ATS Assessment APIs in 2026: What Greenhouse, Workable, Ashby, Recruitee, TalentLyft and Cornerstone Require

Assessment APIs from Greenhouse, Workable, Ashby, Recruitee, TalentLyft, and Cornerstone are partner-only integrations that allow assessment, background-check, or reference-check vendors to offer tests within applicant tracking systems, receive recruiter-initiated orders, and return results to candidate records. Most require vendors to host endpoints that the ATS calls, while Ashby and Recruitee use bidirectional integrations; each platform also has distinct onboarding requirements, such as Greenhouse’s mutual-customer requirement, Workable’s 15-customer threshold for its native tier, Ashby’s legal review and live demo, and Cornerstone’s one-vendor-per-portal restriction. Recruiter workflows and result visibility vary substantially, with Greenhouse and Cornerstone supporting sortable scores, Recruitee allowing only manual assessment sending, and TalentLyft primarily showing results in activity feeds. The comparison emphasizes that partnership approval, service availability, incompatible result schemas, and differing ordering models are often more difficult than the technical API implementation itself. Unified assessment API providers aim to consolidate these varied endpoint and data models into a common package, order, and result workflow, though they do not remove individual ATS partnership and commercial requirements.

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