---
title: "PAYG Email API For Every Stage Of Growth"
description: "Discover AhaSend's Pay-as-you-go (usage-based) Email API for fast, reliable email delivery. Enjoy advanced features like real-time tracking, email routing, and domain protection. Perfect for e-commerce, SaaS, and more."
url: https://ahasend.com/payg-usage-based-email-api
markdown_url: https://ahasend.com/payg-usage-based-email-api.md
lang: en
type: page_builder
published: 2025-12-16
updated: 2026-09-02
---

# PAYG Email API For Every Stage Of Growth

Begin with **1000 free monthly emails**. Move to Pro or Max to unlock usage-based pricing that grows with your email volume.

- [Start Now For Free](https://dash.ahasend.com/user/register)
- [Pricing](https://ahasend.com/pricing)

## Start sending emails in minutes

Our APIs come with OpenAPI specs for easy and fast integration

### CLI

#### cURL

```bash
curl --request POST \
  --url https://api.ahasend.com/v2/accounts/{account_id}/messages \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'Idempotency-Key: UNIQUE-KEY' \
  --data '{
    "from": {
      "email": "noreply@example.com",
      "name": "Example Corp"
    },
    "recipients": [
      {
        "email": "user@example.com",
        "name": "John Doe"
      }
    ],
    "subject": "Welcome to Example Corp",
    "html_content": "<h1>Welcome {{first_name}}!</h1>",
    "text_content": "Welcome {{first_name}}!",
    "substitutions": {
      "first_name": "John"
    }
  }'
```

#### AhaSend CLI

```bash
ahasend messages send \
  --account-id YOUR-ACCOUNT-ID \
  --api-key 'aha-sk-YOUR-API-KEY' \
  --from noreply@awesomeinc.com \
  --to recipient@email.com \
  --subject "Welcome to AhaSend" \
  --html "<h1>Welcome!</h1><p>Thank you for using AhaSend.</p>"
```

Need help getting started? [Check out our documentation](https://ahasend.com/docs) or [contact our support team](https://ahasend.com/contact)

### Go

#### Go

```go
package main

import (
  "context"

  "github.com/AhaSend/ahasend-go"
  "github.com/AhaSend/ahasend-go/api"
  "github.com/AhaSend/ahasend-go/models/common"
  "github.com/AhaSend/ahasend-go/models/requests"
  "github.com/google/uuid"
)

func main() {
  client := api.NewAPIClient(
    api.WithAPIKey("aha-sk-your-64-character-key"),
  )

  accountID := uuid.New()
  ctx := context.Background()

  // SDK automatically handles Idempotency and retries
  client.MessagesAPI.CreateMessage(
    ctx,
    accountID,
    requests.CreateMessageRequest{
      From: common.SenderAddress{
        Email: "info@example.com",
        Name:  ahasend.String("Example Corp."),
      },
      Recipients: []common.Recipient{
        {
          Email: "john@example.com",
          Name:  ahasend.String("John Smith"),
        },
      },
      Subject:     "Hello",
      TextContent: ahasend.String("Hello world!"),
      Sandbox:     ahasend.Bool(true),
    },
  )
}
```

Need help getting started? [Check out our documentation](https://ahasend.com/docs) or [contact our support team](https://ahasend.com/contact)

### JavaScript

Install dependencies:

```bash
npm install @ahasend/sdk
```

#### Node.js

```javascript
import { AhaSendClient } from "@ahasend/sdk";

const ahasend = new AhaSendClient({
  apiKey: process.env.AHASEND_API_KEY,
  accountId: process.env.AHASEND_ACCOUNT_ID,
});

const result = await ahasend.messages.send({
  from: { email: "hello@yourdomain.com", name: "Your App" },
  recipients: [{ email: "user@example.com", name: "Jane" }],
  subject: "Welcome to Your App",
  html_content: "<h1>Welcome aboard</h1>",
  text_content: "Welcome aboard",
  sandbox: true, // validates and queues without delivering
});

const accepted = result.data.filter((entry) =>
  entry.status === "queued" || entry.status === "scheduled"
);
const rejected = result.data.length - accepted.length;
if (rejected > 0 || accepted.length === 0) {
  console.error("AhaSend rejected recipients", { count: rejected });
  process.exitCode = 1;
} else {
  console.log("Sandbox messages accepted", { count: accepted.length });
}
```

Need help getting started? [Check out our documentation](https://ahasend.com/docs) or [contact our support team](https://ahasend.com/contact)

### Python

#### Python

```python
import requests

url = "https://api.ahasend.com/v2/accounts/{account_id}/messages"

payload = {
    "from": {
        "email": "noreply@example.com",
        "name": "Example Corp"
    },
    "recipients": [
        {
            "email": "user@example.com",
            "name": "John Doe",
            "substitutions": { "first_name": "John" }
        }
    ],
    "subject": "Welcome to Example Corp",
    "html_content": "<h1>Welcome {{first_name}}!</h1>",
    "text_content": "Welcome {{first_name}}!"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json",
    "Idempotency-Key": "UNIQUE-KEY",
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())
```

Need help getting started? [Check out our documentation](https://ahasend.com/docs) or [contact our support team](https://ahasend.com/contact)

### PHP

#### PHP

```php
<?php
$email = [
  'from' => [
    'email' => 'noreply@example.com',
    'name' => 'Example Corp'
  ],
  'recipients' => [
    [
      'email' => 'user@example.com',
      'name' => 'John Doe',
      'substitutions' => [
        'first_name' => 'John'
      ]
    ]
  ],
  'subject' => 'Welcome to Example Corp',
  'html_content' => '<h1>Welcome {{first_name}}!</h1>',
  'text_content' => 'Welcome {{first_name}}!',
];
$headers = [
  'Content-type: application/json',
  'Authorization: Bearer <token>',
  'Idempotency-Key: UNIQUE-KEY'
];
$options = [
  'http' => [
    'header'  => implode("\r\n", $headers),
    'method'  => 'POST',
    'content' => json_encode($email)
  ]
];
$context  = stream_context_create($options);
$resp = file_get_contents('https://api.ahasend.com/v2/account/{account_id}/messages', FALSE, $context);
var_export($resp, TRUE);
```

#### Symfony

```php
<?php
// Using Symfony Mailer with AhaSend Bridge
// See: https://github.com/symfony/aha-send-mailer

use Symfony\Component\Mailer\MailerInterface;
use Symfony\Component\Mime\Email;

class EmailService
{
    public function __construct(
        private MailerInterface $mailer
    ) {}

    public function sendWelcomeEmail(string $userEmail, string $firstName): void
    {
        $email = (new Email())
            ->from('noreply@example.com')
            ->to($userEmail)
            ->subject('Welcome to Example Corp')
            ->html('<h1>Welcome {{first_name}}!</h1>')
            ->text('Welcome {{first_name}}!')
            ->getHeaders()
            ->addTextHeader('X-AhaSend-Substitutions', json_encode([
                'first_name' => $firstName
            ]));

        $this->mailer->send($email);
    }
}

// Configuration in .env:
// MAILER_DSN=ahasend+api://API_KEY@default
```

Need help getting started? [Check out our documentation](https://ahasend.com/docs) or [contact our support team](https://ahasend.com/contact)

### Ruby

#### Ruby

```ruby
require 'uri'
require 'net/http'
require 'json' # Required to convert the hash to a JSON string

url = URI("https://api.ahasend.com/v2/accounts/{account_id}/messages")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request["Idempotency-Key"] = 'UNIQUE-KEY'

# Create a Ruby hash object for the request body
payload = {
  from: {
    email: "noreply@example.com",
    name: "Example Corp"
  },
  recipients: [
    {
      email: "user@example.com",
      name: "John Doe",
      substitutions: {
        first_name: "John"
      }
    }
  ],
  subject: "Welcome to Example Corp",
  html_content: "<h1>Welcome {{first_name}}!</h1>",
  text_content: "Welcome {{first_name}}!"
}

# Encode the Ruby hash into a JSON string for the request body
request.body = payload.to_json

response = http.request(request)
puts response.read_body
```

#### Rails

```ruby
# Using Rails ActionMailer with AhaSend configuration
# config/environments/production.rb

config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  address: 'smtp.ahasend.com',
  port: 587,
  domain: 'yourdomain.com',
  user_name: 'your_smtp_username',
  password: 'your_smtp_password',
  authentication: 'plain',
  enable_starttls_auto: true
}

# app/mailers/application_mailer.rb
class ApplicationMailer < ActionMailer::Base
  default from: 'noreply@example.com'
  layout 'mailer'
end

# app/mailers/welcome_mailer.rb
class WelcomeMailer < ApplicationMailer
  def welcome_email(user)
    @user = user
    @first_name = user.first_name

    mail(
      to: @user.email,
      subject: 'Welcome to Example Corp',
      template_name: 'welcome'
    )
  end
end

# Usage:
WelcomeMailer.welcome_email(user).deliver_now
```

Need help getting started? [Check out our documentation](https://ahasend.com/docs) or [contact our support team](https://ahasend.com/contact)

## Fair and simple usage-based pricing

Usage-based, Pay As You Go (PAYG) Pricing plan, so that you only pay for what you use.

- Free for the first 1000 emails / month
- $10 (€9 / £8) / month for 25,000 emails included
- Pay-as-you-go pricing (volume discounts apply)

[Check Pricing](https://ahasend.com/pricing)

### Features

Thoughtfully crafted for sending transactional emails at any scale

- Unlimited domains
- Unlimited team members
- Unlimited webhooks
- Unlimited message routes
- RESTful APIs & SMTP relay
- Open and click tracking
- Customizable retention policies (up to 30 days)
- Automated bounce and blocklist management
- Automated SPAM monitoring
- Priority support

---

### Ensure Reliable and Fast Email Delivery

With millions of emails delivered each month, AhaSend offers fast, reliable email delivery. Our focus on transactional emails ensures industry-leading speed and optimized inbox placement.

- Proven track record with millions of emails sent monthly
- Industry-leading delivery times for faster communication
- Optimized for fast transactional email delivery
- Enhanced inbox placement for critical emails

### Detailed Insights on Email Performance

Get full visibility into your email performance with AhaSend's detailed reporting tools. From delivery times to bounce reasons, our reports provide the data you need to optimize every campaign.

- Real-time tracking for sent emails
- Monitor delivery times and status updates
- Detailed bounce reason reports to improve future sends

### Stay Informed with Webhook Alerts

Stay up-to-date with real-time notifications using AhaSend's Webhooks. Receive instant updates on delivery events, so you're always informed about the status of your emails, from sent to delivered and everything in between.

- Real-time alerts for email delivery events
- Track statuses like queued, delivered, bounced, opened, clicked and more
- Easily integrate with your apps and dashboards for seamless email experience

### Seamlessly Integrate Incoming Emails into Apps

AhaSend's Email Routing feature allows you to automatically direct incoming emails to the right applications. By parsing and forwarding messages based on predefined criteria, you can streamline workflows and enhance automation within your system.

- Parse incoming emails and extract key data
- Route messages to specific applications or endpoints
- Separate replies from quoted text
- Customize routing rules to fit your unique needs

### Safeguard Your Domain and Deliverability

AhaSend helps protect your sending domain with best-in-class tools for DNS configuration and monitoring. With automated setup and real-time monitoring, we ensure your domain's reputation stays intact, enhancing deliverability and preventing errors that can impact inbox placement.

- Enforce best practices for DNS setup to optimize deliverability
- Automated DNS configuration in seconds
- Continuous monitoring of domain and DNS status
- Proactive alerts to prevent reputation damage from misconfigurations

### Keep Your Email Data Safe and Compliant

At AhaSend, email security is a top priority. Our customizable retention policies and automated blocking features protect your email data while keeping you compliant with privacy standards. Reduce risks and safeguard your communications with proactive security measures designed to prevent threats like typo-squatting and toxic domain activity.

- Customizable data retention periods to meet compliance needs
- Automated blocking of emails to tempmail and suspicious/toxic domains
- Prevention of typo-squatting attacks by filtering domains with typos

_Industry-specific use cases_

## How Businesses Use AhaSend's Email API

AhaSend's transactional email solutions are tailored to meet the unique needs of various industries. Whether you're in e-commerce, SaaS, or fintech, our flexible API supports seamless integration and reliable email delivery, helping you communicate effectively with your users.

- [Sign Up Free](https://dash.ahasend.com/user/register)

### E-commerce

Send order confirmations, shipping updates, and personalized notifications to enhance customer experience and boost engagement.

### SaaS

Manage user authentication, account notifications, and feature updates with ease using our reliable API for smooth, timely communication.

### Social Networks

Deliver notifications, friend requests, and activity updates to keep users connected and engaged on your platform.

### Recruitment Job Boards

Send job alerts, application updates, and interview reminders to streamline the hiring process for candidates and recruiters.

### Online Education Platforms

Automate course enrollment confirmations, assignment notifications, and progress reports to improve student engagement and retention.

### Fintech and Financial Services

Provide real-time transaction alerts, account updates, and security notifications for a seamless customer experience.

### Support and Ticketing Systems

Ensure prompt response times by automating ticket confirmations, status updates, and resolution notifications.

### Booking and Reservations

Send booking confirmations, reminders, and cancellation notifications to keep customers informed and satisfied.

### Real Estate Platforms

Automate property alerts, appointment confirmations, and follow-up emails to keep buyers, renters, and agents informed throughout the property search and transaction process.

## Join Thousands Of Developers Using AhaSend

Start sending emails with our reliable SMTP server. No complex setup required, just plug and play.

- [Get Started For Free](https://dash.ahasend.com/user/register)