Custom API-first platform development

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What is API-first development?

API-first is a development approach in which the API is designed and defined before implementation begins. The API contract is central and determines how all components communicate with each other.

This contrasts with code-first, where you write code first and generate documentation afterwards. API-first produces consistent, well-considered interfaces that frontend and backend teams can develop in parallel.

📋
The contract as the source of truth
A single central specification from which code, documentation and tests are generated
⚡
Parallel development
Frontend and backend work simultaneously using mocks and stubs
🔄
Consistent integrations
Standardised APIs for internal and external consumers
🛠️
Custom API platform, not a standard solution

We do not sell ready-made API management platforms or gateways. Every API-first platform we build is fully bespoke, designed specifically for your domain, use cases and integration landscape. Together we determine which API styles, tooling and governance best suit you, without third-party platform licence fees.

The API-first principles we apply

Our API-first approach is based on proven principles for scalable, maintainable APIs.

01
Design before code
APIs are designed and discussed before any code is written. Changes on paper are cheaper than changes in code.
02
The contract as the single source of truth
The OpenAPI or GraphQL schema is the only source of truth. Code, documentation and tests are generated from it.
03
Consumer-driven design
APIs are designed from the perspective of their consumers, not the implementation. What do clients need?
04
Versioning from day one
Your versioning strategy is determined from the very start. Breaking changes are introduced in a controlled manner.
05
Automation everywhere
Contract validation, code generation, documentation and tests are automated within the CI/CD pipeline.
06
Developer experience first
APIs are intuitive, consistent and well documented. A good developer experience leads to faster adoption.

API-first vs code-first

Both approaches have their place, but API-first offers clear advantages for complex systems.

Aspect
API-first
Code-first
Parallel development
Yes, with mocks
No, waiting on the backend
API consistency
High (contract enforceable)
Varies by developer
Documentation quality
Always up to date
Often outdated
Breaking change detection
Automatic in CI/CD
Manual / in production
Client SDK generation
Automatic
Extra effort
Initial setup time
More upfront
Faster to start

Our API-first approach

From domain analysis to production-ready APIs, we guide you through the entire process, tailored to your needs.

1
API design workshop
We analyse your domain and use cases to determine the optimal API structure
2
Contract definition
OpenAPI/GraphQL schemas with validation, examples and comprehensive documentation
3
Parallel implementation
Backend implementation while the frontend works with mocks
4
Integration and production
Contract testing, SDK generation and rollout to production

What we build for you, bespoke

Complete API-first platforms, from design through to operational management.

📐
API design
RESTful APIs, GraphQL schemas or gRPC services designed for your specific use cases
📄
Contract management
OpenAPI specifications with versioning, validation and change tracking
🔧
Code generation
Automatic server stubs, client SDKs and type definitions generated from the contract
🎭
Mock servers
Realistic API mocks for parallel frontend development and testing
🧪
Contract testing
Automated tests that verify the implementation follows the contract
🚪
API gateway
Rate limiting, authentication and monitoring for your API endpoints

Technologies for API-first

We choose the right tools and frameworks for your specific situation.

OpenAPI / Swagger
GraphQL
gRPC / Protocol Buffers
AsyncAPI
Node.js / NestJS
Python / FastAPI
Go
Kong / Traefik
Postman / Insomnia
Spectral
Pact
Prism

Frequently Asked Questions

API-first development is an approach in which the API is designed and defined before implementation begins. The API contract (the specification) is central and determines how all components communicate with one another. This ensures consistent, well-documented APIs that can be developed in parallel by multiple teams.
With code-first, you write the code first and then generate the API documentation. With API-first, you design the contract first (in OpenAPI, GraphQL schema, etc.) and generate code, mocks and documentation from it. API-first leads to better-considered interfaces and enables parallel development.
No, we do not sell standard API platforms or frameworks. Every API-first platform we build is entirely bespoke, designed specifically for your use cases, integrations and scalability needs. We choose the right technologies and patterns for your situation.
We build APIs in different styles depending on your use case: REST for resource-based APIs, GraphQL for flexible queries, gRPC for high-performance internal communication, and WebSockets for real-time functionality. We often combine several styles within a single platform.
Yes, we help organisations move their existing code-first APIs to an API-first approach. We do this step by step: first we document the current APIs in OpenAPI, then we add contract testing, and then we refactor where necessary for consistency and better developer experience.

Related services

Discover our other custom services that complement API-first development.

Microservices architecture
Modular services with APIs
Scalable architecture
Custom cloud-native platforms
Platform engineering
Internal developer platforms
API integrations
Integrating external systems
Enterprise software
Business-critical applications
Building software
Custom software development

Ready for a custom API-first platform?

Discuss your API strategy with our specialists. We analyse your current situation and advise on the best approach, entirely without obligation and specific to your organisation.

Schedule an API conversation Email us directly

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