checkmails

checkmails (checkmails.eu) is a European real-time SMTP email verification service operated by ZENITH SARL (Tourcoing, France; SIREN 104 935 366). It checks addresses live against recipient mail servers (RCPT TO, no email sent), including iCloud/@me/@mac via a dedicated EU proxy, from uploaded Excel/CSV lists, a REST API, an MCP integration for AI assistants, and a free Odoo module. Data is hosted by Scaleway in Paris, payments go through Mollie, files are auto-deleted, and the service is positioned as a GDPR-native alternative to US verifiers.

checkmails publishes 4 API contracts indexed on the APIs.io network, including Bulk API, Jobs API, Verify API, and 1 more. Tagged areas include Company, Email Verification, SMTP, GDPR, and Data Quality.

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

checkmails’ developer surface includes authentication, documentation, pricing, signup flow, legal docs, and 28 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

49.9/100 developing Agent 28/100 agent aware Full breakdown ↓
scored 2026-11-13 · rubric v0.28.0 · Show this score on your site →

AccessFreemiumSelf serve⚡ Free to try

1 published contract 1 MCP Servers

Company Email Verification SMTP GDPR Data Quality European Union MCP Odoo

Kin Score

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

Composite quality — 49.9/100 · developing

Contract Quality 10.9 / 19

Developer Ergonomics 4.3 / 15

Access Clarity 11.2 / 15

Operational Transparency 3.7 / 10

Contract Governance 2.0 / 9

Discoverability 4.9 / 8

Regulatory Posture 3.7 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 28/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 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):

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) Ask about this →
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0 Ask about this →
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link 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 →

8 more unmet checks in the Agent Readiness table above.

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

Developer Ergonomics scores 28.6 — up to +14.3 composite points Ask about this →
Contract Quality scores 58.1 — up to +10.5 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.

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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 the provider profile at artifacts.apis.io/checkmails-eu/apis.yml: open an issue on github.com/api-evangelist/checkmails-eu 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.

Model Context Protocol (MCP)

measured — observed by APIs.io (documented)

OpenAPI

measured — observed by APIs.io (published)

APIs 4

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

checkmails MCP Server

Remote MCP server for email verification from AI assistants, advertised in the checkmails OpenAPI info.description at https://checkmails.eu/api/mcp (connect guide https://checkm...

checkmails Bulk API

The Bulk API from checkmails — 1 operation(s) for bulk.

checkmails Jobs API

The Jobs API from checkmails — 1 operation(s) for jobs.

checkmails Verify API

The Verify API from checkmails — 1 operation(s) for verify.

MCP Servers 1

Model Context Protocol servers that expose these APIs to AI agents.

checkmails MCP server

Official remote MCP server published by checkmails.eu for SMTP email verification from AI agents (Claude, Cursor, ChatGPT, any MCP client). JSON-RPC 2.0, MCP protocol revision 2...

MCP SERVER

checkmails API pricing

Prices published by checkmails.

Plan	Price
Free	0 €
Pack Découverte	5 €
Starter	19 €
Pro	49 €
Enterprise	99 €
Custom	On request

Plan details, limits and sources →

Rate limits

verify: 60 requests per minute per API key
bulk: 10 requests per minute per API key
jobs: 60 requests per minute per API key

All 4 limits →

Pricing Plans 1

Published pricing tiers and plan structures.

checkmails Plans Pricing

6 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

checkmails Rate Limits

4 limits

RATE LIMITS

Terms of Service 1

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

checkmails

7 quoted statements, read from checkmails's own page on 2026-11-09.

TERMS

Privacy & Data 1

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

checkmails

41 quoted statements, read from checkmails's own page on 2026-11-09.

PRIVACY

Eligibility 1

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

checkmails

4 quoted statements, read from checkmails's own page on 2026-11-09.

ELIGIBILITY

Data License 1

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

checkmails

2 quoted statements, read from checkmails's own page on 2026-11-09.

LICENSE

Semantic Vocabularies 1

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

Checkmails Eu Context

2 classes · 12 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.

checkmails API Rules

46 rules · 44 error-severity 1 warn-severity 1 info-severity

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.

checkmails Openapi Overlay

4 actions · documentation · checkmails-eu-openapi.yml

GENERATED

JSON Schema 1

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

Result

10 properties

JSON SCHEMA

Security Posture 2

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

checkmails Authentication

http · 1 scheme

SECURITY

checkmails Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Agentic Access (API Evangelist recommendations) 1

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

checkmails Agentic Access

3 operations · 2 acting

AGENTIC

Resources

Get Started 1

Portal, sign-up, and the first successful call

SignUp

SignUp

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

MCPServer

MCPServer

AgenticAccess

AgenticAccess

LLMsTxt

LLMsTxt

Design & Contract 8

Pagination, idempotency, versioning, errors, and events

Spectral

JSONLD

Vocabulary

DataModel

Conventions

Lifecycle

ErrorCatalog

Conformance

Scroll for all 8

Build 3

SDKs, sample code, and the tooling you integrate with

IntegrationEdges

IntegrationEdges

SDKs

SDKs

Packages

Packages

Access & Security 3

Authentication, authorization, and security posture

Authentication

Authentication

DomainSecurity

DomainSecurity

Security

Security

Operate 1

Status, limits, changes, and where to get help

RateLimits

RateLimits

Commercial 7

Pricing, plans, and the legal terms of use

Plans

Pricing

TermsOfService

PrivacyPolicy

Legal

UsageTerms

DataLicense

Scroll for all 7

Company 1

The organization behind the API

Website

Website

Other 5

Properties that don't map to a standard resource type

Overlay

Hosts

SubProcessors

DataProcessing

Eligibility

Source (apis.yml)

aid: checkmails-eu
name: checkmails
description: checkmails (checkmails.eu) is a European real-time SMTP email verification service operated by ZENITH SARL (Tourcoing,
  France; SIREN 104 935 366). It checks addresses live against recipient mail servers (RCPT TO, no email sent), including
  iCloud/@me/@mac via a dedicated EU proxy, from uploaded Excel/CSV lists, a REST API, an MCP integration for AI assistants,
  and a free Odoo module. Data is hosted by Scaleway in Paris, payments go through Mollie, files are auto-deleted, and the
  service is positioned as a GDPR-native alternative to US verifiers.
url: https://artifacts.apis.io/checkmails-eu/apis.yml
x-type: company
x-source: harvest:mcp-registry
x-tier: profiled
x-tier-reason: enrichment pass 2026-11-03 (modular-v1; was harvest)
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  gated: none
  gated_source:
  - onboarding
  label: Freemium · Self-serve signup
  confidence: high
  probe_state: covered
  source:
  - plans
  - authentication
  - rate-limits
  - security
  generated: '2026-11-13'
  method: derived
specificationVersion: '0.20'
created: '2026-11-03'
modified: '2026-11-03'
tags:
- Company
- Email Verification
- SMTP
- GDPR
- Data Quality
- European Union
- MCP
- Odoo
tags_raw:
- Company
- Email Verification
- Email Validation
- SMTP
- GDPR
- Data Quality
- European Union
- MCP
- Odoo
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
image: https://checkmails.eu/static/og-card.png
common:
- type: MCPServer
  url: mcp/checkmails-eu-mcp.yml
- type: AgenticAccess
  url: agentic-access/checkmails-eu-agentic-access.yml
- type: RateLimits
  url: rate-limits/checkmails-eu-rate-limits.yml
- type: Plans
  url: plans/checkmails-eu-plans-pricing.yml
- type: Spectral
  url: rules/checkmails-eu-rules.yml
- type: JSONLD
  url: json-ld/checkmails-eu-context.jsonld
- type: Vocabulary
  url: vocabulary/checkmails-eu-vocabulary.yml
- type: DataModel
  url: data-model/checkmails-eu-data-model.yml
- type: Conventions
  url: conventions/checkmails-eu-conventions.yml
- type: Lifecycle
  url: lifecycle/checkmails-eu-lifecycle.yml
- type: ErrorCatalog
  url: errors/checkmails-eu-problem-types.yml
- type: Conformance
  url: conformance/checkmails-eu-conformance.yml
- type: Overlay
  url: overlays/checkmails-eu-openapi-overlay.yaml
- type: LLMsTxt
  url: llms/checkmails-eu-llms.txt
- type: Hosts
  url: hosts/checkmails-eu-hosts.yml
- type: IntegrationEdges
  url: integrations/checkmails-eu-integration-edges.yml
- type: SDKs
  url: packages/checkmails-eu-packages.yml
- type: Packages
  url: packages/checkmails-eu-packages.yml
- type: Authentication
  url: authentication/checkmails-eu-authentication.yml
- type: DomainSecurity
  url: security/checkmails-eu-domain-security.yml
- type: Website
  url: https://checkmails.eu/
- type: Documentation
  url: https://checkmails.eu/docs
- type: Pricing
  url: https://checkmails.eu/#pricing
- type: SignUp
  url: https://checkmails.eu/register
- type: TermsOfService
  url: https://checkmails.eu/cgv
- type: PrivacyPolicy
  url: https://checkmails.eu/privacy
- type: Security
  url: https://checkmails.eu/security
- type: Legal
  url: https://checkmails.eu/legal
- type: SubProcessors
  url: https://checkmails.eu/subprocessors
- type: Integrations
  url: https://checkmails.eu/odoo
- type: UsageTerms
  url: terms/checkmails-eu-terms-of-service.yml
- type: DataProcessing
  url: privacy/checkmails-eu-privacy-policy.yml
- type: Eligibility
  url: eligibility/checkmails-eu-eligibility.yml
- type: DataLicense
  url: data-license/checkmails-eu-data-license.yml
apis:
- aid: checkmails-eu:checkmails-mcp-server
  name: checkmails MCP Server
  description: Remote MCP server for email verification from AI assistants, advertised in the checkmails OpenAPI info.description
    at https://checkmails.eu/api/mcp (connect guide https://checkmails.eu/mcp); anonymous requests return 401 (Bearer token
    required).
  humanURL: https://checkmails.eu/mcp
  baseURL: https://checkmails.eu/api/mcp
  tags:
  - MCP
  - Email Verification
  properties:
  - type: Documentation
    url: https://checkmails.eu/mcp
- aid: checkmails-eu:checkmails-eu-bulk-api
  name: checkmails Bulk API
  description: The Bulk API from checkmails — 1 operation(s) for bulk.
  humanURL: https://checkmails.eu/docs
  baseURL: https://checkmails.eu
  tags:
  - Bulk
  properties:
  - type: OpenAPI
    url: openapi/checkmails-eu-bulk-api-openapi.yml
  - type: Documentation
    url: https://checkmails.eu/docs
- aid: checkmails-eu:checkmails-eu-jobs-api
  name: checkmails Jobs API
  description: The Jobs API from checkmails — 1 operation(s) for jobs.
  humanURL: https://checkmails.eu/docs
  baseURL: https://checkmails.eu
  tags:
  - Job
  tags_raw:
  - Jobs
  properties:
  - type: OpenAPI
    url: openapi/checkmails-eu-jobs-api-openapi.yml
  - type: Documentation
    url: https://checkmails.eu/docs
  - type: JSONSchema
    url: json-schema/checkmails-eu-result-schema.json
- aid: checkmails-eu:checkmails-eu-verify-api
  name: checkmails Verify API
  description: The Verify API from checkmails — 1 operation(s) for verify.
  humanURL: https://checkmails.eu/docs
  baseURL: https://checkmails.eu
  tags:
  - Verify
  properties:
  - type: OpenAPI
    url: openapi/checkmails-eu-verify-api-openapi.yml
  - type: Documentation
    url: https://checkmails.eu/docs
  - type: JSONSchema
    url: json-schema/checkmails-eu-result-schema.json
x-coverage:
  state: covered
  reason: identity-verified
  detail: Name, legal entity and pointers read from checkmails.eu homepage (title "checkmails — European email verification")
    and /legal (éditeur ZENITH SARL). /register and /login not fetched by this pass (auth-endpoint rule); /register liveness
    taken from the preflight dossier site_links (200).
  evidence:
  - url: https://checkmails.eu/
    status: 200
  - url: https://checkmails.eu/docs
    status: 200
  - url: https://checkmails.eu/legal
    status: 200
  - url: https://checkmails.eu/cgv
    status: 200
  - url: https://checkmails.eu/privacy
    status: 200
  - url: https://checkmails.eu/security
    status: 200
  - url: https://checkmails.eu/subprocessors
    status: 200
  - url: https://checkmails.eu/odoo
    status: 200
  - url: https://checkmails.eu/openapi.json
    status: 200
  - url: https://checkmails.eu/static/og-card.png
    status: 200
x-enrichment:
  date: '2026-11-03'
  status: enriched
  artifacts_added: 28
  pass: modular-v1
  engine: identity=anthropic,contract=anthropic,surfaces=anthropic,docs=anthropic,regulatory=anthropic

checkmails API — frequently asked questions

Does checkmails have an API?

Yes. APIs.io lists 4 APIs from checkmails, including checkmails MCP Server, checkmails Bulk API and checkmails Jobs API, and 1 more.

Is there an OpenAPI specification for the checkmails API?

Yes. APIs.io indexes 3 OpenAPI specifications for checkmails, each linked for download from this page.

How do I authenticate with the checkmails API?

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

How much does the checkmails API cost?

checkmails publishes its prices; its Free plan is 0 € as of 2026-11-03. APIs.io lists 6 pricing plans for checkmails, with each plan's price, limits and inclusions under Pricing on this page.

Does checkmails have an MCP server?

Yes. APIs.io lists 1 MCP server for checkmails: Official remote MCP server published by checkmails.eu for SMTP email verification from AI agents (Claude, Cursor, ChatGPT, any MCP client). JSON-RPC 2.0, MCP protocol revision 2025-06-18.

Is the checkmails API ready for AI agents?

checkmails has a Kin Score of 49.9 out of 100 (developing) and an Agent Readiness score of 28.0 (agent-aware), scored by API Evangelist on 2026-11-13.

Work with this as data

Every provider here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

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