Testmail

Testmail is an email testing API platform for developers and QA teams that provides programmable inboxes with unlimited email addresses via a namespace.tag routing scheme. It offers both a JSON REST API and a GraphQL API for instant, programmatic retrieval of test emails, supporting automated end-to-end email testing in development workflows and CI/CD pipelines. Key capabilities include wildcard tag searches, live queries, pagination, spam score testing via SpamAssassin, and attachment handling.

Testmail publishes 2 APIs on the APIs.io network: Inbox API and Graph QL API. Tagged areas include Email Testing, Developer Tools, API Testing, GraphQL, and REST API.

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

Testmail’s developer surface includes authentication, documentation, engineering blog, pricing, and 9 more developer resources.

🌐 Visit website 📡 Source on GitHub

42.2/100 developing ▬ flat Agent 31/100 agent ready Front door AI 1/6 silent saas Full breakdown ↓
scored 2026-10-04 · rubric v0.23.0

AccessFreemiumSelf serve⚡ Free to try

1 published contract

Email Testing Developer Tools API Testing GraphQL REST API CI/CD QA AutomationProgrammable Inboxes

Kin Score

Kin Score How this is scored →
scored 2026-10-04 · rubric v0.23.0

Composite quality — 42.2/100 · developing

Contract Quality 11.6 / 19

Developer Ergonomics 3.6 / 15

Access Clarity 7.0 / 15

Operational Transparency 4.1 / 10

Contract Governance 0.9 / 9

Discoverability 5.0 / 8

Regulatory Posture 2.5 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 31/100 · 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 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 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

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/.

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/testmail-app: 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 2

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

Testmail Inbox API

Retrieve test emails from programmable inboxes

Testmail Graph QL API

GraphQL inbox query endpoint

Open Collections 3

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

API Collection

OPEN COLLECTION

Testmail GraphQL API

OPEN COLLECTION

Testmail GraphQL Inbox API

OPEN COLLECTION

GraphQL 1

GraphQL schemas published by this provider.

Testmail.app GraphQL API

The Testmail.app GraphQL API provides a full-featured interface for querying test emails from programmable inboxes. Emails are routed to addresses in the format `{namespace}.{ta...

GRAPHQL

Pricing Plans 1

Published pricing tiers and plan structures.

Testmail App Plans Pricing

4 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Testmail App Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Testmail App Finops

FINOPS

Semantic Vocabularies 1

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

Testmail App Context

6 classes · 38 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Testmail API Rules

5 rules · 4 warnings 1 info

SPECTRAL

JSON Schema 3

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

Email

11 properties

JSON SCHEMA

FilterInput

4 properties

JSON SCHEMA

InboxResponse

6 properties

JSON SCHEMA

Examples 4

Example request and response payloads for these APIs.

Graphql Inbox Query

4 fields

EXAMPLE

Graphql Livequery

5 fields

EXAMPLE

Json Api Get Emails

4 fields

EXAMPLE

Json Api Spam Report

4 fields

EXAMPLE

Security Posture 2

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

Testmail App Authentication

apiKey/http · 2 schemes

SECURITY

Testmail App Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

Agentic Access 1

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

Testmail App Agentic Access

2 operations · 1 acting

AGENTIC

Resources

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrg

GitHubOrg

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 2

Status, limits, changes, and where to get help

StatusPage

StatusPage

RateLimits

RateLimits

Commercial 3

Pricing, plans, and the legal terms of use

Pricing

Pricing

Plans

Plans

FinOps

FinOps

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

Source (apis.yml)

aid: testmail-app
name: Testmail
description: Testmail is an email testing API platform for developers and QA teams that provides programmable inboxes with
  unlimited email addresses via a namespace.tag routing scheme. It offers both a JSON REST API and a GraphQL API for instant,
  programmatic retrieval of test emails, supporting automated end-to-end email testing in development workflows and CI/CD
  pipelines. Key capabilities include wildcard tag searches, live queries, pagination, spam score testing via SpamAssassin,
  and attachment handling.
type: Index
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: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  label: Freemium · Self-serve signup
  confidence: medium
  source:
  - plans
  - authentication
  - security
  generated: '2026-09-03'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/testmail-app.png
url: https://raw.githubusercontent.com/api-evangelist/testmail-app/refs/heads/main/apis.yml
created: '2026-06-13'
modified: '2026-06-13'
specificationVersion: '0.23'
tags:
- Email Testing
- Developer Tools
- API Testing
- GraphQL
- REST API
- CI/CD
- QA Automation
- Programmable Inboxes
apis:
- aid: testmail-app:testmail-app-inbox-api
  name: Testmail Inbox API
  description: Retrieve test emails from programmable inboxes
  humanURL: https://testmail.app/docs/
  baseURL: https://api.testmail.app/api/json
  tags:
  - Inbox
  properties:
  - type: OpenAPI
    url: openapi/testmail-app-inbox-api-openapi.yml
  - type: Documentation
    url: https://testmail.app/docs/
  - type: GraphQL
    url: graphql/testmail-app-graphql.md
- aid: testmail-app:testmail-app-graph-ql-api
  name: Testmail Graph QL API
  description: GraphQL inbox query endpoint
  humanURL: https://testmail.app/docs/
  baseURL: https://api.testmail.app/api/graphql
  tags:
  - GraphQL
  tags_raw:
  - Graph QL
  properties:
  - type: OpenAPI
    url: openapi/testmail-app-graph-ql-api-openapi.yml
  - type: Documentation
    url: https://testmail.app/docs/
  - type: GraphQLEndpoint
    url: https://api.testmail.app/api/graphql
common:
- type: AgenticAccess
  url: agentic-access/testmail-app-agentic-access.yml
- type: DomainSecurity
  url: security/testmail-app-domain-security.yml
- type: Authentication
  url: authentication/testmail-app-authentication.yml
- type: Website
  url: https://testmail.app
- type: Documentation
  url: https://testmail.app/docs/
- type: GitHubOrg
  url: https://github.com/testmail-app
- type: X
  url: https://x.com/testmailapp
- type: Blog
  url: https://testmail.app/blog/
- type: Pricing
  url: https://testmail.app/pricing/
- type: StatusPage
  url: https://status.testmail.app
- type: Plans
  url: plans/testmail-app-plans-pricing.yml
- type: RateLimits
  url: rate-limits/testmail-app-rate-limits.yml
- type: FinOps
  url: finops/testmail-app-finops.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

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