Undocumented endpoints
Consumers learn the API by reading code or asking developers, which slows every integration.
Custom Software · APIs
API development services with contracts your consumers can rely on
We design and build APIs for mobile apps, web frontends, partners and internal systems, starting from the contract, documenting it in OpenAPI, and versioning it so the people who depend on it get notice before anything changes.
What is API Development?
API development services cover the design, build, documentation and operation of application programming interfaces: the defined endpoints through which other software reads and changes your data. A well-built API has a clear contract, consistent naming and errors, authentication and authorization, versioning rules, and documentation that lets a developer integrate without asking questions. It becomes a long-lived product in its own right, often outliving the applications that first used it.
APIs are often built as a side effect of a frontend: endpoints added whenever a screen needs data, with inconsistent names, ad hoc error formats and no documentation. That works until a second consumer arrives (a mobile app, a partner, a new frontend) and every change risks breaking someone. Designing the API deliberately, as a contract, makes it something other teams and businesses can build on safely.
Why APIs become hard to work with
Breaking changes
A field renamed for one app breaks another, because there is no versioning or deprecation policy.
Inconsistent design
Different naming, pagination and error formats across endpoints make the API harder to use and to test.
Weak access control
Authorization checked in the frontend rather than the API, leaving data exposed to anyone who calls endpoints directly.
Our API Development service
API design & contract
Resource modeling, endpoint design, request and response schemas and error conventions, agreed with consumers before implementation.
REST or GraphQL implementation
REST for broad compatibility and caching, GraphQL where clients need flexible queries, chosen per use case and built in Node.js or Python.
Authentication & authorization
OAuth 2.0, API keys or JWT-based access, with scopes and per-resource permission checks enforced on the server.
Versioning & deprecation policy
A written approach to versions, backward-compatible changes and deprecation notices, so consumers can plan upgrades.
Documentation & developer experience
OpenAPI specifications, interactive reference docs, example requests and a sandbox environment for integrators.
Testing, monitoring & performance
Contract and integration tests, rate limiting, caching, request logging and dashboards for latency and error rates.
Included capabilities
- OpenAPI 3 specification
- Consistent error format and status codes
- Cursor or offset pagination
- Filtering, sorting and field selection
- OAuth 2.0 and scoped API keys
- Rate limiting and quotas
- Webhooks for event notifications
- Idempotency keys for safe retries
- Sandbox environment for integrators
- Automated contract tests in CI
What API Development changes for your business
Faster integrations
Good documentation and a sandbox let consumers integrate without long back-and-forth.
Changes without breakage
Versioning and contract tests catch breaking changes before they reach consumers.
One source of business logic
Rules live in the API, so every app and partner gets the same behavior.
A platform for growth
A stable API lets you add new apps, partners and channels without rebuilding the backend.
Where it makes the biggest difference
Backend for mobile and web apps
One API serving a web frontend and iOS and Android apps, with consistent data and business rules.
Partner and customer APIs
Giving distributors, resellers or customers programmatic access to orders, stock, pricing or status.
Exposing a legacy system
A modern API layer in front of an older database or application, so new software can use it without touching the core.
Internal service APIs
Clear contracts between internal systems so teams can change their own services without breaking each other.
Contract first, code second
Consumers can start building against a mock of the API before the implementation is finished.
Identify consumers
List who will call the API (apps, partners, internal services) and what each needs.
Design the contract
Draft resources, endpoints and schemas in OpenAPI and review them with consumer teams.
Mock & validate
Publish a mock server from the spec so frontend and partner work can begin in parallel.
Implement
Build endpoints against the contract with authentication, validation and business logic.
Test
Unit, integration and contract tests, plus load testing on the busiest endpoints.
Document & release
Publish reference docs, examples and a changelog; deploy with monitoring in place.
Operate & evolve
Track usage and errors, add features in backward-compatible ways and manage deprecations.
What it connects to
API Development
- Web and mobile frontends
- Partner and customer systems
- ERP platforms including Odoo
- API gateways
- Identity providers for OAuth
- Message queues and event streams
- Monitoring and logging services
Built with
REST or GraphQL?
| Criterion | REST | GraphQL |
|---|---|---|
| Query flexibility | Fixed responses per endpoint | Clients request exactly the fields they need |
| HTTP caching | Straightforward | Needs extra tooling |
| Tooling and familiarity | Universal | Widely supported, steeper learning curve |
| Versioning | Explicit versions in URL or header | Usually evolves a single schema with deprecations |
| Best fit | Public and partner APIs, simple resources | Complex frontends needing data from many related resources |
Security, quality and scale
Server-side authorization
Every request is checked against the caller's identity, scopes and the specific resource requested.
Input validation
Requests are validated against the schema, rejecting malformed or unexpected data before it reaches business logic.
Abuse protection
Rate limiting, quotas and request size limits protect the API and its downstream systems.
Encrypted transport and secrets
HTTPS-only endpoints, short-lived tokens and API keys stored hashed, with credentials kept out of source code.
What working with us looks like
Contract-first by default
We agree the API design with its consumers before writing implementation code.
Documentation is part of the deliverable
Every API we build ships with an OpenAPI specification and readable reference docs.
We build both sides
We also build the web and mobile apps that consume APIs, so we design for real client needs.
Pragmatic technology choices
REST or GraphQL, Node.js or Python: we choose for your use case and explain the trade-offs.
What it costs
Fixed-price packages with the scope written down, paid stage by stage. Your project goes live once it's fully paid.
Related services, technologies and industries
Sources and further reading
Official documentation and guidance if you want to read more about this topic.
API Development: questions we hear most
Should our API be REST or GraphQL?
REST is the safer default for public and partner APIs because it is universally understood and easy to cache. GraphQL is a good choice when your own frontends need to fetch many related resources flexibly in one request.
How do you handle API versioning?
We prefer backward-compatible changes (adding fields and endpoints rather than changing them) and introduce a new version only for genuinely breaking changes. Deprecated versions get a documented notice period so consumers can migrate.
Do you provide API documentation?
Yes. Every API ships with an OpenAPI specification, generated reference documentation, example requests and, where useful, a sandbox environment for integrators to test against.
How is API access secured?
Access is controlled with OAuth 2.0, JWTs or scoped API keys depending on the consumers, and every request is authorized on the server against the caller's permissions. Rate limiting and input validation add further protection.
Can you build an API on top of our existing system or database?
Yes. We can add an API layer in front of an existing application or database so new apps and partners can use it, without changing the legacy core more than necessary.
What affects the cost of API development?
Cost depends on the number of resources and endpoints, the complexity of business rules and permissions, performance requirements, the number of consumers to support and documentation needs. We estimate after the design phase.
Next step
Start with the API contract
Tell us who needs to use your API and what they need to do. We'll propose a design you can review before any code is written.