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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.

agent ready

Solid contracts, transparent operations, and an easy start — typically complete on four or five facets with one clear soft spot.

Kin Score

API Evangelist profiles Resend the way a machine reads it — 37 machine-readable artifacts across 13 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.

Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Resend scores 64.0/100 (strong), with a separate agent-readiness read of 53/100 (agent ready). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.

Kin Score

This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.

Kin Score Kin Score How this is scored →
scored 2026-07-27 · rubric v0.5
Composite quality — 64.0/100 · strong
Contract Quality 17.9 / 25
Developer Ergonomics 6.5 / 20
Commercial Clarity 14.2 / 20
Operational Transparency 10.3 / 13
Governance 6.3 / 12
Discoverability 8.8 / 10
Agent readiness — 53/100 · agent ready
Machine-Readable Contract 18 / 18
Agentic Access Contract 0 / 15
MCP Server 12 / 12
Machine-Readable Auth 0 / 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

How we profile Resend

Each block below is one kind of artifact we hold for Resend. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.

APIs 13

Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.

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

Resend Apis API

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

Resend Audience API

The Audience API from Resend — 3 operation(s) for audience.

Resend Audiences API

Create and manage Audiences through the Resend API.

Resend Batch API

The Batch API from Resend — 1 operation(s) for batch.

Resend Broadcasts API

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

Resend Cancel API

The Cancel API from Resend — 1 operation(s) for cancel.

Resend Contacts API

Create and manage Contacts through the Resend API.

Resend Domains API

Create and manage domains through the Resend API.

Resend Email API

The Email API from Resend — 3 operation(s) for email.

Resend Emails API

Start sending emails through the Resend API.

Resend Keys API

The Keys API from Resend — 2 operation(s) for keys.

Resend Send API

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

Resend Verify API

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

Scroll within the panel for all 13 ·

MCP Servers 1

Model Context Protocol servers expose these APIs directly to AI agents. We profile them because agent-native access is the fastest-growing way this provider's capabilities actually get used.

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

MCP Server

MCP SERVER

Agent Skills 5

An agent skill packages the how-to for driving these APIs from an assistant — the prompts, the sequence, the guardrails — so the knowledge to use the API travels with it.

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

agent-email-inbox

AGENT SKILL

react-email

AGENT SKILL

resend-cli

AGENT SKILL

resend

AGENT SKILL

GraphQL 1

Where a provider ships GraphQL, the schema is the contract. We profile it alongside the REST surface so the whole interface is legible in one place.

GraphQL schemas published by this provider.

Resend GraphQL Schema

Resend is a developer-first email API platform for sending and managing transactional and marketing emails. Resend's public API is REST-based; this GraphQL schema is a conceptua...

GRAPHQL

Pricing Plans 1

Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the six things the Kin Score reads for commercial clarity.

Published pricing tiers and plan structures.

Resend Plans Pricing

3 plans

PLANS

Rate Limits 1

Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.

Documented rate limits and quota policies.

Resend Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.

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

Event Specifications 1

Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.

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 give the data shared meaning across APIs. We profile them because semantics are what let a machine reconcile 'customer' here with 'customer' somewhere else.

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

Resend Context

21 classes · 0 properties

JSON-LD

Spectral Rules 3

Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.

Resend API Rules

6 rules · 1 errors · 5 warnings

SPECTRAL

Resend API Rules

5 rules · 4 warnings

SPECTRAL

Resend API Rules

11 rules · 3 errors · 6 warnings

SPECTRAL

JSON Schema 3

Standalone JSON Schema definitions describe the data models behind the API. We profile them so the shapes are validatable on their own — useful long after a single request is forgotten.

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 captures the data shapes in a form built for tooling — a complement to JSON Schema that keeps the model machine-legible.

JSON Structure definitions describing this provider's data shapes.

Resend Email Structure

0 properties

JSON STRUCTURE

Examples 2

Real request and response payloads are what turn a spec from abstract into obvious — and they're one of the twelve things an agent needs to call an API correctly on the first try.

Example request and response payloads for these APIs.

Security Posture 3

Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.

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

Every other property we hold for Resend — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.

Get Started 2

Portal, sign-up, and the first successful call

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

Commercial 1

Pricing, plans, and the legal terms of use

Company 3

The organization behind the API

Other 1

Properties that don't map to a standard resource type

← All providers · Data indexed from github.com/api-evangelist/resend · machine-readable index on apis.io