When Would You Use HTTP GET vs POST?
The Short Answer
Use GET when you are retrieving data that doesn't change server state. Use POST when you are submitting data that creates or changes server-side state.
Key Differences
| Dimension | GET | POST |
|---|---|---|
| Safety | Safe — no side effects | Can cause side effects |
| Idempotency | Idempotent — same result every time | Not necessarily idempotent |
| Cacheability | Yes — GET responses are cached | No — responses are not cached by default |
| Visibility | Parameters are visible in the URL | Parameters are hidden in the body |
| Length limits | Limited to URL length (~2048 chars) | No practical limit |
| Bookmarking | Can be bookmarked | Cannot be bookmarked |
When to Use GET
- Loading a page or resource
- Search queries with parameters in the URL
- Filtering or paginating lists
- Any read-only operation
When to Use POST
- Submitting a form (creating a new user, placing an order)
- Uploading files
- Operations that change server state
- Sending sensitive data (POST body is encrypted in HTTPS, though URL parameters are visible in server logs even with HTTPS)
Follow-up Questions
Is GET always faster than POST?
For practical purposes, yes — GET requests with fewer parameters have shorter URLs and smaller headers. But the difference is negligible compared to network latency and server processing time.
Can GET requests have side effects?
They shouldn't. A GET request should never modify server state. If a GET request changes data (like incrementing a counter), it can cause serious problems when browsers pre-fetch links or when crawlers follow them.