Re-read the authentication section
Authentication decides how every request starts. Find the token endpoint, the required grant, the scopes and the expiry behaviour. Write a small request that only asks for a token. If that request fails, the rest of the documentation cannot help you yet.
Read how the API expects the token to be sent. A header name, a prefix or a signed request can differ from what you expect. Check whether a refresh token is available and what happens when a refresh fails during a long job.
Sketch the object model
Draw the main objects and the links between them. Look for the candidate, the application, the vacancy, the interview, the recording and the review. Note which id connects them and which id is stable across systems.
A stable external id is the anchor of the integration. If the documentation only offers an internal id, ask whether an external reference can be stored. Without that anchor, a second sync can create a duplicate record.
Check pagination, filters and limits
Find the pagination style: a page number, a cursor or a link header. Read what happens on the last page and how to request the next set. Then look at the filters. A list endpoint that cannot filter by the vacancy or the updated time forces your integration to read more data than it needs.
Note the rate limits and the recommended retry behaviour. If the documentation gives no production value, ask support. Treat a missing limit as an unknown, not as unlimited.
Follow one example from start to finish
Take one example request and trace the full path: request, response, stored id, follow-up call. Compare the field names in the example with the field table. Documentation examples can show a simplified payload, and a required field in the table can be missing from the example.
Test the example in the sandbox exactly as written. Then change one field and see which error comes back. That tells you how the API reports a validation problem, which is hard to learn from a success example.
Read the webhook and event sections
Check which events exist, what the payload contains and how the signature works. Find the retry policy and the replay procedure. A webhook without a replay path leaves a gap when your service is unavailable.
Look for the event ordering rule. If events can arrive out of order, your integration needs a time or version field to decide which state wins. Write that rule down before you handle the first event.
Turn gaps into a test plan
Keep a list of questions as you read. Each unclear sentence becomes a test or a support question. Group the questions by workflow: invite, record, review, decide and delete. Ask them in one message with the exact section you read.
Build a small test plan with one case for success and one for a failure at each step. Include an expired token, a duplicate event and a rejected field. Run the plan in the sandbox and record the result next to the documentation version.
The documentation is a map, not the territory. When the map is unclear, the test plan tells you where the integration needs a decision. That habit keeps a custom build from turning into a chain of guesses.