Mesa

Mesa is a Boulder, Colorado fintech that provides embedded electronic-invoicing, payments, and invoice-financing (early-payment) infrastructure for B2B supplier networks. Suppliers get paid early via ACH while Mesa automates repayment once the buyer settles. Mesa ships as drop-in embedded UI — a JavaScript SDK (MesaClient) that renders Mesa's onboarding, dashboard, and instant-payout flows in an origin-pinned iframe inside a partner's web app — backed by a Partner REST API for user authentication and invoice retrieval. Auth is via API keys (clientId/clientSecret) exchanged for a short-lived JWT, with optional OIDC (Okta, Azure AD, Google). Backed by Matrix Partners; SOC 2.

Mesa publishes 2 API contracts indexed on the APIs.io network: Authentication API and Invoices API. Tagged areas include Company, Fintech, Payments, Invoice Financing, and Embedded Finance.

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

Mesa’s developer surface includes engineering blog, documentation, API reference, getting-started guide, authentication, signup flow, support, and 17 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

16.9/100 emerging ▬ flat Agent 21/100 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 →

1 published contract 2 Agent Skills

Company Fintech Payments Invoice Financing Embedded FinanceEarly PaymentACHSupplier PaymentsB2B

Kin Score

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

Composite quality — 16.9/100 · emerging

Contract Quality 2.6 / 19

Developer Ergonomics 3.1 / 15

Access Clarity 0.0 / 15

Operational Transparency 0.0 / 10

Contract Governance 2.9 / 9

Discoverability 5.1 / 8

Regulatory Posture 2.3 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 21/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 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 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Payments 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
Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author
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)
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes
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)

10 more unmet checks in the Agent Readiness table above.

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

Contract Quality scores 14.0 — up to +21.5 composite points
Access Clarity scores 0.0 — up to +20.0 composite points
Developer Ergonomics scores 20.8 — up to +15.8 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/mesa/apis.yml: open an issue on github.com/api-evangelist/mesa 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 3

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.

NACHA

tagged — the provider's own APIs.json carries the standard as a tag; implementation not verified

OpenAPI

measured — observed by APIs.io (published)

OpenID Connect

measured — observed by APIs.io (declared)

APIs 2

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

Mesa Authentication API

Exchange API keys for a session token.

Mesa Invoices API

Retrieve invoices for the authenticated user.

Open Collections 2

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

Mesa Partner Authentication API

OPEN COLLECTION

Mesa Partner Authentication Invoices API

OPEN COLLECTION

Agent Skills 2

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

Embed Mesa early-pay in a partner web app

AGENT SKILL

Authenticate a user and list their invoices

AGENT SKILL

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Mesa API Rules

61 rules · 59 errors 1 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.

Mesa Partner Api Overlay

3 actions · update · mesa-partner-api-openapi.yml

DERIVED

Security Posture 3

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

Mesa Authentication

apiKey/http/openIdConnect · 3 schemes

SECURITY

Mesa Domain Security

TLSv1.3 · DMARC

SECURITY

Mesa Trust Center

SOC 2

SECURITY

Resources

Get Started 3

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

SignUp

SignUp

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

X-MCPServerCandidate

X-MCPServerCandidate

AgentSkill

AgentSkill

Design & Contract 5

Pagination, idempotency, versioning, errors, and events

Conventions

Components

DataModel

Conformance

Lifecycle

Access & Security 5

Authentication, authorization, and security posture

Authentication

TrustCenter

Compliance

TrustCenter

DomainSecurity

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Blog

Blog

Website

Website

Other 1

Properties that don't map to a standard resource type

Overlay

Overlay

Source (apis.yml)

aid: mesa
name: Mesa
description: Mesa is a Boulder, Colorado fintech that provides embedded electronic-invoicing, payments, and invoice-financing
  (early-payment) infrastructure for B2B supplier networks. Suppliers get paid early via ACH while Mesa automates repayment
  once the buyer settles. Mesa ships as drop-in embedded UI — a JavaScript SDK (MesaClient) that renders Mesa's onboarding,
  dashboard, and instant-payout flows in an origin-pinned iframe inside a partner's web app — backed by a Partner REST API
  for user authentication and invoice retrieval. Auth is via API keys (clientId/clientSecret) exchanged for a short-lived
  JWT, with optional OIDC (Okta, Azure AD, Google). Backed by Matrix Partners; SOC 2.
url: https://raw.githubusercontent.com/api-evangelist/mesa/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- matrix-partners
x-tier: stub
x-tier-reason: portfolio-lead
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
  - security
  generated: '2026-11-06'
  method: derived
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-10-06'
image: https://www.joinmesa.com/favicon.ico
tags:
- Company
- Fintech
- Payments
- Invoice Financing
- Embedded Finance
- Early Payment
- ACH
- Supplier Payments
- B2B
apis:
- aid: mesa:mesa-authentication-api
  name: Mesa Authentication API
  description: Exchange API keys for a session token.
  humanURL: https://docs.joinmesa.com/partner-api/endpoints
  baseURL: https://api.joinmesa.com/v1
  tags:
  - Authentication
  properties:
  - type: OpenAPI
    url: openapi/mesa-authentication-api-openapi.yml
  - type: Documentation
    url: https://docs.joinmesa.com/partner-api
  - type: APIReference
    url: https://docs.joinmesa.com/partner-api/endpoints
- aid: mesa:mesa-invoices-api
  name: Mesa Invoices API
  description: Retrieve invoices for the authenticated user.
  humanURL: https://docs.joinmesa.com/partner-api/endpoints
  baseURL: https://api.joinmesa.com/v1
  tags:
  - Invoices
  properties:
  - type: OpenAPI
    url: openapi/mesa-invoices-api-openapi.yml
  - type: Documentation
    url: https://docs.joinmesa.com/partner-api
  - type: APIReference
    url: https://docs.joinmesa.com/partner-api/endpoints
common:
- url: https://www.joinmesa.com/blog/
  type: Blog
- type: Overlay
  url: overlays/mesa-partner-api-overlay.yaml
- type: Website
  url: https://www.joinmesa.com
- type: DeveloperPortal
  url: https://partners.joinmesa.com
- type: Documentation
  url: https://docs.joinmesa.com
- type: APIReference
  url: https://docs.joinmesa.com/partner-api/endpoints
- type: GettingStarted
  url: https://docs.joinmesa.com/embedded-ui/quickstart
- type: Authentication
  url: authentication/mesa-authentication.yml
- type: SignUp
  url: https://partners.joinmesa.com
- type: Support
  url: mailto:support@joinmesa.com
- type: TermsOfService
  url: https://www.joinmesa.com/terms
- type: PrivacyPolicy
  url: https://www.joinmesa.com/privacy
- type: TrustCenter
  url: https://trust.joinmesa.com
- type: Compliance
  url: https://trust.joinmesa.com
- type: Conventions
  url: conventions/mesa-conventions.yml
- type: Components
  url: components/mesa-components.yml
- type: DataModel
  url: data-model/mesa-data-model.yml
- type: Conformance
  url: conformance/mesa-conformance.yml
- type: Lifecycle
  url: lifecycle/mesa-lifecycle.yml
- type: LLMsTxt
  url: llms/mesa-llms.txt
- type: X-MCPServerCandidate
  url: mcp/mesa-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: TrustCenter
  url: security/mesa-trust-center.yml
- type: DomainSecurity
  url: security/mesa-domain-security.yml
x-enrichment:
  date: '2026-07-20'
  status: enriched
  artifacts_added: 15
  pass: local-v1

Mesa API — frequently asked questions

Does Mesa have an API?

Yes. APIs.io lists 2 APIs from Mesa, including Mesa Authentication API and Mesa Invoices API.

Is there an OpenAPI specification for the Mesa API?

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

How do I authenticate with the Mesa API?

Mesa uses bearer-token authentication (apiKey/http/openIdConnect · 3 schemes). The details are profiled on APIs.io as Mesa Authentication.

Is the Mesa API ready for AI agents?

Mesa has a Kin Score of 16.9 out of 100 (emerging) and an Agent Readiness score of 20.9 (agent-aware), scored by API Evangelist on 2026-11-06.

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