Resend

Resend is a developer-first email API platform that simplifies sending and managing transactional and marketing emails. It provides a clean REST API with bearer token authentication, supporting email sending, domain management, API key management, audience and contact management, and broadcast campaigns. Resend offers SDKs for Node.js, Python, Go, Ruby, PHP, Java, .NET, Rust, Elixir, and more, along with a React Email library and official MCP server.

Resend publishes 6 APIs on the APIs.io network, including Audiences API, Broadcasts API, Domains API, and 3 more. Tagged areas include Email, Developer Tools, Transactional Email, and Marketing Email.

The Resend catalog on APIs.io includes 1 event-driven AsyncAPI specification, 1 JSON-LD context, and 3 Spectral governance rulesets.

Resend’s developer surface includes changelog, engineering blog, code examples, pricing, signup flow, CLI, and 23 more developer resources.

🌐 Visit website 📡 Source on GitHub

54.1/100 developing ▬ flat Agent 50/100 agent ready Front door AI 1/6 silent saas Full breakdown ↓
scored 2026-09-25 · rubric v0.23.0

AccessFreemium

1 APIs 1 MCP Servers 5 Agent Skills

Email Developer Tools Transactional Email Marketing Email

Kin Score

Kin Score How this is scored →
scored 2026-09-25 · rubric v0.23.0

Composite quality — 54.1/100 · developing

Contract Quality 12.5 / 19

Developer Ergonomics 6.5 / 15

Access Clarity 7.1 / 15

Operational Transparency 6.2 / 10

Contract Governance 2.5 / 9

Discoverability 5.0 / 8

Regulatory Posture 4.1 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 50/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 6 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 6 / 6

Agent Skills 5 / 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 6 / 6

Protected Resource Metadata 5 / 5

Registration Without a Human 6 / 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/resend: 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 6

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

Resend Audiences API

Create and manage Audiences through the Resend API.

Resend Broadcasts API

The Broadcasts API from Resend — 2 operation(s) for broadcasts.

Resend Domains API

Create and manage domains through the Resend API.

Resend Emails API

Start sending emails through the Resend API.

Resend Send API

The Send API from Resend — 1 operation(s) for send.

Resend APIS API

The Apis API from Resend — 2 operation(s) for apis.

Postman Collections 13

Ready-to-run Postman collections for exercising this provider's APIs.

Resend Apis API

POSTMAN

Resend Audience API

POSTMAN

Resend Audiences API

POSTMAN

Resend Batch API

POSTMAN

Resend Broadcasts API

POSTMAN

Resend Cancel API

POSTMAN

Resend Contacts API

POSTMAN

Resend Domains API

POSTMAN

Resend Email API

POSTMAN

Resend Emails API

POSTMAN

Resend Keys API

POSTMAN

Resend Send API

POSTMAN

Resend Verify API

POSTMAN

Scroll for all 13

Open Collections 14

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

API Collection

OPEN COLLECTION

Resend Apis API

OPEN COLLECTION

Resend Audience API

OPEN COLLECTION

Resend Audiences API

OPEN COLLECTION

Resend Batch API

OPEN COLLECTION

Resend Broadcasts API

OPEN COLLECTION

Resend Cancel API

OPEN COLLECTION

Resend Contacts API

OPEN COLLECTION

Resend Domains API

OPEN COLLECTION

Resend Email API

OPEN COLLECTION

Resend Emails API

OPEN COLLECTION

Resend Keys API

OPEN COLLECTION

Resend Send API

OPEN COLLECTION

Resend Verify API

OPEN COLLECTION

Scroll for all 14

MCP Servers 1

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

MCP Server

MCP SERVER

Agent Skills 5

Packaged agent skills for driving this provider's APIs from an AI assistant.

agent-email-inbox

AGENT SKILL

email-best-practices

AGENT SKILL

react-email

AGENT SKILL

resend-cli

AGENT SKILL

resend

AGENT SKILL

Pricing Plans 1

Published pricing tiers and plan structures.

Resend Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Resend Rate Limits

5 limits

RATE LIMITS

FinOps 1

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

Resend Finops

FINOPS

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Resend Webhooks

AsyncAPI 2.6 description of the Resend webhook surface. Resend delivers webhook events to subscriber-configured HTTPS endpoints using Svix as the underlying delivery and signing...

ASYNCAPI

Semantic Vocabularies 1

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

Resend Context

21 classes · 0 properties

JSON-LD

Spectral Rules 3

Spectral governance rulesets for linting and validating these APIs.

Resend API Rules

6 rules · 1 errors 5 warnings

SPECTRAL

Resend API Rules

5 rules · 4 warnings 1 info

SPECTRAL

Resend API Rules

11 rules · 3 errors 6 warnings 2 info

SPECTRAL

JSON Schema 3

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

Resend Audience

4 properties

JSON SCHEMA

Resend Domain

7 properties

JSON SCHEMA

Resend Email

12 properties

JSON SCHEMA

JSON Structure 1

JSON Structure definitions describing this provider's data shapes.

Resend Email Structure

0 properties

JSON STRUCTURE

Examples 2

Example request and response payloads for these APIs.

Resend Create Audience Example

3 fields

EXAMPLE

Resend Send Email Example

4 fields

EXAMPLE

Security Posture 3

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

Resend Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resend Vulnerability Disclosure

security.txt · contact published

SECURITY

Resend Trust Center

SOC 2, ISO 27001, HIPAA, GDPR

SECURITY

Resources

Get Started 2

Portal, sign-up, and the first successful call

Login

Signup

Signup

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

MCPServer

MCPServer

AgentSkills

AgentSkills

LlmsText

LlmsText

Build 10

SDKs, sample code, and the tooling you integrate with

PostmanWorkspace

PostmanWorkspace

GitHubOrganization

Examples

SDKs

SDKs

SDKs

SDKs

SDKs

CLI

Library

Scroll for all 10

Access & Security 4

Authentication, authorization, and security posture

TrustCenter

TrustCenter

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Security

Security

Operate 4

Status, limits, changes, and where to get help

ChangeLog

Migrations

StatusPage

RateLimits

Commercial 1

Pricing, plans, and the legal terms of use

Pricing

Pricing

Company 4

The organization behind the API

Website

Website

LinkedIn

Blog

Blog

About

About

Other 1

Properties that don't map to a standard resource type

Customers

Customers

Source (apis.yml)

aid: resend
name: Resend
description: Resend is a developer-first email API platform that simplifies sending and managing transactional and marketing
  emails. It provides a clean REST API with bearer token authentication, supporting email sending, domain management, API
  key management, audience and contact management, and broadcast campaigns. Resend offers SDKs for Node.js, Python, Go, Ruby,
  PHP, Java, .NET, Rust, Elixir, and more, along with a React Email library and official MCP server.
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: 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/resend.png
tags:
- Email
- Developer Tools
- Transactional Email
- Marketing Email
url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/apis.yml
created: '2024-11-07'
modified: '2026-05-29'
specificationVersion: '0.23'
apis:
- aid: resend:resend-audiences-api
  name: Resend Audiences API
  description: Create and manage Audiences through the Resend API.
  humanURL: https://resend.com/
  baseURL: https://api.resend.com
  tags:
  - Audiences
  properties:
  - type: OpenAPI
    url: openapi/resend-audiences-api-openapi.yml
  - type: Documentation
    url: https://resend.com/
  - type: Webhooks
    url: https://resend.com/docs/dashboard/webhooks/introduction
  - type: AsyncAPI
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/asyncapi/resend-webhooks-asyncapi.yml
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-email-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-audience-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-domain-schema.json
  - type: JSONStructure
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-structure/resend-email-structure.json
  - type: JSONLDContext
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-ld/resend-context.jsonld
  - type: SpectralRules
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/rules/resend-rules.yml
  - type: Vocabulary
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/vocabulary/resend-vocabulary.yml
- aid: resend:resend-broadcasts-api
  name: Resend Broadcasts API
  description: The Broadcasts API from Resend — 2 operation(s) for broadcasts.
  humanURL: https://resend.com/
  baseURL: https://api.resend.com
  tags:
  - Broadcast
  tags_raw:
  - Broadcasts
  properties:
  - type: OpenAPI
    url: openapi/resend-broadcasts-api-openapi.yml
  - type: Documentation
    url: https://resend.com/
  - type: Webhooks
    url: https://resend.com/docs/dashboard/webhooks/introduction
  - type: AsyncAPI
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/asyncapi/resend-webhooks-asyncapi.yml
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-email-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-audience-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-domain-schema.json
  - type: JSONStructure
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-structure/resend-email-structure.json
  - type: JSONLDContext
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-ld/resend-context.jsonld
  - type: SpectralRules
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/rules/resend-rules.yml
  - type: Vocabulary
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/vocabulary/resend-vocabulary.yml
- aid: resend:resend-domains-api
  name: Resend Domains API
  description: Create and manage domains through the Resend API.
  humanURL: https://resend.com/
  baseURL: https://api.resend.com
  tags:
  - Domains
  properties:
  - type: OpenAPI
    url: openapi/resend-domains-api-openapi.yml
  - type: Documentation
    url: https://resend.com/
  - type: Webhooks
    url: https://resend.com/docs/dashboard/webhooks/introduction
  - type: AsyncAPI
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/asyncapi/resend-webhooks-asyncapi.yml
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-email-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-audience-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-domain-schema.json
  - type: JSONStructure
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-structure/resend-email-structure.json
  - type: JSONLDContext
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-ld/resend-context.jsonld
  - type: SpectralRules
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/rules/resend-rules.yml
  - type: Vocabulary
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/vocabulary/resend-vocabulary.yml
- aid: resend:resend-emails-api
  name: Resend Emails API
  description: Start sending emails through the Resend API.
  humanURL: https://resend.com/
  baseURL: https://api.resend.com
  tags:
  - Email
  tags_raw:
  - Emails
  properties:
  - type: OpenAPI
    url: openapi/resend-emails-api-openapi.yml
  - type: Documentation
    url: https://resend.com/
  - type: Webhooks
    url: https://resend.com/docs/dashboard/webhooks/introduction
  - type: AsyncAPI
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/asyncapi/resend-webhooks-asyncapi.yml
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-email-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-audience-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-domain-schema.json
  - type: JSONStructure
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-structure/resend-email-structure.json
  - type: JSONLDContext
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-ld/resend-context.jsonld
  - type: SpectralRules
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/rules/resend-rules.yml
  - type: Vocabulary
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/vocabulary/resend-vocabulary.yml
- aid: resend:resend-send-api
  name: Resend Send API
  description: The Send API from Resend — 1 operation(s) for send.
  humanURL: https://resend.com/
  baseURL: https://api.resend.com
  tags:
  - Send
  properties:
  - type: OpenAPI
    url: openapi/resend-send-api-openapi.yml
  - type: Documentation
    url: https://resend.com/
  - type: Webhooks
    url: https://resend.com/docs/dashboard/webhooks/introduction
  - type: AsyncAPI
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/asyncapi/resend-webhooks-asyncapi.yml
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-email-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-audience-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-domain-schema.json
  - type: JSONStructure
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-structure/resend-email-structure.json
  - type: JSONLDContext
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-ld/resend-context.jsonld
  - type: SpectralRules
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/rules/resend-rules.yml
  - type: Vocabulary
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/vocabulary/resend-vocabulary.yml
- aid: resend:resend-apis-api
  name: Resend APIS API
  description: The Apis API from Resend — 2 operation(s) for apis.
  humanURL: https://resend.com/
  baseURL: https://api.resend.com
  tags: []
  tags_raw:
  - Apis
  properties:
  - type: OpenAPI
    url: openapi/resend-apis-api-openapi.yml
  - type: Documentation
    url: https://resend.com/
  - type: Webhooks
    url: https://resend.com/docs/dashboard/webhooks/introduction
  - type: AsyncAPI
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/asyncapi/resend-webhooks-asyncapi.yml
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-email-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-audience-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-schema/resend-domain-schema.json
  - type: JSONStructure
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-structure/resend-email-structure.json
  - type: JSONLDContext
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/json-ld/resend-context.jsonld
  - type: SpectralRules
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/rules/resend-rules.yml
  - type: Vocabulary
    url: https://raw.githubusercontent.com/api-evangelist/resend/refs/heads/main/vocabulary/resend-vocabulary.yml
common:
- type: Website
  url: https://www.resend.com/
- type: PostmanWorkspace
  url: https://www.postman.com/kinlaneapi/resend/overview
- type: TrustCenter
  url: security/resend-trust-center.yml
- type: VulnerabilityDisclosure
  url: security/resend-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/resend-domain-security.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/resend
- url: https://github.com/resend
  name: GitHub Organization
  type: GitHubOrganization
- name: Changelog
  url: https://resend.com/changelog
  type: ChangeLog
- name: Blog
  url: https://resend.com/blog
  type: Blog
- name: Migration Guides
  url: https://resend.com/migrate
  type: Migrations
- name: Customers
  url: https://resend.com/customers
  type: Customers
- name: About
  url: https://resend.com/about
  type: About
- name: Security
  url: https://resend.com/security
  type: Security
- name: Integrations
  url: https://resend.com/docs/integrations
  type: Integrations
- name: Examples
  url: https://resend.com/docs/examples
  type: Examples
- name: SDKs
  url: https://resend.com/docs/sdks
  type: SDKs
- name: Pricing
  url: https://resend.com/pricing
  type: Pricing
- name: Login
  url: https://resend.com/login
  type: Login
- name: Sign Up
  url: https://resend.com/signup
  type: Signup
- name: Node.js SDK
  url: https://github.com/resend/resend-node
  type: SDKs
- name: Python SDK
  url: https://github.com/resend/resend-python
  type: SDKs
- name: Go SDK
  url: https://github.com/resend/resend-go
  type: SDKs
- name: .NET SDK
  url: https://github.com/resend/resend-dotnet
  type: SDKs
- name: CLI
  url: https://github.com/resend/resend-cli
  type: CLI
- name: MCP Server
  url: https://github.com/resend/resend-mcp
  type: MCPServer
- name: React Email
  url: https://github.com/resend/react-email
  type: Library
- name: Status
  url: https://resend-status.com/
  type: StatusPage
- name: Rate Limits
  url: https://resend.com/docs/api-reference/introduction
  type: RateLimits
- name: Agent Skills
  url: https://github.com/resend/resend-skills
  type: AgentSkills
- type: LlmsText
  url: https://resend.com/llms.txt
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

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