TriNet API
TriNet exposes roughly five REST APIs (employees, companies, payroll, money, time off) at developers.trinet.com, but access is partner-gated: sign-up approval, a separate API-key application, and technical review. Finch and Merge sell prebuilt TriNet connectors.
Frequently asked questions
TriNet scores A+ on the API Report Card. TriNet exposes roughly five REST APIs (employees, companies, payroll, money, time off) at developers.trinet.com, but access is partner-gated: sign-up approval, a separate API-key application, and technical review. Finch and Merge sell prebuilt TriNet connectors.
TriNet has a workable official integration path. Most engineering teams can build against it directly. Open API: self-serve, documented, with SDKs
TriNet (NYSE: TNET) is a Professional Employer Organization (PEO) and HR outsourcing provider that delivers full-service human capital management to small and medium-sized businesses.
Vertical: Enterprise HR / HCM / PEO. TriNet customers rely on the platform as the system of record for payroll, benefits, and HR compliance.
7/10. TriNet is one of the largest PEOs in the United States, serving roughly 23,000 SMB customers and reporting an average of ~340,744 Worksite Employees (WSEs) in Q1 2025, with ~$1.3B quarterly revenue.
TriNet holds extraordinarily sensitive operating data for its ~23,000 SMB customers and ~340,000+ worksite employees: SSNs and tax IDs, bank/ACH details for direct deposit, full compensation history, federal/state/local payroll tax filings, W-2 and 1099 records, health and retirement benefits enrollments, workers' compensation claims, I-9 and immigration records, and leave/medical accommodations data.
Founded in 1988; over 30 years in PEO. The core platform has been modernized iteratively, with the 2014 Ameriflex acquisition, 2016 IPO, 2022 Zenefits acquisition, and 2024 Cocoon (leave management) acquisition expanding capabilities.
Grades measure one thing: can a customer's engineering team get their own data out programmatically? We check six things (whether a real API exists, how access is gated, data coverage, auth quality, docs and developer experience, and stability) and roll them into a letter grade. Grades get re-verified, and they only move on evidence.