Export candidates in bulk via Greenhouse Harvest API

Steps

1. Authenticate using HTTP Basic Auth with your Harvest API key as the username and an empty string as the password; all requests go to https://harvest.greenhouse.io/v1 (v1/v2) or use the v3 base at harvestdocs.greenhouse.io — note v1 and v2 are deprecated after August 31 2026, so target v3 for new integrations
2. Send GET /v1/candidates (or the v3 equivalent) with per_page set up to 500 to maximize page size and reduce round trips
3. Inspect the Link response header for a rel="next" URL; follow it on each iteration until no next link is returned — Harvest v3 uses cursor-based pagination ordered by id descending
4. Monitor X-RateLimit-Remaining on each response; if it approaches zero or you receive HTTP 429, pause for the number of seconds specified in the Retry-After header before resuming
5. Optionally filter the initial request with query parameters such as updated_after (ISO 8601 timestamp) to fetch only candidates modified since your last sync
6. Write each page of results to your destination store before requesting the next page to avoid re-fetching on failure