OnPay API
OnPay runs a real API but publishes no self-serve docs; direct access is a negotiated partnership. Most developers reach OnPay through Finch's unified API, which exposes Organization, Payroll, and Deductions over an OAuth connect flow.
Frequently asked questions
OnPay scores C on the API Report Card. OnPay runs a real API but publishes no self-serve docs; direct access is a negotiated partnership. Most developers reach OnPay through Finch's unified API, which exposes Organization, Payroll, and Deductions over an OAuth connect flow.
OnPay has an official API, but teams routinely hit its limits: gated access, partial coverage, or paid tiers. Most end up supplementing it with exports or an unofficial API layer like Supergood.
OnPay is a cloud-based, full-service payroll, HR, and benefits platform for U.S. small and mid-sized businesses. Headquartered in Atlanta, OnPay traces its roots to a family payroll service founded in the 1980s and relaunched as a SaaS product in 2007.
Vertical: Enterprise / HR / ERP (SMB Payroll & HR). Running scheduled and unscheduled payroll for W-2 employees and 1099 contractors in all 50 states.
Moderate within the SMB payroll segment. OnPay serves tens of thousands of U.S. small businesses and is a consistent fixture in "best small business payroll" rankings from outlets like NerdWallet, Forbes Advisor, USA Today, PCMag, and CNBC.
Employee PII (legal name, SSN, DOB, address, phone, email). Bank routing and account numbers for direct deposit. Wages, salaries, hourly rates, tipped wages, piece-rate pay, bonuses, commissions, reimbursements.
OnPay's parent business has roots in a 1980s family payroll bureau, but the modern SaaS product has been in market since roughly 2007 and has been continuously modernized (cloud-native, mobile-friendly, self-service onboarding).
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.