?
Tell us what you are building, the decision in front of you and your timeline. We sign an NDA first, then reply within one business day with a proposed review scope.
Build vs buy: how we decide component by component
Most apps should buy more than their founders expect and build less. The test is whether a component is part of what makes your product different.
| Component | Usually buy or use a service | Build when |
|---|---|---|
| Authentication | Firebase Authentication, Supabase Auth, or a managed identity provider | You have unusual enterprise SSO, offline login or regulatory needs no provider meets |
| Payments | Stripe or local gateways; store billing for digital goods | Almost never; build the flow, not the processor |
| Chat and video | A specialist SDK | Messaging is the core product and SDK pricing breaks your unit economics at scale |
| Push notifications | FCM and APNs, or a service such as Azure Notification Hubs | You need delivery logic the services cannot express |
| Search | Database full-text search or a hosted search service | Ranking is a core differentiator |
| Admin panel | A framework-based panel for simple data | Operations staff run the business from it every day; see admin panel and dashboard development |
| Core domain logic | Rarely available off the shelf | Always; this is what you are building |
For every bought component we note the exit route: how hard it would be to switch provider if price or terms change.
Architecture decision records (ADRs)
The most useful thing we leave behind is often the simplest: a set of short architecture decision records. Each ADR is a one-page document in your repository that states the context, the decision, the options considered and the consequences. New developers read them to understand why the system looks the way it does. Future teams use them to know which decisions are safe to revisit.
What an ADR from us contains
- Title and status: for example “Use Room with an explicit sync API for offline data”, marked proposed, accepted or superseded.
- Context: the problem, constraints, scale and deadlines that shaped it.
- Options considered: usually two to four, each with costs and risks.
- Decision: what we chose and the main reason.
- Consequences: what becomes easier, what becomes harder, and what would trigger a review.
We write ADRs as Markdown in the repository so they stay next to the code and go through the same review as any change. They also make handovers to another team much less painful, a lesson we learn repeatedly in legacy app modernization work.
How a technical architecture consulting engagement runs
Scoping call and NDA
A 30-minute call on the decision, the system and what you need to walk away with. NDA signed before any documents or code are shared.
Fixed proposal
Written scope listing the questions, the areas under review, deliverables, duration and price.
Evidence gathering
Read access to repositories, diagrams, cloud consoles and monitoring, plus interviews with your engineers.
Draft findings
A current-state diagram, findings by severity and effort, and draft ADRs. You review and challenge them in a working session.
Final report and roadmap
Final documents, a target architecture and an ordered list of changes. Optional follow-up sessions as your team works through it.
Who we are a good fit for
We are a good fit for teams building mobile apps with a typical cloud backend: native iOS and Android, Flutter or React Native, with Node.js, Laravel, Firebase, Supabase or similar behind them. We can review your AWS or Google Cloud setup at the level a mobile product needs.
We are a weaker fit for large enterprise integration programmes, where a specialist in your ERP or core banking platform should lead and we contribute the mobile view. If your question is mainly about which vendor to hire, our checklist on how to choose an app development company may be all you need.
Architecture reviews we have run
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Technical architecture consulting: frequently asked questions
What is included in a mobile app architecture review?
Usually app structure, data and offline handling, API design, authentication, backend and hosting, release pipeline and store compliance. Each finding is rated by severity and effort, and you receive a current-state diagram, a risk register, architecture decision records and a target architecture with ordered next steps. The exact areas depend on the scope we agree.
What is an architecture decision record?
An ADR is a short document that records one significant technical decision: the context, the options considered, what was chosen and the consequences. ADRs live in your repository next to the code, so future developers understand why the system looks the way it does and which decisions are safe to change.
Is an architecture review the same as a security audit?
No. An architecture review checks security at the design level against OWASP MASVS and the OWASP Mobile Top 10: where secrets live, how auth works, whether requests are verified. A security test probes a built app hands-on for vulnerabilities. Many clients do the review before building and the security test before launch.
Can you review an architecture before anything is built?
Yes, and it is often the cheapest time. We review the proposed stack, diagrams and requirements, test them against your expected scale, budget and compliance needs, and record the main choices as ADRs. Changing a plan on paper costs a fraction of migrating a live system later.
Do you provide technical due diligence for investors?
Yes. For due diligence we review code, architecture, security posture, release process, ownership of code and store accounts, and key-person risk, then write a report for a non-technical reader with findings ranked by severity. We disclose any conflict of interest, such as having built the product ourselves.
Do we need to hire you to build after the review?
No. The review is a fixed-scope engagement and the deliverables are yours to use with your own team or any vendor. We can help implement the changes if you want, but the report is written so that any competent team can act on it.
Make your next architecture decision on paper first
Book a 30-minute call. Tell us about the system and the decision you face, and we will send a fixed review scope in writing.