Inbox

Inbox is an API Evangelist index of email and inbox-oriented API platforms that developers use to send, receive, parse, route, schedule, and verify email messages. The index focuses on transactional and conversational email providers exposing programmatic access to message lifecycle, deliverability, and inbox automation primitives.

Inbox publishes 2 APIs on the APIs.io network. Tagged areas include Email, Inbox, Messaging, Deliverability, and Transactional Email.

🌐 Visit website 📡 Source on GitHub

18.9/100 emerging ▬ flat Agent 3/100 human only Full breakdown ↓
scored 2026-07-28 · rubric v0.6

AccessFreemium

2 APIs

EmailInboxMessagingDeliverabilityTransactional Email

Kin Score

Kin Score How this is scored →
scored 2026-07-28 · rubric v0.6

Composite quality — 18.9/100 · emerging

Contract Quality 0.0 / 25

Developer Ergonomics 0.0 / 20

Commercial Clarity 9.5 / 20

Operational Transparency 4.1 / 13

Governance 0.0 / 12

Discoverability 5.9 / 10

Agent readiness — 3/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 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/inbox: 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 2

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

Mailgun Email API

Mailgun provides a programmable email API for sending, receiving, tracking, and validating email at scale. Endpoints cover messages, domains, suppressions, mailing lists, webhoo...

Nylas Email API

Nylas exposes a unified REST API for email, calendar, contacts, and scheduling across Google, Microsoft, iCloud, and IMAP providers. Developers can read, send, and thread messag...

Pricing Plans 1

Published pricing tiers and plan structures.

Inbox Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Inbox Rate Limits

5 limits

RATE LIMITS

FinOps 1

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

Access & Security 2

Authentication, authorization, and security posture

TrustCenter

TrustCenter

DomainSecurity

DomainSecurity

Company 1

The organization behind the API

Website

Website

Source (apis.yml)

aid: inbox
name: Inbox
description: Inbox is an API Evangelist index of email and inbox-oriented API platforms that developers use to send, receive,
  parse, route, schedule, and verify email messages. The index focuses on transactional and conversational email providers
  exposing programmatic access to message lifecycle, deliverability, and inbox automation primitives.
type: Index
accessModel:
  pricing: freemium
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Freemium
  confidence: medium
  source:
  - plans
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/inbox.png
tags:
- Email
- Inbox
- Messaging
- Deliverability
- Transactional Email
url: https://raw.githubusercontent.com/api-evangelist/inbox/refs/heads/main/apis.yml
created: '2024-12-25'
modified: '2026-04-28'
specificationVersion: '0.19'
apis:
- aid: inbox:mailgun-email-api
  name: Mailgun Email API
  description: Mailgun provides a programmable email API for sending, receiving, tracking, and validating email at scale.
    Endpoints cover messages, domains, suppressions, mailing lists, webhooks, inbound routes, event streams, and inbox placement
    testing for deliverability monitoring.
  humanURL: https://www.mailgun.com/
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  tags:
  - Email
  - Transactional Email
  - Deliverability
  - Inbound Parsing
  properties:
  - type: Documentation
    url: https://documentation.mailgun.com/docs/mailgun/api-reference/intro/
  - type: Reference
    url: https://documentation.mailgun.com/docs/mailgun/api-reference/openapi-final/tag/Introduction/
  - type: Pricing
    url: https://www.mailgun.com/pricing/
  - type: Signup
    url: https://signup.mailgun.com/new/signup
- aid: inbox:nylas-email-api
  name: Nylas Email API
  description: Nylas exposes a unified REST API for email, calendar, contacts, and scheduling across Google, Microsoft, iCloud,
    and IMAP providers. Developers can read, send, and thread messages, manage folders and labels, handle attachments, and
    subscribe to webhook notifications without integrating each provider individually.
  humanURL: https://www.nylas.com/products/email-api/
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  tags:
  - Email
  - Unified API
  - IMAP
  - Webhooks
  properties:
  - type: Documentation
    url: https://developer.nylas.com/docs/v3/email/
  - type: Reference
    url: https://developer.nylas.com/docs/api/v3/ecc/
  - type: Pricing
    url: https://www.nylas.com/pricing/
  - type: Signup
    url: https://dashboard-v3.nylas.com/register
common:
- type: TrustCenter
  url: security/inbox-trust-center.yml
- type: DomainSecurity
  url: security/inbox-domain-security.yml
- type: Website
  url: https://apievangelist.com/
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com