MailPace website screenshot

MailPace

MailPace is a fast, privacy-focused transactional email API for developers. It delivers application email - password resets, receipts, notifications - over a simple HTTPS REST API and SMTP, with DKIM-verified sending domains, Ed25519-signed webhooks, and EU-based hosting.

MailPace publishes 3 APIs on the APIs.io network: API Tokens API, Domains API, and Send API. Tagged areas include Email, Transactional Email, Messaging, SMTP, and Privacy.

MailPace’s developer surface includes authentication, documentation, and 8 more developer resources.

🌐 Visit website 📡 Source on GitHub
34.4/100 thin ▬ flat Agent 38/100 agent ready Full breakdown ↓
scored 2026-08-05 · rubric v0.9.1
AccessFreeSelf serve⚡ Free to try
4 APIs
EmailTransactional EmailMessagingSMTPPrivacy

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-08-05 · rubric v0.9.1
Composite quality — 34.4/100 · thin
Contract Quality 15.6 / 25
Developer Ergonomics 3.9 / 20
Commercial Clarity 5.8 / 20
Operational Transparency 4.8 / 13
Governance 0.0 / 12
Discoverability 7.4 / 10
Agent readiness — 38/100 · agent ready
Machine-Readable Contract 18 / 18
Agentic Access Contract 10 / 10
MCP Server 0 / 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
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/mailpace: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 4

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

MailPace Webhooks API

Delivers outbound, Ed25519-signed event callbacks (email.queued, email.delivered, email.deferred, email.bounced, email.spam) to your endpoints. Configured per domain in the Mail...

MailPace API Tokens API

Manage per-domain API tokens.

MailPace Domains API

Manage sending domains and DKIM verification.

MailPace Send API

Send transactional email.

Open Collections 1

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

MailPace API

OPEN COLLECTION

Pricing Plans 1

Published pricing tiers and plan structures.

Mailpace Plans Pricing

2 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Mailpace Rate Limits

3 limits

RATE LIMITS

FinOps 1

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

Mailpace Finops

FINOPS

Security Posture 2

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

Mailpace Authentication

apiKey · 2 schemes

SECURITY

Mailpace Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Agentic Access 1

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

Mailpace Agentic Access

11 operations · 7 acting · 1 human-in-the-loop

11 operations · 7 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

GitHubOrganization
GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity
DomainSecurity
 Authentication
Authentication

Operate 1

Status, limits, changes, and where to get help

RateLimits
RateLimits

Commercial 2

Pricing, plans, and the legal terms of use

Plans
Plans
 FinOps
FinOps

Company 2

The organization behind the API

LinkedIn
LinkedIn
 Website
Website

Source (apis.yml)

apis.yml Raw ↑ 
aid: mailpace
url: https://raw.githubusercontent.com/api-evangelist/mailpace/refs/heads/main/apis.yml
name: MailPace
kind: company
description: MailPace is a fast, privacy-focused transactional email API for developers. It delivers application email - password
  resets, receipts, notifications - over a simple HTTPS REST API and SMTP, with DKIM-verified sending domains, Ed25519-signed
  webhooks, and EU-based hosting.
accessModel:
  pricing: free
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  label: Free · Self-serve signup
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/mailpace.png
tags:
- Email
- Transactional Email
- Messaging
- SMTP
- Privacy
created: '2026-06-20'
modified: '2026-06-20'
specificationVersion: '0.19'
apis:
- aid: mailpace:mailpace-webhooks-api
  name: MailPace Webhooks API
  tags:
  - Webhooks
  - Events
  - Ed25519
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  humanURL: https://docs.mailpace.com/guide/webhooks/
  baseURL: https://app.mailpace.com/api/v1
  properties:
  - url: https://docs.mailpace.com/guide/webhooks/
    type: Documentation
  - url: review.yml
    type: Review
  description: Delivers outbound, Ed25519-signed event callbacks (email.queued, email.delivered, email.deferred, email.bounced,
    email.spam) to your endpoints. Configured per domain in the MailPace dashboard; the public verification key is exposed
    on the domain object.
- aid: mailpace:mailpace-api-tokens-api
  name: MailPace API Tokens API
  description: Manage per-domain API tokens.
  humanURL: https://docs.mailpace.com/reference/send/
  baseURL: https://app.mailpace.com/api/v1
  tags:
  - API Tokens
  properties:
  - type: OpenAPI
    url: openapi/mailpace-api-tokens-api-openapi.yml
  - type: Documentation
    url: https://docs.mailpace.com/reference/send/
  - type: APIReference
    url: https://docs.mailpace.com/reference/overview/
  - type: Documentation
    url: https://docs.mailpace.com/reference/domains/
- aid: mailpace:mailpace-domains-api
  name: MailPace Domains API
  description: Manage sending domains and DKIM verification.
  humanURL: https://docs.mailpace.com/reference/send/
  baseURL: https://app.mailpace.com/api/v1
  tags:
  - Domains
  properties:
  - type: OpenAPI
    url: openapi/mailpace-domains-api-openapi.yml
  - type: Documentation
    url: https://docs.mailpace.com/reference/send/
  - type: APIReference
    url: https://docs.mailpace.com/reference/overview/
  - type: Documentation
    url: https://docs.mailpace.com/reference/domains/
- aid: mailpace:mailpace-send-api
  name: MailPace Send API
  description: Send transactional email.
  humanURL: https://docs.mailpace.com/reference/send/
  baseURL: https://app.mailpace.com/api/v1
  tags:
  - Send
  properties:
  - type: OpenAPI
    url: openapi/mailpace-send-api-openapi.yml
  - type: Documentation
    url: https://docs.mailpace.com/reference/send/
  - type: APIReference
    url: https://docs.mailpace.com/reference/overview/
  - type: Documentation
    url: https://docs.mailpace.com/reference/domains/
common:
- type: AgenticAccess
  url: agentic-access/mailpace-agentic-access.yml
- type: DomainSecurity
  url: security/mailpace-domain-security.yml
- type: Authentication
  url: authentication/mailpace-authentication.yml
- type: GitHubOrganization
  url: https://github.com/mailpace
- type: LinkedIn
  url: https://www.linkedin.com/company/mailpace
- type: Website
  url: https://mailpace.com
- type: Documentation
  url: https://docs.mailpace.com
- type: Plans
  url: plans/mailpace-plans-pricing.yml
- type: RateLimits
  url: rate-limits/mailpace-rate-limits.yml
- type: FinOps
  url: finops/mailpace-finops.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com