Sendkit vs Mailgun: a practical comparison

Mailgun launched in 2010 and quickly became the go-to email API for developers. It earned that reputation. The API was solid, the docs were good enough, and it just worked. But email infrastructure has moved on, and Mailgun hasn't kept pace. The API design feels stuck in 2015, the pricing has gotten confusing, and if you need anything beyond basic sending and validation, you're stitching together multiple tools.

Sendkit was built to be the platform Mailgun should have become: a single API for sending, campaigns, automations, contacts, and validation. No per-contact fees. SDKs that feel like they were designed this decade.

This is a direct, practical comparison. No fluff.

API and developer experience

This is where the gap is widest. Mailgun's API is mature and well-documented, but it uses form-encoded request bodies by default. In 2026, that's a weird choice. Most developers expect JSON in, JSON out. Mailgun supports JSON, but it feels like an afterthought.

Here's sending an email with Mailgun:

import formData from 'form-data';
import Mailgun from 'mailgun.js';

const mg = new Mailgun(formData);
const client = mg.client({ username: 'api', key: 'your-api-key' });

const send = async () => {
  const result = await client.messages.create('yourdomain.com', {
    from: '[email protected]',
    to: ['[email protected]'],
    subject: 'Welcome',
    html: '<p>Thanks for signing up.</p>',
  });
};

Notice the form-data dependency. That's a Mailgun quirk. You need a third-party form encoding library just to initialize the client. It's a small thing, but it signals how the SDK was built: around the API's legacy constraints instead of around what developers actually want.

Here's the same thing with Sendkit:

import { Sendkit } from '@sendkitdev/sdk';

const sendkit = new Sendkit('sk_live_your_api_key');

const send = async () => {
  const { data, error } = await sendkit.emails.send({
    from: '[email protected]',
    to: '[email protected]',
    subject: 'Welcome',
    html: '<p>Thanks for signing up.</p>',
  });
};

No extra dependencies. JSON in, { data, error } out. The response pattern is predictable across every endpoint, which means you write less defensive code.

Sendkit ships official SDKs for 10 languages: Node.js, Python, Ruby, Go, PHP, Java, Rust, Elixir, C#, and Kotlin. Each one follows the conventions of its language instead of being a thin HTTP wrapper. Mailgun has official libraries for a handful of languages, but several are community-maintained with varying quality.

Features

This is where the comparison gets lopsided. Mailgun is fundamentally a sending and validation service. That's the core, and it does those things well. But the moment you need campaigns, contact management, or automations, you're adding another provider.

Here's the feature breakdown:

Feature	Mailgun	Sendkit
Transactional email	Yes	Yes
Email campaigns	No	Yes
Automations	No	Yes
Contact management	No	Yes
Email validation	Yes (separate pricing)	Yes (included)
Inbound routing	Yes	Planned
SMTP relay	Yes	Yes
Webhooks	Yes	Yes
Suppression lists	Manual	Auto-managed

Mailgun does offer inbound routing, which is a genuine advantage if you need to parse incoming email. Sendkit doesn't have that yet. But for outbound email — which is what 90% of developers actually need — Sendkit covers far more ground from a single integration.

The practical consequence: with Mailgun, you typically end up paying for Mailgun plus Mailchimp or Customer.io or some other tool for campaigns and automations. With Sendkit, you wire up one API key and you're done. That's not just a cost saving; it's an architecture simplification. One set of webhooks, one dashboard, one suppression list, one billing relationship.

Pricing

Mailgun's pricing has gotten complicated over the years. There are four tiers (Trial, Foundation, Scale, Custom), and the feature gates between them are not intuitive. Want custom DKIM? That's Scale tier. Want dedicated IPs? Also Scale. Email validation is billed entirely separately with its own pricing page.

Here's a rough comparison at common volumes:

Volume	Mailgun (Foundation)	Sendkit
3,000/month	$0 (trial, limited)	$0 (free tier)
10,000/month	$35/month	$15/month
50,000/month	$90/month	$60/month
100,000/month	$175/month	$100/month

Sendkit's pricing is volume-based. You pick a plan based on how many emails you send. That's it. No per-contact fees, no separate charges for validation, no feature gates behind higher tiers. Every plan includes campaigns, automations, contacts, and validation.

Mailgun charges for email validation on top of your sending plan. If you're validating addresses at signup — which you should be, and we've written about why — that adds up. On Sendkit, validation is part of the platform. Check out our pricing page for exact numbers.

Deliverability

Both platforms handle the fundamentals: SPF, DKIM, DMARC configuration through DNS records. If you haven't set those up yet, our guide on setting up DMARC, DKIM, and SPF walks through the process.

Mailgun provides suppression list management, but it's manual. You need to handle bounces and complaints through webhooks and update your lists accordingly. If you don't, you keep sending to bad addresses, your sender reputation drops, and your deliverability tanks. We've covered the full picture in our deliverability guide.

Sendkit auto-manages suppression lists. When an email bounces or a recipient marks you as spam, that address is automatically suppressed. You don't need to build webhook handlers to maintain list hygiene — it happens by default. You can still manually manage suppressions through the API or dashboard, but the point is you don't have to.

Both platforms support dedicated IPs for high-volume senders. Both let you track opens, clicks, bounces, and complaints through webhooks and dashboards.

The real deliverability difference isn't a single feature; it's how many footguns each platform lets you step on. Mailgun gives you the tools and expects you to use them correctly. Sendkit has more guardrails baked in.

SMTP support

Both Mailgun and Sendkit support SMTP, which matters if you're integrating with legacy systems, WordPress, or any tool that doesn't support REST APIs natively.

Mailgun's SMTP setup is straightforward: point your SMTP client at smtp.mailgun.org with your credentials. Sendkit works the same way with smtp.sendkit.com. If you're deciding between SMTP and a proper API integration, we compared the tradeoffs in SMTP vs email API.

For new projects, use the API. SMTP is fine for compatibility, but you lose features like metadata tagging, template rendering, and proper error handling. Both platforms will tell you the same thing.

Who Mailgun is still good for

Mailgun isn't a bad product. It's a mature, reliable sending service. If you only need transactional email and validation, and you've already got campaigns and contacts handled elsewhere, Mailgun will work. It's also the better choice today if you need inbound email parsing — Sendkit doesn't offer that yet.

If you're already on Mailgun and everything works, migrating for the sake of migrating is dumb. But if you're hitting limitations — bolting on extra tools for campaigns, fighting the SDK, paying more than you need to for validation — that's when the switch makes sense.

Who Sendkit is built for

Sendkit is for developers and teams who want one platform for email. Not just sending, but the entire lifecycle: transactional email, campaigns, automations, contact management, and validation. All accessible through a single API with clean SDKs.

It's also for teams who don't want to think about email infrastructure more than they have to. Auto-managed suppression lists, built-in validation, simple pricing — these are deliberate design choices to reduce the operational surface area of email.

Verdict

Mailgun works. It has for over 15 years. But it feels like a product that peaked in 2018 and has been coasting on inertia since. The API design is dated, the pricing is unnecessarily complex, and the feature set forces you into a multi-vendor setup for anything beyond basic sending.

Sendkit gives you a modern API, broader features under one roof, and simpler pricing. The DX is noticeably better — from the SDKs to the dashboard to the docs. If you're starting a new project or evaluating a switch, Sendkit is the stronger choice.

Try the free tier — 3,000 emails per month, no credit card required. You'll have emails sending in under five minutes.