List and cross-link Candidates and Job Openings records via Zoho Recruit's REST API v2

Steps

1. Register a client in the Zoho API Console and run the OAuth 2.0 flow against https://accounts.zoho.com/oauth/v2/auth, requesting Recruit-specific scopes such as ZohoRecruit.modules.candidates.ALL and ZohoRecruit.modules.jobopenings.ALL (or ZohoRecruit.modules.ALL for full access).
2. Note the API host is recruit.zoho.com/recruit/v2/ — a separate host and OAuth scope namespace (ZohoRecruit.*) from Zoho CRM's zohoapis.com hosts and ZohoCRM.* scopes; CRM tokens are not valid here.
3. GET https://recruit.zoho.com/recruit/v2/settings/modules (or /settings/modules/{module_api_name}) to confirm which recruit-specific modules — Candidates, Job_Openings, Interviews, Assessments, etc. — are available and flagged api_supported: true for your account.
4. GET https://recruit.zoho.com/recruit/v2/Candidates or https://recruit.zoho.com/recruit/v2/Job_Openings to list records, sending header 'Authorization: Zoho-oauthtoken {access_token}'.
5. Use each module's exact api_name as returned by the modules endpoint (e.g. 'Candidates', 'Job_Openings') — default module api_names cannot be renamed, only custom modules can.
6. Use the Associate Candidate / Get Associated Records endpoints to fetch a Candidate's linked Job Openings or a Job Opening's linked Candidates.