Onsi

Onsi is a global technology provider and UK/EU insurance intermediary that delivers flexible, shift-linked worker benefits — on-demand ("Embedded") pay, insurance cover, and a rewards marketplace — to employers and their frontline workers. Its Partner (BMO) API lets benefit-program partners manage members (invite, read, update, replace, and offboard individually, in batches, or via full-list CSV jobs), read tiers and earned-wage balances, run on-demand pay withdrawals through a two-step intent/complete flow, and reconcile pay cycles and deductions with payroll. Authentication is an x-api-key header; requests support idempotency (x-idempotency-key, 7-day retention) and skip/take offset pagination, with a consistent code/message error envelope.

Onsi publishes 2 API contracts indexed on the APIs.io network: Members API and Pay API. Tagged areas include Company, Benefits, Earned Wage Access, On-Demand Pay, and Payroll.

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

Onsi’s developer surface includes documentation, API reference, getting-started guide, support, engineering blog, changelog, authentication, and 20 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

43.5/100 developing ▬ flat Agent 35/100 agent ready Front door AI 1/6 silent Heartbeat 0/100 dormant saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

1 published contract 4 Agent Skills

Company Benefits Earned Wage Access On-Demand Pay Payroll Fintech Insurance Workforce Human Resources Health Employee Benefits

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

Memberspay

POST /v1/pay/run GET /v1/pay/cycles GET /v1/pay/cycles/{id} GET /v1/pay/cycles/{id}/deductions

Kin Score

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

Composite quality — 43.5/100 · developing

Contract Quality 8.7 / 19

Developer Ergonomics 9.9 / 15

Access Clarity 3.2 / 15

Operational Transparency 3.6 / 10

Contract Governance 1.6 / 9

Discoverability 5.5 / 8

Regulatory Posture 3.3 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 35/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 9 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 7 / 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 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 0 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Insurance 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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<a href="https://apis.io/providers/onsi/"><img src="https://apis.io/badge/onsi/card.svg" alt="Onsi on APIs.io — Kin Score by API Evangelist"></a>

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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
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document
Delegated User Identity +6 pts — a served discovery document listing authorization_code in grant_types_supported (served), else an oauth2 authorizationCode flow or openIdConnect declared in an OpenAPI (documented)
Typed Event Surface +6 pts — AsyncAPI document, OR webhooks/callbacks objects in the as-published OpenAPI, OR common[].type includes Webhooks
Documented Reversibility +6 pts — a reversal operation in the contract, graded up when a window is documented too

6 more unmet checks in the Agent Readiness table above.

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

Access Clarity scores 21.1 — up to +15.8 composite points
Contract Quality scores 46.6 — up to +13.4 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/onsi/apis.yml: open an issue on github.com/api-evangelist/onsi 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 1

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)

APIs 2

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

Onsi Members API

The members API from Onsi — 7 operation(s) for members.

Onsi Pay API

The pay API from Onsi — 9 operation(s) for pay.

Open Collections 2

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

BMO Partner members API

OPEN COLLECTION

BMO Partner members pay API

OPEN COLLECTION

Agent Skills 4

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

Run an on-demand pay withdrawal

AGENT SKILL

Process end-of-cycle pay deductions

AGENT SKILL

Manage benefit-program members

AGENT SKILL

Sync a full member list via CSV job

AGENT SKILL

Rate Limits 1

Documented rate limits and quota policies.

Onsi Rate Limits

1 limits

RATE LIMITS

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Onsi API Rules

53 rules · 47 errors 5 warnings 1 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.

Onsi Overlay

3 actions · documentation · onsi-openapi-original.json

DERIVED

Security Posture 2

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

Onsi Authentication

apiKey · 1 scheme

SECURITY

Onsi Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Agentic Access 1

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

Onsi Agentic Access

20 operations · 10 acting

AGENTIC

Resources

Get Started 3

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

Sandbox

Sandbox

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

X-MCPServerCandidate

X-MCPServerCandidate

AgentSkill

AgentSkill

AgenticAccess

AgenticAccess

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

Conventions

Idempotency

ErrorCatalog

Lifecycle

Conformance

DataModel

Access & Security 2

Authentication, authorization, and security posture

Authentication

Authentication

DomainSecurity

DomainSecurity

Operate 4

Status, limits, changes, and where to get help

Support

ChangeLog

ChangeLog

RateLimits

Commercial 2

Pricing, plans, and the legal terms of use

PrivacyPolicy

PrivacyPolicy

TermsOfService

TermsOfService

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: onsi
name: Onsi
description: Onsi is a global technology provider and UK/EU insurance intermediary that delivers flexible, shift-linked worker
  benefits — on-demand ("Embedded") pay, insurance cover, and a rewards marketplace — to employers and their frontline workers.
  Its Partner (BMO) API lets benefit-program partners manage members (invite, read, update, replace, and offboard individually,
  in batches, or via full-list CSV jobs), read tiers and earned-wage balances, run on-demand pay withdrawals through a two-step
  intent/complete flow, and reconcile pay cycles and deductions with payroll. Authentication is an x-api-key header; requests
  support idempotency (x-idempotency-key, 7-day retention) and skip/take offset pagination, with a consistent code/message
  error envelope.
url: https://raw.githubusercontent.com/api-evangelist/onsi/refs/heads/main/apis.yml
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: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  - rate-limits
  - security
  - sandbox
  generated: '2026-11-06'
  method: derived
image: https://framerusercontent.com/assets/Kgx16PhdTJfIAzqiv0XeASdgeZU.jpg
x-type: company
x-source: vc-portfolio
x-backed-by:
- prosus-ventures
x-tier: stub
x-tier-reason: portfolio-lead
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-20'
x-docs-platform: mintlify
x-docs-platform-confidence: medium
x-docs-platform-checked: 2026-10-04
x-docs-hosting: vercel
tags:
- Company
- Benefits
- Earned Wage Access
- On-Demand Pay
- Payroll
- Fintech
- Insurance
- Workforce
- Human Resources
- Health
- Employee Benefits
tags_raw:
- Company
- Benefits
- Earned Wage Access
- On-Demand Pay
- Payroll
- Fintech
- Insurance
- Workforce
- HR
- Health
- Employee Benefits
apis:
- aid: onsi:onsi-members-api
  name: Onsi Members API
  description: The members API from Onsi — 7 operation(s) for members.
  humanURL: https://docs.onsi.com
  baseURL: https://api.onsi.com
  tags:
  - Members
  tags_raw:
  - members
  properties:
  - type: OpenAPI
    url: openapi/onsi-members-api-openapi.yml
  - type: Documentation
    url: https://docs.onsi.com
  - type: APIReference
    url: https://docs.onsi.com/api-reference/introduction
- aid: onsi:onsi-pay-api
  name: Onsi Pay API
  description: The pay API from Onsi — 9 operation(s) for pay.
  humanURL: https://docs.onsi.com
  baseURL: https://api.onsi.com
  tags:
  - Pay
  tags_raw:
  - pay
  properties:
  - type: OpenAPI
    url: openapi/onsi-pay-api-openapi.yml
  - type: Documentation
    url: https://docs.onsi.com
  - type: APIReference
    url: https://docs.onsi.com/api-reference/introduction
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: CapabilityMap
  url: capabilities/onsi-capability-edges.yml
  name: Onsi Business Capability Map
- type: Overlay
  url: overlays/onsi-overlay.yaml
- type: Website
  url: https://onsi.com
- type: DeveloperPortal
  url: https://docs.onsi.com
- type: Documentation
  url: https://docs.onsi.com
- type: APIReference
  url: https://docs.onsi.com/api-reference/introduction
- type: GettingStarted
  url: https://docs.onsi.com/docs/member-management/get-started
- type: Support
  url: https://onsi.com/contact
- type: Blog
  url: https://onsi.com/blog
- type: PrivacyPolicy
  url: https://pages.onsi.com/onsi-global-privacy-policy
- type: TermsOfService
  url: https://pages.onsi.com/onsi-terms-of-use-uk-and-row
- type: ChangeLog
  url: https://docs.onsi.com/docs/changelog
- type: ChangeLog
  url: changelog/onsi-changelog.yml
- type: LLMsTxt
  url: llms/onsi-llms.txt
- type: Authentication
  url: authentication/onsi-authentication.yml
- type: Conventions
  url: conventions/onsi-conventions.yml
- type: Idempotency
  url: conventions/onsi-conventions.yml
- type: ErrorCatalog
  url: errors/onsi-error-codes.yml
- type: RateLimits
  url: rate-limits/onsi-rate-limits.yml
- type: Lifecycle
  url: lifecycle/onsi-lifecycle.yml
- type: Conformance
  url: conformance/onsi-conformance.yml
- type: DataModel
  url: data-model/onsi-data-model.yml
- type: Sandbox
  url: sandbox/onsi-sandbox.yml
- type: X-MCPServerCandidate
  url: mcp/onsi-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: AgentSkill
  url: skills/_index.yml
- type: DomainSecurity
  url: security/onsi-domain-security.yml
- type: AgenticAccess
  url: agentic-access/onsi-agentic-access.yml
x-enrichment:
  date: '2026-07-20'
  status: enriched
  artifacts_added: 20
  pass: local-v1

Onsi API — frequently asked questions

Does Onsi have an API?

Yes. APIs.io lists 2 APIs from Onsi, including Onsi Members API and Onsi Pay API.

Is there an OpenAPI specification for the Onsi API?

Yes. APIs.io indexes 2 OpenAPI specifications for Onsi, each linked for download from this page.

How do I authenticate with the Onsi API?

Onsi uses bearer-token authentication (apiKey · 1 scheme). The details are profiled on APIs.io as Onsi Authentication.

Is the Onsi API ready for AI agents?

Onsi has a Kin Score of 43.5 out of 100 (developing) and an Agent Readiness score of 35.2 (agent-ready), scored by API Evangelist on 2026-11-06.

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