Paycor API facts that shape an MCP server
| Fact | Detail | Source |
|---|---|---|
| Official MCP server | None. The official MCP Registry returns no servers for "paycor" or "paychex", and Paycor’s developer portal content has no mention of MCP. | Official MCP Registry: search for paycor |
| Ownership | Paychex completed its acquisition of Paycor on April 14, 2025. | Paychex: acquisition of Paycor completed |
| API authentication | Every Public API call to https://apis.paycor.com needs both an APIM subscription key (the Ocp-Apim-Subscription-Key header or a subscription-key query parameter) and a valid OAuth access token. | Paycor Developer Portal: guides |
| Activation | Access is granted per client or legal entity through an activation flow that combines OAuth 2.0 with client admin authorization. In production a Paycor Perform company, payroll or HR admin must complete it, and each legal entity gets its own access token. | Paycor Developer Portal: guides |
| Tokens and scopes | Access tokens last 30 minutes, the offline_access scope is needed to get a refresh token, and the OAuth client secret expires every 365 days. Changing an app’s Data Access creates a new scope that clients must activate again. | Paycor Developer Portal: guides |
| Rate limits and paging | The portal states a default of up to 1,000 calls per minute across all Public APIs, counted per APIM subscription key, while an FAQ in the same portal says "currently 200 calls/minute". Page sizes are capped at 100 records. | Paycor Developer Portal: guides |
| Sandbox | Paycor provides separate Sandbox and Production environments with separate credentials. You request a sandbox through the portal’s support form, with a stated turnaround of 5 business days. | Paycor Developer Portal: guides |
| Events | Event notifications are POSTed to an unauthenticated endpoint you provide and signed with an HMAC using your event secret. Events must be subscribed before the client activates the app, or the client has to activate it again. | Paycor Developer Portal: guides |
| Partner access | Paycor says some data access scopes require Paycor’s approval, and partnership requests go through an approval process with the Paycor Alliances Team. | Paycor Developer Portal: guides |
| Sensitive data in hosted catalogs | Hosted Paycor catalogs reach sensitive records: among StackOne’s 38 Paycor actions are listing direct deposits, pay stubs and taxes for an employee, and updating personal data including SSN. | StackOne: Paycor MCP server |
Every way to connect Paycor to AI
| Option | Type | Fits when | Limits |
|---|---|---|---|
| StackOne Paycor MCP | Hosted | A fast pilot with 38 actions across employees, pay rates, time off and more, with managed authentication, field-level permission policies, prompt-injection filtering and audit logs. | Its catalog includes sensitive actions such as direct-deposit and pay-stub reads and SSN updates, so restrict fields and actions before you connect an assistant. Data passes through StackOne. |
| Knit Paycor MCP | Hosted | Read and write access through 26 prebuilt actions, such as creating or terminating employees and payroll statements, with Knit managing Paycor OAuth. Knit says it is a stateless passthrough that doesn’t store Paycor data. | Actions include terminations and payroll statements, so turn off what you don’t need. Pricing is by integrated accounts or API call volume, with a 30-day trial. |
| Merge Agent Handler | Hosted | Teams that already use Merge’s HRIS unified API and want the same connection for agents. | Merge lists its Paycor MCP server as beta, and its HRIS model includes bank account information, so scope that out for AI use. |
| Unified.to Paycor | Hosted | Real-time, pass-through reads of employees, payslips, time off and more, plus employee create and update; Unified.to says it doesn’t store end-customer data. | Its models include bank accounts and payslips, and a raw passthrough can call other Paycor endpoints, so lock both down. Usage-based pricing, with a 30-day trial. |
| Custom Paycor MCP server | Custom | Payroll-safe tools built for your questions (headcount, time off, payroll status) with field allowlists, per-legal-entity tokens held on the server, approvals for any write, and hosting in your own cloud. | Needs a Paycor developer application and admin activation, and you own token refresh, rate limiting and upkeep. |
Tools a Paycor MCP server should expose
Start with read-only tools and add write actions once the team trusts the answers. Every write action below runs with a confirmation or approval step.
| Tool | Access | Risk | Purpose | Guard |
|---|---|---|---|---|
get_headcount | Read | Low | Active employee count by legal entity, department or location. | Aggregates only; groups below a minimum size are suppressed so no one is identifiable. |
find_employee | Read | Medium | Look up an employee’s name, title, department, manager and status. | Allowlisted fields only; never returns SSN, birth date, home address or bank data. |
get_time_off_balances | Read | Medium | Time-off balances and upcoming approved leave for an employee or team. | Scoped to the caller’s own record, direct reports or HR population; no leave reasons returned. |
list_upcoming_new_hires | Read | Low | New hires and onboarding status for the next 30 days. | Names, roles and start dates only; no tax forms or identity documents. |
get_payroll_summary | Read | Medium | Totals for a pay period by legal entity (gross, taxes and net), for finance review. | Aggregates only, never per-employee pay stubs; payroll or finance role required. |
get_pay_rate | Read | High | Show one employee’s current pay rate to an authorized HR or payroll user. | HR or payroll role required; current rate only, no pay stub history; every call logged. |
submit_time_off_request | Write | Medium | Create a time-off request for the signed-in employee. | Employees can file only for themselves; the user confirms before submitting; manager approval stays in Paycor. |
import_payroll_hours | Write | High | Send approved hours and earnings for a pay period to Paycor. | Preview of totals per employee, then approval by a payroll admin; one idempotency key per pay period; blocked after the payroll cutoff. |
update_work_contact | Write | Medium | Update an employee’s work email or work phone. | Confirmation with before-and-after values; no changes to SSN, legal name, bank or tax fields through the agent. |
Connect it to Claude, ChatGPT or Copilot Studio
Claude
Add a hosted Paycor server or your own as a custom connector; for OAuth, enter the client ID and secret under Advanced settings. Calls come from Anthropic’s cloud, so a private server needs Anthropic’s IP ranges allowlisted. On Team and Enterprise plans only Owners add custom connectors, and each user then connects individually. Turn off write tools when using Research, which can call connector tools without asking each time.
ChatGPT
Use developer mode (Pro, Plus, Business, Enterprise and Education on the web; on Enterprise and Education a workspace admin grants access). ChatGPT treats tools without a readOnlyHint as writes and asks for confirmation. Keep Paycor tokens and subscription keys on the MCP server, never in the ChatGPT connection, and use Secure MCP Tunnel if the server must stay private.
Microsoft Copilot Studio
Add the server over Streamable HTTP with OAuth 2.0 so each person signs in with your company identity, and let the server map that identity to the employees they may see. Power Platform data policies govern MCP connections, so admins can control the Paycor server with the same policies they use for other connectors. Generative orchestration must be on.
Claude implementation · Copilot implementation · ChatGPT implementation
Permissions, identity and audit
- Paycor grants access per legal entity: a Paycor Perform company, payroll or HR admin activates your application, and each legal entity gets its own token. The MCP server keeps those tokens server-side and never passes them to the AI client.
- Paycor scopes come from the application’s Data Access choices. Request only what the tools need, since some scopes need Paycor’s approval and every change forces another activation.
- Paycor’s token represents the application’s access to a legal entity, not an individual employee, so the MCP server must map each signed-in person (from Entra ID or your identity provider) to what they may see: HR their population, managers their reports, employees themselves.
- Log every call with the user, the tool and the employee IDs touched, not the data returned, and review the logs with HR.
- Keep SSNs, bank accounts, tax IDs and full pay stubs out of every tool response; workflows that need them stay in Paycor’s own interface.
Hosting and network
- Hosted options run the MCP server and manage your Paycor credentials in the vendor’s cloud; check their data processing terms and where logs are kept.
- A custom server runs in your AWS or Azure account, with the Paycor client secret and refresh tokens in a secrets manager, calling https://apis.paycor.com over HTTPS.
- Claude and ChatGPT reach the server from their own clouds, so publish it behind authentication and an allowlist, or use ChatGPT’s Secure MCP Tunnel for a private deployment.
- Throttle to the lower rate Paycor states (200 calls per minute), use bulk endpoints where Paycor offers them, and cache reference data such as departments to save calls.
Cost and timeline
- Hosted servers are priced by each vendor: Knit prices by integrated accounts or API call volume with a 30-day trial, and Unified.to lists usage-based pricing with a 30-day trial.
- A focused read-only Paycor MCP server with payroll-safe tools typically takes two to four weeks including security and evaluation, plus Paycor’s own lead times: sandbox creation is stated as 5 business days, and partner access goes through Paycor’s approval.
- Write tools (time off, payroll hours) and multi-system work (Paycor plus an ERP or applicant tracking system) take longer and are scoped after a short discovery.
Paycor MCP questions
Does Paycor have an official MCP server?
No. As of September 2026 neither Paycor nor Paychex has published one: the official MCP Registry has no entries for either, and Paycor’s developer portal doesn’t mention MCP. Paychex has owned Paycor since April 2025.
Is there a free Paycor MCP server?
We found no maintained open-source Paycor MCP server on GitHub or in the MCP Registry on September 26, 2026. Hosted options offer trials (Knit and Unified.to list 30 days), and a custom server costs build time but no license fee.
Can an MCP server write to Paycor?
Yes. The Public API accepts some writes, such as time-off requests, employee updates and payroll hours, and hosted catalogs include actions like terminating an employee. We only expose writes with a preview, approval by the right Paycor role, and a log entry.
Does it work with Claude or Copilot?
Yes. Any of these servers can connect to Claude as a custom connector and to Copilot Studio as an existing MCP server over Streamable HTTP. The Paycor side doesn’t change: the server holds the Paycor tokens, and the AI client only sees tool results.
What do I need from Paycor for API access?
A Paycor developer portal account and application, an APIM subscription key, and an admin at the customer (a Paycor Perform company, payroll or HR admin) to complete activation. Partners apply through Paycor’s partner form and the Alliances Team’s approval, and some data scopes need Paycor’s approval.
How is payroll data protected?
By design, not by prompt. Tools return allowlisted fields only and never SSNs, bank details or full pay stubs, and aggregates suppress small groups. The server maps each user to the population they may see, and logs record who asked for what without storing the answers.
Hosted or custom?
Hosted servers are the quickest route to a pilot, but their catalogs include sensitive actions, so you must configure field and action limits. A custom server fits when HR needs payroll-safe tools, your own hosting and approvals mapped to your roles. AIONDATA is an independent provider, so we will say when a hosted option is enough.
