PRACTICAL API GUIDES
API discovery guides.
Understand the traffic.
Start with a request you need to understand. These guides cover finding endpoints, tracing data between calls, generating documentation and reviewing changes over time.
01 / INVESTIGATE A WORKFLOW
Find the calls.
Follow the data.
Use Chrome to inspect individual exchanges, then build a repeatable investigation of an undocumented API.
Find a website’s API calls in Chrome
Identify useful requests, inspect their inputs and troubleshoot missing Fetch/XHR traffic.
Read the guideReverse engineer an undocumented API
Follow a real workflow, discover its requests and turn the observed behavior into documentation.
Read the guideTrace dependencies between API calls
Follow an identifier from response to request and reproduce the sequence in Postman.
Read the guide02 / DOCUMENT WHAT YOU OBSERVE
Choose the format
that fits the traffic.
HTTP requests, GraphQL types and live messages describe different parts of an application. Learn what each export contains and where its evidence stops.
Generate OpenAPI from browser traffic
From observed requests to an OpenAPI 3.1 document you can inspect and export.
Read the guideReconstruct a GraphQL schema
Discover types and operations, including traffic that uses persisted queries.
Read the guideDocument the real-time conversation
Turn observed stream messages into AsyncAPI channels and message schemas.
Read the guide03 / REVIEW CHANGES
Compare the next capture.
A new response shape may signal an API change or a gap in the earlier capture. Learn how to tell the difference.
SCHEMA DRIFT
What changed
between two captures?
Build comparable baselines, try two downloadable OpenAPI examples and review the differences that could affect your integration.
Read the schema drift guideQUESTIONS & ANSWERS
Frequently asked questions
Which guide should I read to find an API behind a website?
Start with the Chrome endpoint-discovery guide for a focused request inspection. Continue with the API reverse engineering guide when you need to investigate several workflows and organize the resulting documentation.
Which guide explains values passed between API calls?
The request-chaining guide follows identifiers from responses into later requests. It covers manual investigation, apispy Flow and a worked Postman example.
Where can I learn to compare API behavior over time?
The schema drift guide explains how to collect comparable captures, compare OpenAPI exports and investigate false alarms caused by permissions, records or incomplete coverage. It includes two downloadable example documents.