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 26 more developer resources.

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51.7/100 developing Agent 56/100 agent ready Full breakdown ↓
scored 2026-10-23 · rubric v0.25.0 · Show this score on your site →

1 published contract

ERP Accounting Integration Software-as-a-Service

Kin Score

Kin Score How this is scored →
scored 2026-10-23 · rubric v0.25.0

Composite quality — 51.7/100 · developing

Contract Quality 11.2 / 21

Developer Ergonomics 8.8 / 17

Access Clarity 8.1 / 17

Operational Transparency 7.0 / 11

Contract Governance 2.2 / 10

Discoverability 4.9 / 9

Regulatory Posture 4.4 / 15

Agent readiness — 56/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 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 4 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 8 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 6 / 6

Protected Resource Metadata 5 / 5

Registration Without a Human 6 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 0 / 5

Distinct Operations 3 / 3

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 could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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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 github.com/api-evangelist/maesn: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

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.

Rate Limits 1

Documented rate limits and quota policies.

Maesn Rate Limits

9 limits

RATE LIMITS

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.

Maesn API Rules

12 rules · 8 errors 3 warnings 1 info

SPECTRAL

JSON Schema 6

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

BillResponseDto

32 properties

JSON SCHEMA

CreateBillRequestDto

29 properties

JSON SCHEMA

CreateVendorCreditRequestDto

29 properties

JSON SCHEMA

InvoiceResponseDto

30 properties

JSON SCHEMA

UpdateBillRequestDto

29 properties

JSON SCHEMA

VendorCreditResponseDto

32 properties

JSON SCHEMA

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 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 3

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Pricing

Pricing

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 3

Properties that don't map to a standard resource type

AgentCard

AgentCard

Hosts

Hosts

Vendors

Vendors

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.
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/
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-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-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-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-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-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-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-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
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

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