Backend & API Manual

From HTTP fundamentals to scalable architecture and database lifecycles. The definitive logic reference for full-stack engineers.

HTTP Methods

GET

Retrieve Resources

Requests a representation of the specified resource. Requests using GET should only retrieve data and have no other effect.

Implementation / Pattern

GET /api/v1/users

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POST

Create Resources

Submits an entity to the specified resource, often causing a change in state or side effects on the server.

Implementation / Pattern

POST /api/v1/users
{
  "name": "Nexsa User"
}

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PUT

Replace Resources

Replaces all current representations of the target resource with the request payload (Idempotent).

Implementation / Pattern

PUT /api/v1/users/1

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PATCH

Partial Update

Applies partial modifications to a resource.

Implementation / Pattern

PATCH /api/v1/users/1
{
  "status": "active"
}

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DELETE

Remove Resources

Removes the specified resource from the server.

Implementation / Pattern

DELETE /api/v1/users/1

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Status Codes

200 OK

Success

The request has succeeded. Standard response for successful GET/PUT.

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201 Created

Success

Request fulfilled and a new resource was created. Common for POST.

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400 Bad Request

Client Error

Server cannot process request due to client error (e.g. malformed JSON).

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401 Unauthorized

Client Error

Authentication is required and has failed or has not yet been provided.

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403 Forbidden

Client Error

Client has permission to access but server refuses. (e.g. insufficient role).

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404 Not Found

Client Error

The requested resource could not be found but may be available in the future.

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429 Too Many Requests

Client Error

The user has sent too many requests in a given amount of time (Rate Limiting).

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500 Internal Error

Server Error

A generic error message when an unexpected condition was encountered.

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Common Headers

Content Types

MIME Types

Defines the nature of the data being sent in the request or response.

Implementation / Pattern

application/json
multipart/form-data
text/html

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Mastering the HTTP Protocol

Communication is the core of the modern web. Understanding the nuances of HTTP status codes and header semantics is critical for building resilient, self-documenting APIs that both machines and developers can understand.

Expert Implementation

Idempotency & Method Semantics

Web development often overlooks the difference between `PUT` and `PATCH`, or the importance of idempotency in `DELETE` operations. Our reference hub clarifies these standards to ensure your backend architecture remains consistent with world-class engineering patterns.

Protocol Specs

StandardRFC-9110-Compliant

CORSFull-Header-Logic

TypeREST-GraphQL-Ready

API Development FAQs

What is the difference between 401 and 403?

401 (Unauthorized) means the server doesn't know who you are. 403 (Forbidden) means the server knows who you are but you don't have permission for this specific resource.

When should I use a 201 status?

Use `201 Created` specifically after a `POST` or `PUT` request that successfully results in the creation of a new resource. It should usually include a `Location` header.

Are HTTP headers case-sensitive?

No. According to the HTTP specification, field names are case-insensitive. However, standard practice is to use Pascal-Case (e.g., `Content-Type`).

Why use the OPTIONS method?

OPTIONS is primarily used by browsers for 'preflight' requests in CORS. It checks which methods and headers the server allows before sending the actual data.