curl POST JSON on Linux

curl POST JSON is how operators and devs hit webhooks, internal APIs, and cloud control planes without opening Postman. Getting headers and quoting right avoids the classic “empty body / 415 Unsupported Media Type” errors.

Related: curl & wget,
jq,
API health script.

Minimal POST

Set Content-Type: application/json and pass a JSON string with -d.

bashPOST

curl -sS -X POST 'https://httpbin.org/post' \
  -H 'Content-Type: application/json' \
  -d '{"name":"server01","role":"web"}'

Authorization header

Bearer tokens and API keys belong in headers — never in shell history unquoted if avoidable.

bashtoken

curl -sS -H "Authorization: Bearer \$TOKEN" -H 'Content-Type: application/json' \
  -d '{"status":"ok"}' https://api.example.com/v1/heartbeat

Show HTTP status

Use -w to capture status code for scripts.

bashstatus

code=$(curl -sS -o /tmp/out.json -w '%{http_code}' https://api.example.com/health)
echo "HTTP \$code"
jq . /tmp/out.json

Pipe to jq

Validate structure before automation trusts the response.

WarningUse single quotes around JSON and escape inner quotes carefully in shell scripts.

Quick Reference

-H 'Content-Type: application/json'
Body: -d '{...}'
Scripts: capture %{{http_code}} with -w

curl POST JSON on Linux: Call REST APIs from the Terminal