Docs

Other languages

Go, Ruby, PHP, Java, C#, and anything else: the API over plain HTTPS.

There is nothing special about the SDKs. The API is JSON over HTTPS with a bearer token, so any language with an HTTP client is a first-class client. The examples below all do the same thing: send one message. Everything else in /docs/rest works the same way.

Go

main.go 
package main

import (
	"bytes"
	"encoding/json"
	"net/http"
	"os"
)

func main() {
	body, _ := json.Marshal(map[string]any{
		"to":      []string{"jane@acme.com"},
		"subject": "Your quote",
		"body":    "Attached, as promised.",
	})

	req, _ := http.NewRequest("POST", "https://mcpmailer.com/v1/messages", bytes.NewReader(body))
	req.Header.Set("Authorization", "Bearer "+os.Getenv("MCPMAILER_API_KEY"))
	req.Header.Set("Content-Type", "application/json")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
}

Ruby

send.rb 
require "net/http"
require "json"

uri = URI("https://mcpmailer.com/v1/messages")
res = Net::HTTP.post(uri, {
  to: ["jane@acme.com"],
  subject: "Your quote",
  body: "Attached, as promised."
}.to_json, {
  "Authorization" => "Bearer #{ENV['MCPMAILER_API_KEY']}",
  "Content-Type" => "application/json"
})

puts JSON.parse(res.body)["messageId"]

PHP

send.php 
<?php
$res = file_get_contents('https://mcpmailer.com/v1/messages', false, stream_context_create([
  'http' => [
    'method' => 'POST',
    'header' => "Authorization: Bearer " . getenv('MCPMAILER_API_KEY') . "\r\n" .
                "Content-Type: application/json\r\n",
    'content' => json_encode([
      'to' => ['jane@acme.com'],
      'subject' => 'Your quote',
      'body' => 'Attached, as promised.',
    ]),
  ],
]));

echo json_decode($res, true)['messageId'];

Anything else

Java, C#, Rust, Elixir, and the rest follow the same three rules: POST JSON, set the Authorization header, and read the status field on the response. /openapi.json is a complete OpenAPI 3.1 description, so a generated client is a reasonable option too.

the same call, as curl 
curl https://mcpmailer.com/v1/messages \
  -H "Authorization: Bearer mmk_live_..." \
  -H "Content-Type: application/json" \
  -d '{
    "to": ["ada@example.com"],
    "subject": "Shipping update",
    "body": "The parts landed this morning."
  }'

A 200 means the message went out. A 422 with a status field is a refusal you can act on, not a transport failure, so treat it as a result and read reason. A 429 carries retry-after in seconds.

JSON 
{
  "status": "sent",
  "messageId": "msg_01J9X8Q2K7"
}