Maesn

Maesn provides a unified REST API that connects to major ERP and accounting systems such as DATEV, Sage, and Exact Online. It offers normalized data, authentication, and webhook support, enabling developers to integrate multiple financial platforms through a single endpoint.

Maesn publishes 5 API contracts indexed on the APIs.io network, including Accounting API, Auth API, Tenants API, and 2 more. Tagged areas include ERP, Accounting, Integration, and Software-as-a-Service.

The Maesn catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

Maesn’s developer surface includes getting-started guide, documentation, changelog, authentication, API reference, pricing, engineering blog, and 31 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

52.8/100 developing ▲ 10.9 Agent 29/100 agent ready Heartbeat 98/100 alive Full breakdown ↓
scored 2026-11-13 · rubric v0.28.0 · Show this score on your site →

1 published contract 2 Agent Skills

ERP Accounting Integration Software-as-a-Service

Kin Score

Kin Score How this is scored →
scored 2026-11-13 · rubric v0.28.0

Composite quality — 52.8/100 · developing

Contract Quality 10.1 / 19

Developer Ergonomics 7.8 / 15

Access Clarity 8.3 / 15

Operational Transparency 5.6 / 10

Contract Governance 2.0 / 9

Discoverability 4.8 / 8

Regulatory Posture 4.4 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 29/100 · 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 0 / 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 Horizontal (data, software, accessibility, platform) 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 Ask about this →
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes Ask about this →
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0 Ask about this →
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document Ask about this →
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) Ask about this →
Typed Event Surface +6 pts — AsyncAPI document, OR webhooks/callbacks objects in the as-published OpenAPI, OR common[].type includes Webhooks Ask about this →

7 more unmet checks in the Agent Readiness table above.

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

Contract Quality scores 53.7 — up to +11.6 composite points Ask about this →
Developer Ergonomics scores 51.8 — up to +9.6 composite points Ask about this →
Contract Governance scores 22.0 — up to +9.4 composite points Ask about this →

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.

Not sure how this applies to your stack? Ask about any one item. Kin Lane reads every question, looks at your profile and your situation, and replies with what a fix would take — scoped to that one area, priced up front, yours whether you ship it or not. Ask a question →

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/maesn/apis.yml: open an issue on github.com/api-evangelist/maesn 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 5

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

Maesn Accounting API

The accounting API from Maesn — 91 operation(s) for accounting.

Maesn Auth API

The auth API from Maesn — 4 operation(s) for auth.

Maesn Tenants API

The tenants API from Maesn — 6 operation(s) for tenants.

Maesn User API

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

Maesn Webhook API

The webhook API from Maesn — 2 operation(s) for webhook.

Agent Skills 2

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

maesn-setup-tenant

AGENT SKILL

maesn-webhook-management

AGENT SKILL

Maesn API pricing

Rate limits

abacus: minute
abacus: hour
abacus: day

All 9 limits →

Rate Limits 1

Documented rate limits and quota policies.

Maesn Rate Limits

9 limits

RATE LIMITS

Terms of Service 1

What its API terms permit and prohibit, quoted from its own page.

Maesn

10 quoted statements, read from Maesn's own page on 2026-11-10.

TERMS

Privacy & Data 1

Its role, the data it processes, retention and transfers, quoted from its own privacy page.

Maesn

30 quoted statements, read from Maesn's own page on 2026-11-10.

PRIVACY

Compliance 1

Attestations the provider states (SOC 2, ISO 27001 and others), quoted from its own trust page. APIs.io verifies none of them.

Maesn

2 quoted statements, read from Maesn's own page on 2026-11-10.

COMPLIANCE

Eligibility 1

Who may sign up and where, quoted from its own terms.

Maesn

1 quoted statement, read from Maesn's own page on 2026-11-10.

ELIGIBILITY

Data License 1

How its data and outputs may be reused, quoted from its own terms.

Maesn

1 quoted statement, read from Maesn's own page on 2026-11-10.

LICENSE

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Maesn Context

120 classes · 265 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs. Counts are the severity each rule declares, not results of running them.

Maesn API Rules

45 rules · 38 error-severity 6 warn-severity 1 info-severity

SPECTRAL

OpenAPI Overlays 4

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.

Maesn Accounting Api Certification Overlay

36 actions · update · maesn-accounting-api-openapi.yml

DERIVED

Maesn Auth Api Certification Overlay

2 actions · update · maesn-auth-api-openapi.yml

DERIVED

Maesn Tenants Api Certification Overlay

1 action · update · maesn-tenants-api-openapi.yml

DERIVED

Maesn User Api Certification Overlay

1 action · update · maesn-user-api-openapi.yml

DERIVED

JSON Schema 18

Standalone JSON Schema definitions for this provider's data models.

BaseResponseDto

2 properties

JSON SCHEMA

BillResponseDto

32 properties

JSON SCHEMA

CallbackUrlRegistrationDto

2 properties

JSON SCHEMA

CompanyResponseDto

6 properties

JSON SCHEMA

CreateBillRequestDto

29 properties

JSON SCHEMA

CreateEndUserRequestDto

8 properties

JSON SCHEMA

CreateVendorCreditRequestDto

29 properties

JSON SCHEMA

CreateWebhookRequestDto

3 properties

JSON SCHEMA

EndUserResponseDto

4 properties

JSON SCHEMA

EnvironmentResponseDto

5 properties

JSON SCHEMA

InvoiceResponseDto

30 properties

JSON SCHEMA

PostAuthRequestDto

7 properties

JSON SCHEMA

SystemRegistrationDto

3 properties

JSON SCHEMA

UpdateBillRequestDto

29 properties

JSON SCHEMA

UserInfoDto

4 properties

JSON SCHEMA

VendorCreditResponseDto

32 properties

JSON SCHEMA

WebhookResponseDto

5 properties

JSON SCHEMA

WebhookResponseDtoWithSecret

6 properties

JSON SCHEMA

Scroll for all 18

Security Posture 3

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

Maesn Authentication

2 schemes

SECURITY

Maesn Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Maesn Trust Center

ISO 27001, GDPR

SECURITY

Agentic Access (API Evangelist recommendations) 1

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

Maesn Agentic Access

145 operations · 60 acting

AGENTIC

Resources

Get Started 1

Portal, sign-up, and the first successful call

GettingStarted

GettingStarted

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgentSkill

LLMsTxt

WellKnown

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Spectral

JSONLD

Vocabulary

DataModel

Idempotency

Conventions

Conformance

Scroll for all 7

Build 3

SDKs, sample code, and the tooling you integrate with

SDKs

SDKs

Packages

Packages

GitHubOrganization

GitHubOrganization

Access & Security 5

Authentication, authorization, and security posture

Compliance

Authentication

Security

TrustCenter

DomainSecurity

Operate 3

Status, limits, changes, and where to get help

RateLimits

RateLimits

ChangeLog

ChangeLog

ChangeLog

ChangeLog

Commercial 5

Pricing, plans, and the legal terms of use

TermsOfService

PrivacyPolicy

Pricing

UsageTerms

DataLicense

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 6

Properties that don't map to a standard resource type

AgentCard

Hosts

Vendors

DataProcessing

Attestations

Eligibility

Source (apis.yml)

aid: maesn
name: Maesn
description: Maesn provides a unified REST API that connects to major ERP and accounting systems such as DATEV, Sage, and
  Exact Online. It offers normalized data, authentication, and webhook support, enabling developers to integrate multiple
  financial platforms through a single endpoint.
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  - rate-limits
  - security
  generated: '2026-11-13'
  method: derived
image: https://www.maesn.com/images/brand/maesn-logo.svg
url: https://raw.githubusercontent.com/api-evangelist/maesn/refs/heads/main/apis.yml
x-type: company
x-source: harvest:g2-catalog
x-tier: profiled
x-tier-reason: enrichment pass 2026-10-20 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-10-20'
modified: '2026-10-20'
tags:
- ERP
- Accounting
- Integration
- Software-as-a-Service
tags_raw:
- ERP
- Accounting
- Integration
- API
- SaaS
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: GettingStarted
  url: https://docs.maesn.com/guides/quick-start
- type: Documentation
  url: https://docs.maesn.com/
- type: AgenticAccess
  url: agentic-access/maesn-agentic-access.yml
- type: RateLimits
  url: rate-limits/maesn-rate-limits.yml
- type: Spectral
  url: rules/maesn-rules.yml
- type: JSONLD
  url: json-ld/maesn-context.jsonld
- type: Vocabulary
  url: vocabulary/maesn-vocabulary.yml
- type: AgentSkill
  url: skills/_index.yml
- type: DataModel
  url: data-model/maesn-data-model.yml
- type: ChangeLog
  url: changelog/maesn-changelog.yml
- type: Idempotency
  url: conventions/maesn-conventions.yml
- type: Conventions
  url: conventions/maesn-conventions.yml
- type: Compliance
  url: https://www.maesn.com/security/
- type: Authentication
  url: authentication/maesn-authentication.yml
- type: Conformance
  url: conformance/maesn-conformance.yml
- type: LLMsTxt
  url: llms/maesn-llms.txt
- type: AgentCard
  url: a2a/maesn-a2a.yml
- type: WellKnown
  url: well-known/maesn-well-known.yml
- type: Hosts
  url: hosts/maesn-hosts.yml
- type: Vendors
  url: vendors/maesn-vendors.yml
- type: SDKs
  url: packages/maesn-packages.yml
- type: Packages
  url: packages/maesn-packages.yml
- type: TermsOfService
  url: https://www.maesn.com/terms-of-service/
- type: Security
  url: https://www.maesn.com/security/
- type: PrivacyPolicy
  url: https://www.maesn.com/privacy-policy/
- type: GitHubOrganization
  url: https://github.com/maesndev
- type: ChangeLog
  url: https://docs.maesn.com/changelog
- type: APIReference
  url: https://docs.maesn.com/llms.txt
- type: TrustCenter
  url: security/maesn-trust-center.yml
- type: DomainSecurity
  url: security/maesn-domain-security.yml
- type: Website
  url: https://www.maesn.com/
- type: Pricing
  url: https://www.maesn.com/pricing/
- type: Blog
  url: https://www.maesn.com/blog/
- type: UsageTerms
  url: terms/maesn-terms-of-service.yml
- type: DataProcessing
  url: privacy/maesn-privacy-policy.yml
- type: Attestations
  url: compliance/maesn-compliance.yml
- type: Eligibility
  url: eligibility/maesn-eligibility.yml
- type: DataLicense
  url: data-license/maesn-data-license.yml
apis:
- aid: maesn:maesn-accounting-api
  name: Maesn Accounting API
  description: The accounting API from Maesn — 91 operation(s) for accounting.
  humanURL: https://docs.maesn.com/introduction
  baseURL: https://api.maesn.dev
  tags:
  - Accounting
  tags_raw:
  - accounting
  properties:
  - type: OpenAPI
    url: openapi/maesn-accounting-api-openapi.yml
  - type: JSONSchema
    url: json-schema/maesn-vendor-credit-response-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-bill-response-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-invoice-response-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-create-vendor-credit-request-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-update-bill-request-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-create-bill-request-dto-schema.json
- aid: maesn:maesn-auth-api
  name: Maesn Auth API
  description: The auth API from Maesn — 4 operation(s) for auth.
  humanURL: https://docs.maesn.com/introduction
  baseURL: https://api.maesn.dev
  tags:
  - Authentication
  tags_raw:
  - auth
  properties:
  - type: OpenAPI
    url: openapi/maesn-auth-api-openapi.yml
  - type: JSONSchema
    url: json-schema/maesn-post-auth-request-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-create-end-user-request-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-company-response-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-environment-response-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-base-response-dto-schema.json
- aid: maesn:maesn-tenants-api
  name: Maesn Tenants API
  description: The tenants API from Maesn — 6 operation(s) for tenants.
  humanURL: https://docs.maesn.com/introduction
  baseURL: https://api.maesn.dev
  tags:
  - Tenants
  tags_raw:
  - tenants
  properties:
  - type: OpenAPI
    url: openapi/maesn-tenants-api-openapi.yml
  - type: JSONSchema
    url: json-schema/maesn-end-user-response-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-system-registration-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-callback-url-registration-dto-schema.json
- aid: maesn:maesn-user-api
  name: Maesn User API
  description: The user API from Maesn — 1 operation(s) for user.
  humanURL: https://docs.maesn.com/introduction
  baseURL: https://api.maesn.dev
  tags:
  - User
  tags_raw:
  - user
  properties:
  - type: OpenAPI
    url: openapi/maesn-user-api-openapi.yml
  - type: JSONSchema
    url: json-schema/maesn-user-info-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-base-response-dto-schema.json
- aid: maesn:maesn-webhook-api
  name: Maesn Webhook API
  description: The webhook API from Maesn — 2 operation(s) for webhook.
  humanURL: https://docs.maesn.com/introduction
  baseURL: https://api.maesn.dev
  tags:
  - Webhook
  tags_raw:
  - webhook
  properties:
  - type: OpenAPI
    url: openapi/maesn-webhook-api-openapi.yml
  - type: JSONSchema
    url: json-schema/maesn-webhook-response-dto-with-secret-schema.json
  - type: JSONSchema
    url: json-schema/maesn-create-webhook-request-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-webhook-response-dto-schema.json
  - type: JSONSchema
    url: json-schema/maesn-base-response-dto-schema.json
x-enrichment:
  date: '2026-10-20'
  status: enriched
  artifacts_added: 40
  pass: modular-v1
  engine: identity=local,contract=local,surfaces=local,docs=local,regulatory=local

Maesn API — frequently asked questions

Does Maesn have an API?

Yes. APIs.io lists 5 APIs from Maesn, including Maesn Accounting API, Maesn Auth API and Maesn Tenants API, and 2 more.

Is there an OpenAPI specification for the Maesn API?

Yes. APIs.io indexes 5 OpenAPI specifications for Maesn, each linked for download from this page.

How do I authenticate with the Maesn API?

Maesn uses bearer-token authentication (2 schemes). The details are profiled on APIs.io as Maesn Authentication.

Is the Maesn API ready for AI agents?

Maesn has a Kin Score of 52.8 out of 100 (developing) and an Agent Readiness score of 29.1 (agent-ready), scored by API Evangelist on 2026-11-13.

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