OnPay

OnPay is an Atlanta, Georgia based provider of full-service online payroll, HR, and employee benefits software for small and mid-size US businesses, founded in 2011 and funded by Carrick Capital Partners. The platform runs payroll and direct deposit, files federal, state, and local payroll taxes, and handles onboarding, PTO, org charts, health insurance, 401(k), and workers' compensation. For developers, OnPay publishes a partner-only REST API (v2) documented on a public ReadMe hub, covering employees, employee deductions, wages, leave, tax fields, bank accounts, terminations and rehires, company worksites, locations, departments and positions, pay schedules, and payroll reporting. Access is limited to approved partners, authorized with OAuth 2.0 authorization-code grants against app.onpay.com and role-scoped bearer tokens.

OnPay publishes 6 API contracts indexed on the APIs.io network, including Company API, Deductions API, Employees API, and 3 more. Tagged areas include Payroll, Human Resources, Employee Benefits, payroll-tax, and Small Business.

The OnPay catalog on APIs.io includes 1 Spectral governance ruleset.

OnPay’s developer surface includes documentation, API reference, getting-started guide, support, engineering blog, pricing, signup flow, and 23 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

55.5/100 strong ▬ flat Agent 27/100 agent aware Front door AI 1/6 silent saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessPaid

1 published contract 3 Agent Skills

Payroll Human Resources Employee Benefitspayroll-taxSmall Business Workforce Management Fintech Time and Attendanceretirement-401k

What this lets a business do 1

Business capabilities this provider's published APIs can perform, derived from its own contracts. Browse all capabilities →

Human Capital Management

BC-300

CompanyDeductionsEmployeesPay RunsReports

GET /employees GET /employees/{employee_id} GET /employees/{employee_id}/bank-accounts GET /employees/{employee_id}/wages

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 55.5/100 · strong

Contract Quality 8.4 / 19

Developer Ergonomics 8.8 / 15

Access Clarity 13.8 / 15

Operational Transparency 1.0 / 10

Contract Governance 1.6 / 9

Discoverability 5.5 / 8

Regulatory Posture 6.8 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 27/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 5 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 6 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 0 / 5

Distinct Operations 0 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Employment & Payroll regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented)
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document

9 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Contract Quality scores 44.9 — up to +13.8 composite points
Operational Transparency scores 10.5 — up to +11.6 composite points
Contract Governance scores 18.2 — up to +9.8 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/onpay/apis.yml: open an issue on github.com/api-evangelist/onpay to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Standards implemented 2

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

OpenAPI

measured — observed by APIs.io (published)

OAuth 2.0

measured — observed by APIs.io (declared)

APIs 6

Individual APIs this provider publishes, each with its own machine-readable definition.

OnPay Company API

The Company API from OnPay — 17 operation(s) for company.

OnPay Deductions API

The Deductions API from OnPay — 7 operation(s) for deductions.

OnPay Employees API

The Employees API from OnPay — 14 operation(s) for employees.

OnPay Pay Runs API

The Pay-runs API from OnPay — 2 operation(s) for pay-runs.

OnPay Reports API

The Reports API from OnPay — 2 operation(s) for reports.

OnPay User API

The User API from OnPay — 1 operation(s) for user.

Open Collections 6

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

OnPay Company API

OPEN COLLECTION

OnPay Deductions API

OPEN COLLECTION

OnPay Employees API

OPEN COLLECTION

OnPay Pay Runs API

OPEN COLLECTION

OnPay Reports API

OPEN COLLECTION

OnPay User API

OPEN COLLECTION

Agent Skills 3

Packaged agent skills for driving this provider's APIs from an AI assistant.

Change employee pay safely in OnPay

AGENT SKILL

Onboard an employee in OnPay

AGENT SKILL

Reconcile an OnPay pay run

AGENT SKILL

OnPay API pricing

Prices published by OnPay, read 2026-10-28 from onpay.com/payroll/software/costs-pricing/.

Plan	Price
Payroll Essentials (Base Plan)	$49 base + $6/worker per month Includes: Full-service payroll, tax filings, unlimited pay runs, multi-state payroll, benefits administration,
HR add-on	HR + $15 base and $2/worker per month Includes: PTO management, onboarding workflows, org charts, eSignature documents
Time Tracking add-on	Time Tracking + $15 base and $4/worker per month Includes: Time clocks, overtime rules, timesheets, PTO
Compliance Resources add-on	Compliance Resources + $10 base per month Includes: Compliance alerts, HR compliance library, job description builder
Live HR Support add-on	Live HR Support + $65 base per month Includes: On-demand concierge HR support, unlimited access
Benefits	Benefits Pay plan premiums only Includes: Group health, dental, vision; automated administration
Bundle: Payroll Essentials + Time Tracking + HR	$70 base + $10/worker Includes: Discounted from $79 base + $12/worker
Bundle: Payroll Essentials + HR + Compliance Resources + Live HR Support	$120 base + $7/worker Includes: Discounted from $139 base + $8/worker

All 9 plans, limits and sources →

Billed by: base + per worker · FinOps profile →

Pricing Plans 2

Published pricing tiers and plan structures.

Onpay Plans Pricing

9 plans

PLANS

Onpay Price Estimates

0 plans

PLANS

Service Levels 1

Uptime the provider promises or reports, as SLA4OAI. Read from its own pages; APIs.io runs no monitors.

OnPay

SLA

FinOps 1

Cost, billing, and metering signals for API financial operations.

Onpay Finops

FINOPS

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

OnPay API Rules

56 rules · 53 errors 1 warnings 2 info

SPECTRAL

OpenAPI Overlays 1

Overlays applied on top of this provider's contracts. Each card says who wrote it: a document the provider publishes, or one API Evangelist derived or generated.

Onpay Api Overlay

6 actions · update · onpay-api-openapi.json

DERIVED

Security Posture 3

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Onpay Authentication

apiKey/oauth2 · 2 schemes

SECURITY

Onpay Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Onpay Vulnerability Disclosure

Hackerone · contact published

SECURITY

Scopes 1

OAuth scopes governing access to this provider's APIs.

Onpay Scopes

6 scopes · authorizationCode

6 scopes

SCOPES

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Onpay Agentic Access

58 operations · 28 acting

AGENTIC

Resources

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

SignUp

SignUp

Login

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

X-MCPServerCandidate

AgenticAccess

LLMsTxt

AgentSkill

Design & Contract 5

Pagination, idempotency, versioning, errors, and events

Conventions

ErrorCatalog

Lifecycle

Conformance

DataModel

Access & Security 6

Authentication, authorization, and security posture

DomainSecurity

Security

Compliance

Authentication

OAuthScopes

VulnerabilityDisclosure

VulnerabilityDisclosure

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 4

Pricing, plans, and the legal terms of use

Plans

Pricing

TermsOfService

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 2

Properties that don't map to a standard resource type

CapabilityMap

CapabilityMap

Overlay

Overlay

Source (apis.yml)

aid: onpay
name: OnPay
description: OnPay is an Atlanta, Georgia based provider of full-service online payroll, HR, and employee benefits software
  for small and mid-size US businesses, founded in 2011 and funded by Carrick Capital Partners. The platform runs payroll
  and direct deposit, files federal, state, and local payroll taxes, and handles onboarding, PTO, org charts, health insurance,
  401(k), and workers' compensation. For developers, OnPay publishes a partner-only REST API (v2) documented on a public ReadMe
  hub, covering employees, employee deductions, wages, leave, tax fields, bank accounts, terminations and rehires, company
  worksites, locations, departments and positions, pay schedules, and payroll reporting. Access is limited to approved partners,
  authorized with OAuth 2.0 authorization-code grants against app.onpay.com and role-scoped bearer tokens.
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: paid
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Paid
  confidence: high
  source:
  - plans
  - authentication
  - scopes
  - security
  - sandbox
  generated: '2026-11-06'
  method: derived
image: https://onpay.com/wp-content/uploads/2017/08/d9fo84j1zi.jpg
url: https://raw.githubusercontent.com/api-evangelist/onpay/refs/heads/main/apis.yml
x-type: company
x-source: harvest:secondary-market
specificationVersion: '0.23'
created: '2026-08-04'
modified: '2026-08-04'
x-docs-platform: readme
x-docs-platform-confidence: high
x-docs-platform-checked: 2026-10-04
tags:
- Payroll
- Human Resources
- Employee Benefits
- payroll-tax
- Small Business
- Workforce Management
- Fintech
- Time and Attendance
- retirement-401k
tags_raw:
- payroll
- human-resources
- employee-benefits
- payroll-tax
- small-business
- workforce-management
- fintech
- hr-tech
- time-and-attendance
- retirement-401k
apis:
- aid: onpay:onpay-company-api
  name: OnPay Company API
  description: The Company API from OnPay — 17 operation(s) for company.
  humanURL: https://onpay.readme.io/reference/authorization
  baseURL: https://api.onpay.com/v2
  tags:
  - Company
  properties:
  - type: OpenAPI
    url: openapi/onpay-company-api-openapi.yml
  - type: Documentation
    url: https://onpay.readme.io/
  - type: APIReference
    url: https://onpay.readme.io/reference/authorization
  - type: Authentication
    url: authentication/onpay-authentication.yml
  - type: OAuthScopes
    url: scopes/onpay-scopes.yml
  - type: ErrorCatalog
    url: errors/onpay-problem-types.yml
  - type: Conventions
    url: conventions/onpay-conventions.yml
  - type: DataModel
    url: data-model/onpay-data-model.yml
  - type: LLMsTxt
    url: https://onpay.readme.io/llms.txt
- aid: onpay:onpay-deductions-api
  name: OnPay Deductions API
  description: The Deductions API from OnPay — 7 operation(s) for deductions.
  humanURL: https://onpay.readme.io/reference/authorization
  baseURL: https://api.onpay.com/v2
  tags:
  - Deductions
  properties:
  - type: OpenAPI
    url: openapi/onpay-deductions-api-openapi.yml
  - type: Documentation
    url: https://onpay.readme.io/
  - type: APIReference
    url: https://onpay.readme.io/reference/authorization
  - type: Authentication
    url: authentication/onpay-authentication.yml
  - type: OAuthScopes
    url: scopes/onpay-scopes.yml
  - type: ErrorCatalog
    url: errors/onpay-problem-types.yml
  - type: Conventions
    url: conventions/onpay-conventions.yml
  - type: DataModel
    url: data-model/onpay-data-model.yml
  - type: LLMsTxt
    url: https://onpay.readme.io/llms.txt
- aid: onpay:onpay-employees-api
  name: OnPay Employees API
  description: The Employees API from OnPay — 14 operation(s) for employees.
  humanURL: https://onpay.readme.io/reference/authorization
  baseURL: https://api.onpay.com/v2
  tags:
  - Employees
  properties:
  - type: OpenAPI
    url: openapi/onpay-employees-api-openapi.yml
  - type: Documentation
    url: https://onpay.readme.io/
  - type: APIReference
    url: https://onpay.readme.io/reference/authorization
  - type: Authentication
    url: authentication/onpay-authentication.yml
  - type: OAuthScopes
    url: scopes/onpay-scopes.yml
  - type: ErrorCatalog
    url: errors/onpay-problem-types.yml
  - type: Conventions
    url: conventions/onpay-conventions.yml
  - type: DataModel
    url: data-model/onpay-data-model.yml
  - type: LLMsTxt
    url: https://onpay.readme.io/llms.txt
- aid: onpay:onpay-pay-runs-api
  name: OnPay Pay Runs API
  description: The Pay-runs API from OnPay — 2 operation(s) for pay-runs.
  humanURL: https://onpay.readme.io/reference/authorization
  baseURL: https://api.onpay.com/v2
  tags:
  - Pay Runs
  tags_raw:
  - Pay-runs
  properties:
  - type: OpenAPI
    url: openapi/onpay-pay-runs-api-openapi.yml
  - type: Documentation
    url: https://onpay.readme.io/
  - type: APIReference
    url: https://onpay.readme.io/reference/authorization
  - type: Authentication
    url: authentication/onpay-authentication.yml
  - type: OAuthScopes
    url: scopes/onpay-scopes.yml
  - type: ErrorCatalog
    url: errors/onpay-problem-types.yml
  - type: Conventions
    url: conventions/onpay-conventions.yml
  - type: DataModel
    url: data-model/onpay-data-model.yml
  - type: LLMsTxt
    url: https://onpay.readme.io/llms.txt
- aid: onpay:onpay-reports-api
  name: OnPay Reports API
  description: The Reports API from OnPay — 2 operation(s) for reports.
  humanURL: https://onpay.readme.io/reference/authorization
  baseURL: https://api.onpay.com/v2
  tags:
  - Reports
  properties:
  - type: OpenAPI
    url: openapi/onpay-reports-api-openapi.yml
  - type: Documentation
    url: https://onpay.readme.io/
  - type: APIReference
    url: https://onpay.readme.io/reference/authorization
  - type: Authentication
    url: authentication/onpay-authentication.yml
  - type: OAuthScopes
    url: scopes/onpay-scopes.yml
  - type: ErrorCatalog
    url: errors/onpay-problem-types.yml
  - type: Conventions
    url: conventions/onpay-conventions.yml
  - type: DataModel
    url: data-model/onpay-data-model.yml
  - type: LLMsTxt
    url: https://onpay.readme.io/llms.txt
- aid: onpay:onpay-user-api
  name: OnPay User API
  description: The User API from OnPay — 1 operation(s) for user.
  humanURL: https://onpay.readme.io/reference/authorization
  baseURL: https://api.onpay.com/v2
  tags:
  - User
  properties:
  - type: OpenAPI
    url: openapi/onpay-user-api-openapi.yml
  - type: Documentation
    url: https://onpay.readme.io/
  - type: APIReference
    url: https://onpay.readme.io/reference/authorization
  - type: Authentication
    url: authentication/onpay-authentication.yml
  - type: OAuthScopes
    url: scopes/onpay-scopes.yml
  - type: ErrorCatalog
    url: errors/onpay-problem-types.yml
  - type: Conventions
    url: conventions/onpay-conventions.yml
  - type: DataModel
    url: data-model/onpay-data-model.yml
  - type: LLMsTxt
    url: https://onpay.readme.io/llms.txt
common:
- type: Plans
  url: plans/onpay-plans-pricing.yml
- type: CapabilityMap
  url: capabilities/onpay-capability-edges.yml
  name: OnPay Business Capability Map
- type: X-MCPServerCandidate
  url: mcp/onpay-mcp.yml
  note: 'Renamed from MCPServer 2026-09-03 (roadmap#247): the manifest self-describes as status: candidate — a tool list derived
    from the published API contracts, not an existing server. The scorer already read the manifest and reported mcp_server
    correctly; the MCPServer type was crediting the artifact-type surfaces with a server that does not exist.'
- type: Overlay
  url: overlays/onpay-api-overlay.yaml
- type: DomainSecurity
  url: security/onpay-domain-security.yml
- type: AgenticAccess
  url: agentic-access/onpay-agentic-access.yml
- type: Website
  url: https://onpay.com/
- type: DeveloperPortal
  url: https://onpay.readme.io/
- type: Documentation
  url: https://onpay.readme.io/
- type: APIReference
  url: https://onpay.readme.io/reference/authorization
- type: GettingStarted
  url: https://onpay.readme.io/docs/getting-started
- type: Support
  url: https://help.onpay.com/hc/en-us
- type: Blog
  url: https://onpay.com/insights/
- type: Pricing
  url: https://onpay.com/payroll/software/costs-pricing/
- type: SignUp
  url: https://onpay.com/get-started/
- type: Login
  url: https://app.onpay.com/app/login
- type: TermsOfService
  url: https://onpay.com/terms-of-service/
- type: PrivacyPolicy
  url: https://onpay.com/privacy/
- type: Security
  url: https://onpay.com/security/
- type: Compliance
  url: https://onpay.com/security/
- type: Integrations
  url: https://onpay.com/app-directory/
- type: LLMsTxt
  url: llms/onpay-llms.txt
- type: Authentication
  url: authentication/onpay-authentication.yml
- type: OAuthScopes
  url: scopes/onpay-scopes.yml
- type: Conventions
  url: conventions/onpay-conventions.yml
- type: ErrorCatalog
  url: errors/onpay-problem-types.yml
- type: Lifecycle
  url: lifecycle/onpay-lifecycle.yml
- type: Conformance
  url: conformance/onpay-conformance.yml
- type: DataModel
  url: data-model/onpay-data-model.yml
- type: VulnerabilityDisclosure
  url: security/onpay-vulnerability-disclosure.yml
- type: AgentSkill
  url: skills/_index.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-08-04'
  status: enriched
  artifacts_added: 20
  pass: local-v1

OnPay API — frequently asked questions

Does OnPay have an API?

Yes. APIs.io lists 6 APIs from OnPay, including OnPay Company API, OnPay Deductions API and OnPay Employees API, and 3 more.

Is there an OpenAPI specification for the OnPay API?

Yes. APIs.io indexes 6 OpenAPI specifications for OnPay, each linked for download from this page.

How do I authenticate with the OnPay API?

OnPay documents its authentication (apiKey/oauth2 · 2 schemes). The details are profiled on APIs.io as Onpay Authentication.

How much does the OnPay API cost?

OnPay publishes its prices; its Payroll Essentials (Base Plan) plan is $49 base + $6/worker per month as of 2026-10-28. APIs.io lists 9 pricing plans for OnPay, with each plan's price, limits and inclusions under Pricing on this page.

Is the OnPay API ready for AI agents?

OnPay has a Kin Score of 55.5 out of 100 (strong) and an Agent Readiness score of 27.4 (agent-aware), scored by API Evangelist on 2026-11-06.

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