Gusto
Payroll, benefits and HRUS payroll, benefits and HR for small businesses. Its MCP server brings live payroll and people data into AI tools, with per-category permissions and confirmation before any write.
MCPAPI/CLIBulk import
Ops
O
OnPay
Payroll and HR Ops API/CLIBulk import
Independent review. IonBin has no partnership with OnPay and was not paid for this page. Our evaluation is our own, based on public documentation and our research. Product names are trademarks of their owners and are used for identification only. How disclosure works.
Payroll, HR and benefits for US small businesses, with tax filings and year-end forms included. Its API is limited to approved partners; no official MCP server found.
Not advice
IonBin provides general information and software comparisons, not tax, legal, accounting or financial advice. Tax and legal rules vary by situation and jurisdiction; consult a qualified professional (CPA, enrolled agent or attorney) before acting.
AI tools can make mistakes. Verify every figure against the original documents and official IRS or state guidance before filing or signing.
Redact Social Security numbers, account numbers and EINs before uploading documents to any AI assistant, and check its data-retention settings. Upload originals only to the filing or signing software.
Best for
- Small businesses running US payroll
Not for
- Global teams
Top use cases
- Run US payroll with federal, state and local tax filings included source ↗
In depth
Pricing
OnPay Payroll is $49/month plus $6 per worker and includes W-2s, 1099s, year-end filings, unlimited pay runs and multi-state payroll. HR starts at $15/month plus $2 per worker and Time Tracking at $15 plus $4 per worker, with bundle discounts. Benefits integration is free; you pay plan premiums. Checked 2026-10-17. source ↗
How to use it with AI
How OnPay connects to each AI platform: native connector or MCP, API through code the agent writes, browser control, or file upload.
| Platform | MCP / connector | API (agent-written code) | Browser | Upload / export |
|---|---|---|---|---|
| Claude (incl. Claude Code) | No documented route | Confirmed Claude (incl. Claude Code) can run code; OnPay publishes an API. OnPay API ↗Claude (incl. Claude Code) docs ↗ | Confirmed Claude Code with the Claude in Chrome extension (Chrome, Edge and other Chromium browsers) Claude (incl. Claude Code) browser docs ↗ | Confirmed Export from OnPay, then works on the files in your project; chat accepts attachments Claude (incl. Claude Code) docs ↗ |
| OpenAI Codex | No documented route | Confirmed OpenAI Codex can run code; OnPay publishes an API. OnPay API ↗OpenAI Codex docs ↗ | Confirmed Only in the ChatGPT desktop app; not in the Codex CLI or IDE extension OpenAI Codex browser docs ↗ | Confirmed Export from OnPay, then works on local repositories OpenAI Codex docs ↗ |
| Google Antigravity | No documented route | Confirmed Google Antigravity can run code; OnPay publishes an API. OnPay API ↗Google Antigravity docs ↗ | Confirmed Browser subagent via /browser, documented as an Antigravity App feature; the IDE has separate browser docs Google Antigravity browser docs ↗ | Confirmed Export from OnPay, then works on local projects and worktrees Google Antigravity docs ↗ |
Confirmed means both the tool's and the platform's official docs describe that route (links in the cell); IonBin has not tested every pairing. Not documented means it may work, but no official docs describe that route end to end. Checked Oct 17, 2026.
Agent compatibility
API/CLIBulk import
| Level | Status | Detail / source |
|---|---|---|
| Native connector / MCP | No | No official MCP server found (2026-10-17) |
| API / CLI | Yes | Official docs ↗ |
| Browser-only | No | Web app; also reachable programmatically |
| Bulk upload / import | Yes | Free data migration during setup (https://onpay.com/pricing) |
Recorded Oct 17, 2026. Setup and plan limits vary; check the vendor's docs. How levels are assigned.
Works well with
Connects to agent platforms
No confirmed MCP server yet.
Via its API, through automation hubs: Gumloop, Make, n8n, Zapier.
Workflows using this tool
- Set up payroll with a checklist Reviewed
Review
No long-form review yet. Verdict is based on research, not hands-on testing.
Alternatives
Justworks
PEO and payrollA professional employer organization (PEO) and payroll provider for US teams, with an employer-of-record option for hiring abroad. Integrations use a Partner API for approved partners; no official MCP server found.
API/CLIBulk import
Ops