api-testing

API Testing

Overview

API testing verifies HTTP endpoints directly without a browser or UI layer. It validates request/response contracts, status codes, headers, payloads, authentication, and error handling at the transport level. API tests are faster than E2E tests and provide high confidence that your services behave correctly.

Cross-Platform Tools

Tool	Type	Strengths
.http files	VS Code REST Client / JetBrains HTTP Client	Version-controlled, inline in IDE, variable support
Bruno	Desktop + CLI	Git-friendly .bru collections, open source, no cloud sync required
Postman / Newman	Desktop + CLI	Rich GUI, team collaboration, extensive scripting, CI via Newman
k6	CLI (JavaScript)	Scripted API tests with checks and thresholds, doubles as load tool
REST Client (VS Code)	VS Code extension	Lightweight, .http/.rest files, inline responses

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.http Files (VS Code REST Client / JetBrains HTTP Client)

Syntax Overview

The .http file format is supported by both VS Code REST Client and JetBrains HTTP Client with minor differences. Requests are separated by ###.

Example: requests.http

### Variables
@baseUrl = https://api.example.com
@authToken = Bearer {{$dotenv AUTH_TOKEN}}

### GET — List users
GET {{baseUrl}}/users?page=1&limit=10
Authorization: {{authToken}}
Accept: application/json

### POST — Create a user
POST {{baseUrl}}/users
Authorization: {{authToken}}
Content-Type: application/json

{
    "name": "Jane Doe",
    "email": "[email protected]",
    "role": "admin"
}

### PUT — Update user
PUT {{baseUrl}}/users/42
Authorization: {{authToken}}
Content-Type: application/json

{
    "name": "Jane Smith"
}

### DELETE — Remove user
DELETE {{baseUrl}}/users/42
Authorization: {{authToken}}

Environment Files

Create environment-specific variable files for VS Code REST Client:

// .vscode/settings.json
{
    "rest-client.environmentVariables": {
        "$shared": {
            "version": "v1"
        },
        "development": {
            "baseUrl": "http://localhost:3000",
            "authToken": "dev-token-123"
        },
        "staging": {
            "baseUrl": "https://staging-api.example.com",
            "authToken": "staging-token-456"
        },
        "production": {
            "baseUrl": "https://api.example.com",
            "authToken": "prod-token-789"
        }
    }
}