har-derived-api-client

Record the site's network traffic to a HAR file with Playwright while performing the target interaction, then run the derivation script to filter XHR/fetch/JSON entries. It prints each endpoint's method, path template, query params, headers, and body so you can replay it with plain HTTP.

Use the CDP capture script, which attaches to the remote browser with Playwright's connect_over_cdp and assembles the HAR from request/response events. Playwright's record_har_path only works on locally launched contexts, so cloud backends like Browserbase, Browser-Use, and Firecrawl require the CDP approach.

Many sites reject default library User-Agents like python-requests. Copy the browser User-Agent from the derivation's replay hints into your client, and resend captured Cookie or Authorization headers if the endpoint is session-gated.

Yes, the CDP capture script connects to any reachable Chrome DevTools Protocol endpoint and builds the HAR from network events. It does not close the browser afterward, since the browser is owned by the remote backend.

It captures and replays traffic but does not bypass authentication, solve CAPTCHAs, or defeat bot detection. Server-rendered pages with no XHR produce no derivable endpoints, and captured credentials expire, requiring re-capture when requests start returning 401.