API-first architecture: why every business system should start here

What API-first means

API-first design starts with the interface between systems before building any UI or business logic. Every feature is accessible through a documented API endpoint, making the system inherently:

• Integrable with any other system
• Testable at every layer
• Scalable by adding capacity to specific endpoints
• Future-proof because the frontend can be replaced without touching business logic

API design principles we follow

1. RESTful resource naming

Every endpoint represents a business resource:

• GET /api/v1/clients returns a list of clients
• GET /api/v1/clients/:id returns a specific client
• POST /api/v1/clients creates a new client
• PUT /api/v1/clients/:id updates a client
• DELETE /api/v1/clients/:id removes a client

2. Versioned endpoints

Always version your API (/v1/, /v2/). This allows you to evolve the API without breaking existing integrations.

3. Consistent error responses

Every error returns the same structure:

{
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Email address is required",
    "field": "email"
  }
}

4. Pagination and filtering

List endpoints support standard pagination:

• ?page=1&limit=20 for offset pagination
• ?cursor=abc123&limit=20 for cursor pagination
• ?filter[status]=active for filtering
• ?sort=-createdAt for sorting

5. Rate limiting and throttling

Protect your API and your users:

• Standard rate limits (100 requests/minute for authenticated users)
• Burst allowance for legitimate spikes
• Clear rate limit headers in every response
• Graceful degradation, not hard failures

When to use GraphQL instead

GraphQL is the better choice when:

• Clients need flexible data shapes (mobile vs web)
• You have deeply nested data relationships
• Bandwidth is a critical concern (mobile apps)
• Multiple teams consume the same API with different needs

REST is the better choice when:

• You need caching at the HTTP level
• Your data model is flat and resource-oriented
• You want maximum ecosystem compatibility
• API consumers are external partners or third parties

Documentation as a deliverable

Every API we build ships with:

• Interactive API documentation (Swagger/OpenAPI)
• Authentication guide with code examples
• Webhook documentation with payload samples
• SDK or client library for common languages
• Postman collection for manual testing

Good documentation reduces integration time by 70% and support tickets by 50%.