Conventions of URLs, Methods, and Errors: Predictable and Standardized API

Last edited:

Diana Romanova

—

June 25, 2025

URL, method, error conventions ('GET', 'POST', 'PUT', 'DELETE')

A reliable and understandable API starts with clear rules for building interfaces. We adhere to REST best practices so that each developer knows what to expect: the URL structure is logical, the methods are appropriate for the action, and the errors are easily interpreted.

This lowers the entry threshold, simplifies integrations, and allows the system to scale without chaos.

Conventions of URL and HTTP methods

Method	Appointment	Sample Query
`GET`	Getting a resource	`GET /users/42`
`POST`	Create a new resource	`POST /users`
`PUT`	Full resource update	`PUT /users/42`
`PATCH`	Partial Resource Update (Opt) `PATCH /users/42`
`DELETE`	Delete a resource	`DELETE /users/42`

Plural nouns are used ('/users', '/devices', '/games')

Nested entities are described as a hierarchy ('/users/42/sessions')
All requests go via HTTPS

Error handling standards

Code	Value	Sample message
`400`	Invalid request	`Missing required field: email`
`401`	Not authorized	`Invalid token or expired session`
`403`	Access denied	`Access denied to resource`
`404`	Not found	`User with ID 42 not found`
`409`	Conflict (e.g. duplication)	`Email already in use`
`422`	Validation error	`Field 'age' must be a number`
`500`	Internal server error	`Unexpected exception, contact support`

Error response structure:

json
{
"error": {
"code": 400,   "message": "Missing required field: email",   "details": {...}
}
}

Developer Benefits

Quick understanding of API logic without unnecessary documentation

Unified approach to all modules and entities
Easy debugging and logging thanks to standard codes and formats
Compatibility with OpenAPI/Swagger, Postman, SDK autogeneration
Simplifies support, testing, and CI/CD

Where especially important

Open or Partner API Platforms

Projects with multiple development teams
Microservices architecture or API-first approach
Systems with many entities and interactions

Uniform conventions make the API reliable, understandable and convenient. We adhere to the best REST practices so that each integration takes place quickly, without misunderstandings and with maximum predictability.