OpenAPI and other languages

The full API is described by an OpenAPI 3.1 document. It drives the API reference on this site and can generate clients for languages without an official SDK.

• Spec: https://api.spacepost.dev/openapi.json
• Source file in the repository: openapi/openapi.yaml

Generate a client

Set the base URL to https://api.spacepost.dev and configure bearer authentication with your sp_live_ key.

TypeScript

Types and a fetch client with openapi-typescript and openapi-fetch:

npx openapi-typescript https://api.spacepost.dev/openapi.json -o spacepost.d.ts
npm install openapi-fetch

import createClient from "openapi-fetch";
import type { paths } from "./spacepost";

const client = createClient<paths>({
  baseUrl: "https://api.spacepost.dev",
  headers: { Authorization: `Bearer ${process.env.SPACEPOST_API_KEY}` },
});

const { data, error } = await client.POST("/emails", {
  body: { from: "Acme <hello@acme.com>", to: ["user@example.com"], subject: "Hi", html: "<p>Hi</p>" },
});

Python

pipx install openapi-python-client
openapi-python-client generate --url https://api.spacepost.dev/openapi.json

Go

go install github.com/oapi-codegen/oapi-codegen/v2/cmd/oapi-codegen@latest
curl -s https://api.spacepost.dev/openapi.json -o openapi.json
oapi-codegen -package spacepost -generate types,client openapi.json > spacepost.gen.go

Any language

Use OpenAPI Generator:

npx @openapitools/openapi-generator-cli generate \
  -i https://api.spacepost.dev/openapi.json \
  -g ruby -o ./spacepost-ruby

Generators exist for PHP, Ruby, Java, Kotlin, Swift, C#, Rust and dozens more.

Tip

Generated clients do not know that errors share one shape, or about Idempotency-Key. Add that header to your client’s default or per-request headers where you need it, and parse errors as { statusCode, name, message }.

Postman and API tools

Import the spec URL into Postman, Insomnia, Bruno or Hoppscotch. Set a collection variable for the bearer token.

Use the Resend SDKs

Because SpacePost is Resend-compatible, official Resend SDKs in other languages often work by overriding their base URL. See Migrating from Resend.

API referenceEvery endpoint with request and response schemas.