Difference Between POST vs GET Requests

HTTP Method Definitions: GET vs POST

• GET: Requests a representation of a resource. It’s a read-only operation with no server-side changes.
• POST: Submits data to a resource for processing, often altering the server’s state.

Technical Breakdown: How GET and POST Work

Request Structure

GET /api/users?id=123 HTTP/1.1  
Host: example.com

• Data lives in the URL as a query string (?id=123).
• Headers are minimal no body unless the server misbehaves (which violates spec).

POST /api/users HTTP/1.1  
Host: example.com  
Content-Type: application/json  
Content-Length: 27

{"name": "John", "age": 30}

• Data resides in the request body.
• Headers like Content-Type and Content-Length describe the payload.

Key Properties

• Idempotency: GET can repeat without side effects. POST might duplicate records.
• Safety: GET doesn’t modify; POST does.
• Caching: GET leverages browser and proxy caches. POST doesn’t.

Performance Implications

Caching and Speed

POST /api/products/search HTTP/1.1  
Host: example.com  
Content-Type: application/json

{"category": "electronics"}

Payload Size

Security Considerations

Data Exposure

GET /api/login?username=john\&password=secret HTTP/1.1

POST /api/login HTTP/1.1  
Content-Type: application/json

{"username": "john", "password": "secret"}

CSRF Risks

<form action="<https://example.com/api/transfer>" method="POST">  
  <input type="hidden" name="amount" value="1000">  
  <input type="hidden" name="to" value="attacker">  
</form>

Real-Life Scenarios: GET vs POST

Scenario 1: Fetching a User Profile

GET /api/users/123 HTTP/1.1  
Host: example.com

• Why GET? Read-only, cacheable, simple ID in URL.
• Outcome: Fast, repeatable, leverages caching.

POST /api/users/get HTTP/1.1  
Host: example.com  
Content-Type: application/json

{"user_id": 123}

• Why Not? Non-cacheable, unnecessary complexity for a read.

Scenario 2: Submitting a Form

POST /api/users/register HTTP/1.1  
Host: example.com  
Content-Type: application/json

{"username": "jane", "email": "jane@example.com"}

• Why POST? Creates a resource, hides sensitive data, supports large payloads.
• Outcome: Secure, reliable state change.

GET /api/users/register?username=jane\&email=jane@example.com HTTP/1.1

• Why Not? Exposes data, violates idempotency.

Scenario 3: Searching with Filters

GET /api/products?category=books&sort=price HTTP/1.1

• Why GET? No state change, cacheable, shareable URL.
• Outcome: Efficient, user-friendly.

POST /api/products/search HTTP/1.1  
Content-Type: application/json

{"category": "books", "sort": "price"}

• Why Not? Loses caching, overcomplicates a read.

Tooling: Testing GET and POST Requests

ApyHub

• GET: Test endpoints like /validate/email?value=test@example.com from its catalog.
  
• POST: Use pre-built APIs (e.g., PDF generation) with body payloads.
  
• What We Like: 130+ ready-to-use APIs, cuts dev time, production-grade.
  
• What We Don’t Like: Less flexibility for custom endpoints.

Postman

• GET: Enter a URL with query params, hit send. Visualize cached responses with headers like ETag.
• POST: Build JSON payloads, tweak headers, and test non-idempotent calls.
• What We Like: Intuitive UI, history tracking, mock servers.
• What We Don’t Like: Overkill for quick tests; free tier limits collaboration.

cURL

• GET:

    curl -X GET "<https://example.com/api/users?id=123>"

• POST:

curl -X POST -H "Content-Type: application/json" -d '{"name":"John"}' <https://example.com/api/users>

• What We Like: Lightweight, scriptable, no GUI bloat.
• What We Don’t Like: Verbose for complex payloads; no native visualization.

Insomnia

• GET: Similar to Postman, with URL-based params and response previews.
• POST: Drag-and-drop file uploads, easy body formatting.
• What We Like: Clean design, Git sync for teams.
• What We Don’t Like: Lacks Postman’s ecosystem (e.g., mocks).

Best Practices for GET and POST

• GET:
  • Use for reads only.
  • Keep URLs short; avoid sensitive data.
  • Enable caching with Cache-Control.
• POST:
  • Use for creates/updates.
  • Add CSRF tokens.
  • Validate payloads server-side.
• General:
  • Stick to REST semantics (GET for fetch, POST for create).
  • Always use HTTPS.

Common Pitfalls and Misconceptions

1. “GET Can’t Handle Data”: It can, but URL limits apply. POST scales better.
2. “POST is Secure”: Only with HTTPS otherwise, it’s as exposed as GET.
3. “Use GET for Everything”: Breaks HTTP rules, kills caching, risks security.

Advanced Use Cases

GET with Pagination

GET /api/posts?page=2&limit=10 HTTP/1.1

• Why? Efficiently fetches chunks of data, cacheable per page.

POST with Idempotency Keys

POST /api/orders HTTP/1.1  
Content-Type: application/json  
Idempotency-Key: abc123

{"item": "book", "quantity": 1}

• Why? Prevents duplicate orders despite retries.

Conclusion

FAQs: POST vs GET Requests

1. Can GET requests include a body like POST?

2. Why does POST feel slower than GET?

3. How do I secure sensitive data in POST requests?

4. When should I use GET over POST for searches?

5. Can I make POST idempotent like GET?