Transform Rules Playground

Visualize how transform rules modify requests through Vercel's network. To learn more about transform rules, read the docs.

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Read the docs →

Configuration

{ "src": "/users/:userId/posts/:postId", "transforms": [ { "type": "request.headers", "op": "set", "target": { "key": "x-user-id" }, "args": "$userId" }, { "type": "request.headers", "op": "set", "target": { "key": "authorization" }, "args": "Bearer $BEARER_TOKEN" }, { "type": "request.headers", "op": "append", "target": { "key": "session-temp" }, "args": [ "another" ] }, { "type": "response.headers", "op": "set", "target": { "key": "x-post-id" }, "args": "$postId" } ] }
/users/john-doe/posts/123?debug=true&limit=10

Client

Browser

Proxy

Vercel Edge

Origin

Backend Server

Original Request Headers

host: example.com
user-agent: Mozilla/5.0
x-debug-mode: enabled
session-temp: abc123

Original Query Parameters

No query parameters

Transformed Request Headers

No header transformations

Transformed Query Parameters

No query transformations

Transformed Response Headers

No response header transformations

Original Response Headers

content-type: application/json
server: nginx/1.18.0
x-response-time: 45ms

Applied Transforms

Send request to preview applied transforms

Operations: set, append, deleteTypes: request.headers, request.query, response.headers
Available Environment Variables: $API_KEY, $BEARER_TOKEN, $NODE_ENV, $REGION