How do I send JSON with curl?

Use -H 'Content-Type: application/json' and --data-raw '{...}'. Example: curl -X POST -H 'Content-Type: application/json' --data-raw '{"name":"Alice"}' 'https://api.example.com/users'.

How do I add headers to a curl request?

Add one or more -H flags. Example: curl -H 'Accept: application/json' -H 'X-API-Key: YOUR_KEY' 'https://api.example.com'.

How do I authenticate with curl (Bearer token or Basic Auth)?

For Bearer tokens, add -H 'Authorization: Bearer TOKEN'. For Basic Auth, use -u 'username:password'.

cURL Command Builder

Build a ready-to-run curl command for any HTTP request — headers, query params, JSON body, auth, and common flags. Everything runs locally in your browser.

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Request

Method

URL

Include any existing query string (e.g. ?page=2) or add params below.

Query parameters

Headers

Authentication

Bearer token

Adds Authorization: Bearer …

Basic auth (user:pass)

Adds -u 'user:pass'

Body

Type

Body

File upload (multipart)

Field name

File path

Uses -F 'field=@/path/to/file' (for local CLI use).

Common flags

Follow redirects (-L) Include response headers (-i) Verbose (-v) Silent (-s) Fail on HTTP errors (--fail-with-body) Insecure TLS (-k)

Output

Save response to file

Timeout (seconds)

Uses --max-time (0 = omit).

Presets

Presets only fill the form in your browser — nothing is sent anywhere.

Generated curl command

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cURL Command Builder

Related Resources

HTTP Request Tester

cURL Commands Cheat Sheet

REST API Design Guide

Frequently Asked Questions