API Development Services
API development services for interfaces other teams can trust.
We design and build custom REST APIs, GraphQL layers, and webhook systems for product teams that need stable contracts between applications. The work includes authorization, failure handling, versioning, observability, and usable documentation, not just a set of endpoints that works in a demo.
Bring the problem, the current workflow, or the existing code. We reply with a practical next step within one business day.
Trusted by
The brief
Start with what is not working.
Good software decisions begin with the constraint, not a list of features or a preferred technology.
Are integrations slowing down because every consumer interprets the same data differently?
Do API changes reach production before documentation, permissions, and failure paths are ready?
Plain answer
API development services design and build the contracts applications use to exchange data and actions. RaftLabs delivers REST APIs, GraphQL layers, and webhook systems with authorization, versioning, failure handling, tests, observability, and documentation. The first release is scoped around one bounded domain and the consumers that depend on it.
What to remember
- Start with the contract that carries the most risk, not the interface pattern you like.
- Make ownership and failure explicit: what consumers may send, what they can expect back, and how changes are introduced.
- REST is a dependable default; GraphQL earns its place only when several clients each need a different connected slice of one domain.
- Idempotency must follow the downstream business step, not only the HTTP request.
The happy path is the smallest part of an API.
The first consumer gets a response and the integration looks finished. Then a request is retried, a field changes, a token has the wrong scope, or a downstream system times out after completing the request. Without a written contract for those cases, every consumer invents its own workaround.
A dependable API makes ownership and failure explicit. It tells consumers what they may send, what they can expect back, how changes are introduced, and what happens when part of the transaction fails.
A custom API is justified when the contract between systems is part of the product.
If the left side fits, custom development may be sensible. If the right side fits, use the vendor connector or managed backend first.
Several applications or partners need a stable interface to the same business capability.
Authorization, audit history, retries, or versioning carry real operational risk.
The underlying business rules do not fit a standard connector or managed backend cleanly.
A supported connector already covers the data and actions you need.
The source system and ownership rules are still changing every week.
You need a one-time data transfer rather than a maintained interface.
The first decision is not what to build.
It is whether software is the right answer at all. We use four possible recommendations before discussing a development scope.
Buy
Run the build-vs-buy numbersUse a supported connector or managed API product when it covers the interface and the failure semantics are acceptable.
Repair
Keep the existing API when consumers work around its gaps without incident and the change risk outweighs the benefit. Start with evidence: consumer journeys, failure examples, and what each workaround costs.
Build
Own the contract when the interface carries business risk: money movement, permissions, or downstream steps that cannot fail silently. Start with the contract that carries the most risk.
Wait
Do not design an API for consumers that do not exist yet. Name the first consumer, then write the contract it needs.
Not sure which path is yours? Bring it to a 30-minute call. Leave with the answer in writing.
Scope
What a production API needs
A contract built around consumers
Resources, queries, commands, and events reflect real consumer jobs. Schemas, validation, pagination, errors, and examples use consistent conventions so a second integration does not require a second interpretation.
Authorization at the business boundary
Authentication proves identity; authorization controls what that identity may read or change. We model roles, scopes, tenant boundaries, and sensitive fields against the business domain, then test denied paths as carefully as allowed ones.
Reliable asynchronous events
Webhook signatures, idempotency keys, retry policies, dead-letter handling, and replay tools prevent duplicate or delayed events from silently corrupting state. Operators can see which event failed and what happens next.
Versioning, documentation, and operations
OpenAPI or schema documentation lives with the implementation. Contract tests catch incompatible changes. Metrics, traces, logs, rate limits, and an ownership runbook make the API supportable after launch.
Which interface pattern fits the job?
REST, GraphQL, and webhooks
| Pattern | Use it when | |
|---|---|---|
| REST | Resource operations over HTTP | Consumers need predictable commands and broad tooling support |
| GraphQL | A typed query layer | Clients need different views of a connected domain |
| Webhooks | Event delivery to a consumer endpoint | Another system should react without polling |
| Batch or files | Scheduled bulk exchange | Volume matters more than immediate response |
The choice is not ideological. A product may expose REST for commands, GraphQL for a complex interface, and webhooks for downstream events. The web application and mobile app consuming those interfaces are separate products with their own contracts. We keep each pattern narrow enough to explain and operate.
What a production REST contract must settle
REST is a dependable default when consumers need predictable resource operations and broad tooling support. The contract still needs more than routes and verbs: an OpenAPI review, consistent status and error semantics, bounded pagination, object-level authorization, and evidence that a deprecated field can be removed without surprising consumers. Mutating requests also need idempotency that follows the downstream business step, not only the HTTP request.
When GraphQL earns its complexity
GraphQL fits when several clients need different connected views of the same domain. It is usually unnecessary for a simple single-client CRUD interface. A production GraphQL layer needs resolver batching to prevent N+1 work, query-depth or cost limits, field-level authorization, schema deprecation, and traces that expose expensive operations. Federation should follow a real ownership boundary; adding it before domains and teams are stable creates another coordination layer without solving a buyer problem.
Delivery
From API contract to supported release
Design the boundary before code makes it expensive to change.
- Phase 101
Map consumers and boundaries
Define who calls the API, which system owns each field, and what the first bounded domain must do. We record throughput, latency, compliance, and availability constraints without pretending every endpoint needs the same service level.
- Phase 202
Design the contract
Agree resources, events, permissions, error responses, idempotency rules, and versioning. Consumer examples and a contract review expose ambiguity before implementation begins.
- Phase 303
Build and test failure paths
Implement the interface, contract tests, authentication, rate limits, retries, monitoring, and documentation. Tests cover duplicates, partial failure, timeouts, and forbidden access as well as successful requests.
- Phase 404
Release and observe
Onboard the first consumers, watch latency and errors, document operational ownership, and support the production handoff. New consumers and domains follow only after the first contract holds up in use.
Where API projects usually fail
- The endpoint exists before ownership is clear
- An API cannot settle which system owns customer status, price, or entitlement. We assign a source of truth and conflict rule before exposing the field.
- Retries create duplicate actions
- Payments, orders, and jobs need idempotency and reconciliation. A network timeout does not prove the original action failed.
- Authorization stops at login
- A valid token may still belong to the wrong role, tenant, or scope. Permission tests must cover the business object, not only the gateway.
- Breaking changes arrive by surprise
- We define compatibility, deprecation, and consumer communication before the first version ships.
Proof
Relevant API delivery
- 01
Mobile POS and merchant-acquiring platform
A mobile POS product with one payment ledger across PayBy and Stripe, role-controlled GraphQL access, and payment-event processing. - 02
Legal software development case study: a Flutter conference app built on a client-owned PHP backend, still running after two years
A Flutter conference app for a Paris legal publisher, built as a pure client of a backend the client's own developer ran. Stable for two-plus years. Around 200 to 300 users, which was below expectation.- users on the product, below what we expected
- 200-300
- live on both stores without a rebuild
- 2+ years
- app-side issues after the first release
- Near-zero
- 03
Broadband customer rewards platform case study: portal SSO and fixed-fee hosting
A customer rewards platform for a full-fibre broadband provider: single sign-on from the account portal, a Vercel and Neon backend sized for a fixed monthly fee, and participation KPIs built into the admin console.- from a new codebase to a live staging environment
- 13 days
- lifetime of each signed, single-use sign-in token
- 10 s
- token transport options specified for the provider's security team to choose from
- 3
Start with the contract that carries the most risk
Bring the consumer journeys, sample payloads, current failure examples, and security constraints. We will determine whether the right first step is a custom API, a supported connector, or a narrower interface change, then define the smallest production boundary worth building. When the job is connecting applications the business already runs rather than exposing a new interface, that is business systems integration.
What it costs
Every project starts at $10000.
The first phase defines the contract that carries the most risk, with authorization, error semantics, and change rules written down before code starts.
Starting investment
Starts at $10000
Scoped per integration surface, with the contract, versioning, and failure behavior agreed in writing. After a 30-minute call, you get a written build, buy, repair, or wait recommendation plus first-phase direction. Free, whether or not you build with us.
Work with us
Bring us the integration that keeps breaking.
We will map its consumers, ownership, and failure paths, then show you the smallest API release worth building.
- The consumers, systems, and business capability the API must serve
- Existing schemas, sample payloads, or the contract that keeps changing
- Authorization, volume, compliance, and failure-recovery requirements
Common questions
A production API engagement includes contract design, implementation, authentication and authorization, validation, consistent errors, versioning, automated tests, documentation, monitoring, and a release plan. Webhooks also need signature verification, retries, idempotency, and a visible path for failed events.
REST is a strong default for resource-based operations and broad interoperability. GraphQL helps when different clients need different views of the same domain. Webhooks notify another system when an event occurs. Many products use more than one pattern, but each should solve a specific consumer need.
Yes, if the legacy system exposes a dependable database, file, procedure, or interface. An API layer can create a safer boundary for new consumers, but it does not remove unreliable data or hidden business rules underneath. We identify that boundary before recommending an API-only approach.
Version the URL, publish a deprecation timeline, and avoid removing or renaming anything inside a supported version. Versioning is a promise-keeping problem: every breaking change needs a migration path and a communication plan for the clients that depend on the old behaviour. Design the first version as if the second already exists.
The endpoints are the smallest part of the budget. Authentication that survives a security review, versioning, documentation, rate limiting, monitoring, and operational tooling are where the budget lives. An internal API costs a fraction of a partner API, which costs a fraction of a public one: the audience determines how much rigor each layer needs.
Ask any vendor about the specific failure classes: service keys shipped in browser bundles, unprotected routes, user identity taken from the caller instead of the session, and unsigned webhooks. The answers should be boring and specific: key rotation, server-enforced authorization on every route, signed webhook payloads, not a general promise of security.
You do. The code, specifications, keys, and infrastructure live in your accounts with work-for-hire IP transfer at each milestone. Insist on standard protocols and a real data export from day one: a custom query language with no export is a rewrite waiting to happen.
Read the documentation as if you were a new developer: can a competent outsider integrate without emailing anyone? Ask for a live test environment and try the core calls yourself. Require the supplier to demonstrate versioning, rate limiting, and error handling, not just the happy path. Good docs are the difference between an API people use and one they ask about.
The main scope drivers are the number of business domains and consumers, authorization depth, event volume, regulatory controls, legacy dependencies, and the stability of upstream data. We define the smallest contract that can serve real consumers and be operated safely before expanding it.