Starter
For your first email program.
$16USD / month
$192 billed yearly.
20,000 emails / month
Choose Starter- 5 brands · 3 seats
- 5 custom sending domains
- 500 email verifications/month
- $1.50 / 1,000 extra emails
Nitrosend is the best Mailgun alternative for teams that run email from an AI agent over MCP, with the top score of 83.75 out of 100 of the eight reviewed here, and 9 out of 10 on working from your AI assistant, the heaviest test. Most teams leaving Mailgun are missing the layer above the sending, and Nitrosend is that layer. Your receipts, newsletters and automated flows go out on one plan and one bill, and you see all of them in one place. It is the only one of the eight here your AI assistant, whether Claude, ChatGPT, Cursor or Codex, can sign up to and send from without anyone opening a dashboard, and it writes every email in your brand's colors, fonts and voice. It costs $20 a month for 20,000 emails and $650 for a million emails on Scale including overage. Resend comes next at 77.5, then Bird (formerly SparkPost) at 76. To send email from an AI agent with Nitrosend, add its MCP server at api.nitrosend.com/mcp to Claude, ChatGPT, Cursor or Codex and sign in with OAuth: a transactional email goes out on the call, and a campaign or flow waits as a draft until it is approved.
The ranking
Rank 1Nitrosend
83.75 out of 100Total
- Priced by
- Emails sent
- Free plan
- 5,000 emails, then 500 a month
- Entry plan
- $20 a month, 20,000 emails
- Works from your AI assistant9 out of 10Official MCP server, account signup over the API and a ready-made sender, so an agent sends with no dashboard (docs).
- Receipts and newsletters on one plan9 out of 10Receipts, campaigns and flows share one plan, one API and one allowance, on separate streams (pricing).
- Emails in your brand, no designer9 out of 10Brand Kit reads your site for logo, colors, fonts and voice, and every drafted email uses it (docs).
- Free plan7 out of 105,000 emails up front, then 500 every month, no card and no expiry (pricing).
- Price8.5 out of 10$20 a month for 20,000 emails on Starter and $650 for a million emails on Scale including overage, with unlimited contacts on every plan (pricing).
- Developer tools10 out of 10REST API with an OpenAPI spec, a typed TypeScript SDK, a CLI, an MCP server, signed event webhooks, idempotent sends and test sends (docs).
- Track record and support4 out of 10A young product from a small team. Dedicated IPs available as a provisioned add-on on Scale or Enterprise, a 99.9% SLA only on Enterprise (pricing).
Nitrosend
Ask your agent for the next campaign
Connect Nitrosend to Claude, ChatGPT, Cursor or Codex, point Brand Kit at your site, and describe the email. Contacts are unlimited on every plan.
Free: 5,000 emails to start, then 500 a month. No credit card.
Start free
Rank 2Resend
77.5 out of 100Total
- Priced by
- Emails sent, plus contacts for marketing
- Free plan
- 3,000 emails a month, 100 a day
- Entry plan
- $20 a month, 50,000 emails
- Works from your AI assistant8 out of 10Hosted MCP server with OAuth, plus agent plugins and a CLI, but a person creates the account and verifies a domain (docs).
- Receipts and newsletters on one plan7 out of 10Broadcasts and automations share the account and API, but marketing is a second plan priced by contacts (pricing).
- Emails in your brand, no designer6 out of 10An AI writer in the editor with URL and brand analysis listed, and React Email for coded templates (pricing).
- Free plan8 out of 103,000 emails a month, up to 100 a day, on a free plan that does not expire (pricing).
- Price9 out of 10$20 a month for 20,000 emails on Pro, the same as Nitrosend, but $650 for a million on Scale (pricing).
- Developer tools9 out of 10Official SDKs, an SMTP relay, webhooks, inbound email, React Email and a CLI on every plan (pricing).
- Track record and support6 out of 10Newer than the incumbents, with SOC 2 Type II, dedicated IPs on Scale and a 99.99% SLA on Enterprise (pricing).
Rank 3Bird (formerly SparkPost)
76 out of 100Total
- Priced by
- Emails sent
- Free plan
- 1,000 emails a month, no expiry
- Entry plan
- $15 a month, 50,000 emails
- Works from your AI assistant8 out of 10Hosted MCP server at mcp.bird.com with OAuth and a CLI, and an agent can sign itself up from the terminal, but it must read an emailed code, and it can only test-send until a sending domain is verified (signup, sandbox).
- Receipts and newsletters on one plan7 out of 10Broadcasts and single sends draw on one email allowance and one bill, with no contact fee. Email automations are in early access, built in the dashboard, with a separate run allowance (automation).
- Emails in your brand, no designer4 out of 10Templates with versions and translations, and React Email rendering. You supply the design (product).
- Free plan6 out of 101,000 emails a month with no time limit and no card, capped at 50 a day (pricing).
- Price10 out of 10$15 a month for 20,000 emails on Startup, and $530 for a million on Growth (pricing).
- Developer tools9 out of 10SDKs for Node, Python, PHP and Go, an SMTP relay, event webhooks, inbound relay webhooks, suppression and a sandbox (API).
- Track record and support7 out of 10SparkPost infrastructure since 2014, now sold as Bird. Dedicated IPs $24.95 each on Growth and above. No SLA on the pricing page (pricing).
Rank 4Mailtrap
74 out of 100Total
- Priced by
- Emails sent, plus contacts for marketing
- Free plan
- 4,000 emails a month, 150 a day
- Entry plan
- $15 a month, 10,000 emails
- Works from your AI assistant6 out of 10Official MCP server, CLI and agent skills, run with an API token after a person signs up (docs).
- Receipts and newsletters on one plan7 out of 10Campaigns, contacts and automations sit in the same platform, on a second plan priced by contacts (pricing).
- Emails in your brand, no designer5 out of 10A drag-and-drop and HTML template builder with Handlebars, but the brand design is yours to build (docs).
- Free plan8 out of 104,000 emails a month, up to 150 a day, on a free plan with one sending domain (pricing).
- Price9 out of 10$20 a month for 20,000 emails on Basic, which covers 50,000, and $750 for the Enterprise 1.5 million step, since Business stops at 750,000 (pricing).
- Developer tools10 out of 10SDK guides for ten languages, SMTP, webhooks, inbound email, a CLI and a full email testing sandbox (docs).
- Track record and support7 out of 10Grew out of its email testing product. A dedicated IP on Business, a separate bulk stream and reputation alerts (pricing).
Rank 5MailerSend
68.5 out of 100Total
- Priced by
- Emails sent
- Free plan
- 500 emails a month, card required
- Entry plan
- $7 a month, 5,000 emails (Hobby)
- Works from your AI assistant8 out of 10Hosted MCP server connected by OAuth that sends and schedules email, sets up domains and webhooks and reads email activity, once a person has signed up (docs).
- Receipts and newsletters on one plan4 out of 10Bulk emailing through the same API, but no campaign builder, segments or automation flows (pricing).
- Emails in your brand, no designer6 out of 10Drag-and-drop, HTML and rich-text builders with ready-made templates, which you still set up in your brand (pricing).
- Free plan5 out of 10A Free plan of 500 emails a month with 100 API requests a day, and a card on file (pricing).
- Price8 out of 10$35 a month for 20,000 emails on Starter, which covers 50,000, and $600 for a million on Starter (pricing).
- Developer tools9 out of 10Seven SDKs, an OpenAPI collection, SMTP relay, webhooks, inbound routing and testing features (pricing).
- Track record and support6 out of 10A 99.5% uptime SLA on its top plans, with dedicated IPs on Enterprise above 100,000 emails a week (pricing).
Rank 6Amazon SES
65.5 out of 100Total
- Priced by
- Emails sent
- Free plan
- None. New AWS customers get up to $200 in credits
- Entry price
- $0.10 per 1,000 emails, or $0.16 on Essentials
- Works from your AI assistant7 out of 10AWS's own managed MCP server runs SES API calls, so an agent can send and read sending data, but it connects with IAM credentials a person sets up, and new accounts start in the SES sandbox (AWS).
- Receipts and newsletters on one plan3 out of 10A sending service with contact lists and subscription management, but no campaign builder or automation flows (pricing).
- Emails in your brand, no designer2 out of 10Stored templates are HTML and text you write yourself. There is no visual editor and no brand setup (pricing).
- Free plan4 out of 10No standing free plan. New AWS customers get up to $200 in Free Tier credits that apply to SES (pricing).
- Price10 out of 10Metered at $0.16 per 1,000 on Essentials, so $3.20 for 20,000 emails and $160 for a million (pricing).
- Developer tools9 out of 10AWS SDKs in every major language, SMTP, event publishing, inbound receiving and a mailbox simulator for tests (docs).
- Track record and support9 out of 10Running at Amazon scale since 2011, with managed dedicated IPs, Virtual Deliverability Manager and tenant isolation (pricing).
Rank 7Postmark
64.5 out of 100Total
- Priced by
- Emails sent
- Free plan
- 100 emails a month, no expiry
- Entry plan
- $15 a month, 10,000 emails
- Works from your AI assistant6 out of 10Official MCP server with 24 tools, run locally with a server token a person creates first (Postmark).
- Receipts and newsletters on one plan4 out of 10Broadcast streams send bulk mail from the same account, but there is no campaign builder or flows (docs).
- Emails in your brand, no designer5 out of 10A library of ready-made transactional templates, which you still edit into your own brand (Postmark).
- Free plan4 out of 10A free Developer plan of 100 emails a month that never expires, for testing (pricing).
- Price8 out of 10$29.50 a month for 20,000 emails on Pro with overage, and $775 on Basic for the 1.5 million step (pricing).
- Developer tools9 out of 10Official libraries for Node.js and TypeScript, Python, Ruby, .NET, Java and PHP, SMTP, delivery and bounce webhooks, and inbound processing (docs).
- Track record and support9 out of 10A transactional specialist since 2010, with separate streams, managed dedicated IPs and 45-day retention (pricing).
Rank 8SMTP2GO
60 out of 100Total
- Priced by
- Emails sent
- Free plan
- 1,000 emails a month
- Entry plan
- $15 a month, 10,000 emails
- Works from your AI assistant7 out of 10A hosted MCP server whose execute-request tool can call any API endpoint, sends included, with an API key a person creates (docs).
- Receipts and newsletters on one plan2 out of 10A sending service for SMTP and API mail, with no campaign builder or automation flows (pricing).
- Emails in your brand, no designer4 out of 10Stored templates through its app and API, but the design is yours to build (docs).
- Free plan6 out of 101,000 emails a month, free for as long as you like, with no credit card (pricing).
- Price9 out of 10$27 a month for 20,000 emails on Starter with overage, and $520 for a million on Professional (pricing).
- Developer tools6 out of 10SMTP relay, REST API, webhooks, templates and testing tools. No SDKs or inbound email in its developer docs (docs).
- Track record and support7 out of 10A dedicated IP on Professional, subaccounts, and ticket, chat and phone support on paid plans (pricing).
How they compare
How each one scores
Scores out of 10, September 25, 2026| What we compared | Nitrosend | Resend | Bird | Mailtrap | MailerSend | SES | Postmark | SMTP2GO |
|---|---|---|---|---|---|---|---|---|
| Works from your AI assistant25 points | 9 out of 10 | 8 out of 10 | 8 out of 10 | 6 out of 10 | 8 out of 10 | 7 out of 10 | 6 out of 10 | 7 out of 10 |
| Receipts and newsletters on one plan15 points | 9 out of 10 | 7 out of 10 | 7 out of 10 | 7 out of 10 | 4 out of 10 | 3 out of 10 | 4 out of 10 | 2 out of 10 |
| Emails in your brand, no designer10 points | 9 out of 10 | 6 out of 10 | 4 out of 10 | 5 out of 10 | 6 out of 10 | 2 out of 10 | 5 out of 10 | 4 out of 10 |
| Free plan10 points | 7 out of 10 | 8 out of 10 | 6 out of 10 | 8 out of 10 | 5 out of 10 | 4 out of 10 | 4 out of 10 | 6 out of 10 |
| Price15 points | 8.5 out of 10 | 9 out of 10 | 10 out of 10 | 9 out of 10 | 8 out of 10 | 10 out of 10 | 8 out of 10 | 9 out of 10 |
| Developer tools15 points | 10 out of 10 | 9 out of 10 | 9 out of 10 | 10 out of 10 | 9 out of 10 | 9 out of 10 | 9 out of 10 | 6 out of 10 |
| Track record and support10 points | 4 out of 10 | 6 out of 10 | 7 out of 10 | 7 out of 10 | 6 out of 10 | 9 out of 10 | 9 out of 10 | 7 out of 10 |
| Total scoreout of 100 | 83.75 out of 100,1st | 77.5 out of 100,2nd | 76 out of 100,3rd | 74 out of 100,4th | 68.5 out of 100,5th | 65.5 out of 100,6th | 64.5 out of 100,7th | 60 out of 100,8th |
Here are the seven yes-or-no questions developers usually ask before they pick one of these services. A tick means the service does it, as described on its own pages today. A dash means the answer is not a clean yes or no.
8 services, side by side
Checked September 25, 2026QuestionNitrosendResendBirdMailtrapMailerSendSESPostmarkSMTP2GO
NitrosendResendBirdMailtrapMailerSendSESPostmarkSMTP2GOSend from the chatCan an agent send a transactional email without anyone opening the web app?Nitrosend: Yes.Resend: Yes.Bird: Yes.Mailtrap: Yes.MailerSend: Yes.SES: Not a yes or no.Postmark: Yes.SMTP2GO: Yes.
| Service | Answer |
|---|---|
| Nitrosend | Yes. Yes, through the MCP server. A single transactional email sends on the call; campaigns and flows stay drafts until approved. |
| Resend | Yes. Yes, once a person has created the account and verified a sending domain. |
| Bird | Yes. Yes, through the hosted MCP server once the workspace exists. Emailing customers needs a verified sending domain. |
| Mailtrap | Yes. Yes, once a person has signed up and handed the MCP server an API token. |
| MailerSend | Yes. Yes, once a person has signed up and authorized the MCP connection. |
| SES | Not a yes or no. Only through a sample or general AWS MCP server, with AWS credentials a person sets up. |
| Postmark | Yes. Yes, once a person has set up the account and handed the MCP server a server token. |
| SMTP2GO | Yes. Yes, through its MCP server once a person adds an API key. |
Hosted MCP serverCan a chat app connect over the web, with no local install?Nitrosend: Yes.Resend: Yes.Bird: Yes.Mailtrap: No.MailerSend: Yes.SES: No.Postmark: No.SMTP2GO: Yes.
| Service | Answer |
|---|---|
| Nitrosend | Yes. Yes. A remote server at api.nitrosend.com/mcp, with OAuth sign-in. |
| Resend | Yes. Yes. A remote server at mcp.resend.com/mcp, with OAuth sign-in. |
| Bird | Yes. Yes. mcp.bird.com, with OAuth sign-in. |
| Mailtrap | No. No. The official server runs locally through npx, or as a Claude Desktop extension. |
| MailerSend | Yes. Yes. Connect by URL and authorize access to the account. |
| SES | No. No hosted SES MCP server. |
| Postmark | No. No. The official server runs locally through npx with an API token. |
| SMTP2GO | Yes. Yes. A remote server at developers.smtp2go.com/mcp, with an API key header. |
Sign up with no personCan an agent create the account and send a first email with no DNS work?Nitrosend: Yes.Resend: No.Bird: Not a yes or no.Mailtrap: No.MailerSend: No.SES: No.Postmark: No.SMTP2GO: No.
| Service | Answer |
|---|---|
| Nitrosend | Yes. Yes. Signup is an API call, and each brand gets a ready sender on a Nitrosend subdomain. |
| Resend | No. No. Resend's own agent guide says a person must create the account. |
| Bird | Not a yes or no. An agent can sign itself up through the CLI or the API, but it must read the emailed sign-in code, and until a sending domain is verified it can send only to sandbox addresses and its own workspace members. |
| Mailtrap | No. No. Mailtrap's agent guide says a person signs up first. |
| MailerSend | No. No. A person signs up, with a card even on Free, and verifies a domain. |
| SES | No. No. A person opens the AWS account, verifies a domain and requests production access. |
| Postmark | No. No. A person signs up and confirms a sender signature or domain first. |
| SMTP2GO | No. No. A person signs up and verifies a sender domain first. |
Campaigns and flows in the same planDo newsletters and automations come with the transactional plan?Nitrosend: Yes.Resend: Not a yes or no.Bird: Not a yes or no.Mailtrap: Not a yes or no.MailerSend: No.SES: No.Postmark: Not a yes or no.SMTP2GO: No.
| Service | Answer |
|---|---|
| Nitrosend | Yes. Yes, on every plan including Free. |
| Resend | Not a yes or no. Broadcasts and automations are in the same account, on a separate marketing plan. |
| Bird | Not a yes or no. Broadcasts share the email allowance. Email automations are in early access, with a separate run allowance. |
| Mailtrap | Not a yes or no. In the same platform, on a separate Email Marketing plan priced by contacts. |
| MailerSend | No. No. Bulk emailing, but no campaign builder or flows. |
| SES | No. No. SES sends, and the campaigns and flows are yours to build. |
| Postmark | Not a yes or no. Broadcast streams handle bulk sends. There is no campaign builder or automation flows. |
| SMTP2GO | No. No. Sending only. |
Perpetual free planIs there a free plan that does not run out?Nitrosend: Yes.Resend: Yes.Bird: Yes.Mailtrap: Yes.MailerSend: Yes.SES: No.Postmark: Yes.SMTP2GO: Yes.
| Service | Answer |
|---|---|
| Nitrosend | Yes. Yes. 5,000 emails up front, then 500 a month. |
| Resend | Yes. Yes. 3,000 emails a month, 100 a day. |
| Bird | Yes. Yes. 1,000 emails a month, no time limit. |
| Mailtrap | Yes. Yes. 4,000 emails a month, 150 a day. |
| MailerSend | Yes. Yes. 500 emails a month. |
| SES | No. No. Up to $200 in AWS credits for new customers. |
| Postmark | Yes. Yes. 100 emails a month on the Developer plan, with no expiry. |
| SMTP2GO | Yes. Yes. 1,000 emails a month. |
Brand learned from your siteDoes it pick up your logo, colors, fonts and voice without a designer?Nitrosend: Yes.Resend: Not a yes or no.Bird: No.Mailtrap: No.MailerSend: No.SES: No.Postmark: No.SMTP2GO: No.
| Service | Answer |
|---|---|
| Nitrosend | Yes. Yes. Brand Kit scans your site, and AI Memory keeps house style. |
| Resend | Not a yes or no. Its AI features list URL and brand analysis, which its docs do not describe yet. |
| Bird | No. No. Templates and React Email, and you supply the design. |
| Mailtrap | No. No. Templates are built in its editor or in HTML. |
| MailerSend | No. No. Templates are built in its editors. |
| SES | No. No. Templates are HTML you write. |
| Postmark | No. No. A template library you edit into your own brand. |
| SMTP2GO | No. No. Templates are yours to build. |
Inbound emailCan it receive and parse email sent to your domain?Nitrosend: Yes.Resend: Yes.Bird: Yes.Mailtrap: Yes.MailerSend: Yes.SES: Yes.Postmark: Yes.SMTP2GO: No.
| Service | Answer |
|---|---|
| Nitrosend | Yes. Yes. An agent inbox on your own domain posts incoming mail to your webhook. |
| Resend | Yes. Yes, on every plan. |
| Bird | Yes. Yes. Inbound domains and relay webhooks. |
| Mailtrap | Yes. Yes. Mailtrap Inbound Email receives mail and exposes it over the API. |
| MailerSend | Yes. Yes, through inbound routing. |
| SES | Yes. Yes. SES receives mail through receipt rules and Mail Manager. |
| Postmark | Yes. Yes, with inbound processing on Pro and Platform. |
| SMTP2GO | No. No inbound email in its developer docs. |
Yes answersOut of the questions that have a yes or no for that service7 of 7 yes for Nitrosend4 of 5 yes for Resend4 of 5 yes for Bird3 of 6 yes for Mailtrap4 of 7 yes for MailerSend1 of 6 yes for SES3 of 6 yes for Postmark3 of 7 yes for SMTP2GO
At a glance
8 services, the same 7 tests, 100 points in all. In order: Nitrosend 83.75, Resend 77.5, Bird 76, Mailtrap 74, MailerSend 68.5, SES 65.5, Postmark 64.5, SMTP2GO 60. Nitrosend has the best score on Works from your AI assistant, Receipts and newsletters on one plan, Emails in your brand, no designer and Developer tools. Every price and feature was read on each company's own pages on September 25, 2026.
When another service is the better pick
Nitrosend does not win every test. Read these before you choose it.
- Pick Resend if you only send transactional email from application code. It scores 9 on developer tools, with official SDKs, an SMTP relay and inbound email on every plan, per Resend's pricing page. It also scores higher on free plan, 8 to 7, with 3,000 emails a month, and on track record.
- Pick Bird if the first $5 a month matters. It is $15 a month for 20,000 emails on Bird's Startup plan, against Nitrosend's $20, though $530 for a million against Nitrosend's $650. It matches Resend on developer tools, and it hosts its own MCP server at mcp.bird.com with OAuth sign-in.
- Pick Postmark if a receipt is arriving late or landing in spam. It scores 9 on track record, as a transactional specialist with separate message streams, managed dedicated IPs and 45-day retention, and 9 on developer tools, with official libraries for TypeScript, Python, Ruby, .NET, Java, PHP and Node.js, and inbound processing.
- Pick Mailtrap if you want a testing sandbox and production sending under one login. It scores 10 on developer tools, level with Nitrosend, with SDK guides for ten languages, SMTP, webhooks, inbound email, a CLI and a full email testing sandbox, and 8 on free plan, at 4,000 emails a month. The Mailtrap alternatives page ranks the services that replace it for sending.
- Pick Amazon SES if the lowest bill is all that matters. It is $3.20 for 20,000 emails and $160 for a million on the Essentials plan, which earns it a 10 on price. The catch is that SES is a sending service rather than a product, with no campaign builder or automation flows, and a person opens the AWS account, verifies a domain and requests production access before mail reaches anyone outside a sandbox.
- Pick MailerSend if a marketer edits the templates. It has drag-and-drop, HTML and rich-text builders, and seven SDKs, an SMTP relay and inbound routing behind them.
What each one costs in 2026
Every service here charges by emails sent, except Amazon SES, which is metered, at $0.10 per 1,000 a la carte or $0.16 per 1,000 on the Essentials plan that new accounts default to. Resend and Mailtrap also price their marketing sends by contacts.
What sending costs
List prices, USD, monthly, September 26, 2026| Service | 20,000 emails a month | 1,000,000 emails a month |
|---|---|---|
| Nitrosend (pricing page) | $20Starter, contacts unlimited | $650Scale, contacts unlimited, including overage |
| Resend (pricing page) | $20Pro, which covers 50,000 | $650Scale |
| Bird (pricing page) | $15Startup, which covers 50,000 | $530Growth |
| Mailtrap (pricing page) | $20Basic, which covers 50,000 | $750Enterprise, the 1,500,000 plan. Business stops at 750,000 for $450 |
| MailerSend (pricing page) | $35Starter, the first plan with 50 webhooks and 250 templates. Hobby with overage is $29.50 but has 1 webhook and 10 templates | $600Starter |
| SES (pricing page) | $3.20Lowest. Essentials, the default for a new account, or $2 a la carte. Charged per email | $160Lowest. Essentials, the default for a new account, or $100 a la carte. Charged per email |
| Postmark (pricing page) | $29.50Pro, 10,000 included and $1.30 per 1,000 after. Basic is $33 | $775Basic, the 1,500,000 plan. Pro is $852.50 |
| SMTP2GO (pricing page) | $27Starter, 10,000 included and $1.20 per 1,000 after | $520Professional |
At 20,000 emails a month, Nitrosend is $20. Resend and Mailtrap are also $20, SMTP2GO is $27, Postmark $29.50 and MailerSend $35. Bird at $15 is $5 less, and Amazon SES is $3.20.
At a million emails a month, Nitrosend is $650. SMTP2GO is $520, Bird $530, MailerSend $600, Resend $650, Mailtrap $750 and Postmark $775. With Amazon SES the campaign builder, the flows and the email design are yours to build. Brevo, a marketing suite that also sends transactional email, is scored on email marketing tests on the Brevo alternatives page instead.
The bigger difference is what the $20 buys. Nitrosend's own developer page puts it plainly: most email APIs stop at "send a message", and Nitrosend provides the entire stack through the same key, lists, segments, automated flows, brands, templates and deliverability, alongside a single-call transactional send. Mailgun's own pricing FAQ says "There's no send button in Mailgun", so if you would otherwise buy a second product for campaigns, add the two bills together before you compare.
How we scored
Every service gets a score out of 10 on the same seven tests. Each test is worth a set number of points, 100 in all. Working from your AI assistant is worth the most, 25 points, because that is where email is heading. Price, developer tools and track record, where the older services are strongest, share 40 points, so a service that is better there gets full credit for it.
Each test is a question with one answer per service, checked against the service's own pages on September 25, 2026. A 10 means it does the job fully on its normal plans. A 5 means it does part of it, or only on a higher plan or in a second product.
Works from your AI assistant, 25 points. Can an agent inside Claude, ChatGPT, Cursor or Codex go from nothing to a delivered transactional email, and then read back what happened to it, with no person opening the web app along the way? Scored on the first-party MCP server and what its tools cover, a CLI that works in a non-interactive runner, account and sender setup over the API, and listings in the chat apps people already work in. Scored on one written rule for every vendor: a first-party server the vendor runs and that can send counts fully; a third-party wrapper (Zapier, Composio, Kanopi, community servers) counts for less; a server that only drafts or reads counts for less than one that sends.
Receipts and newsletters on one plan, 15 points. Can receipts and password resets, and the newsletters and automated flows that follow them, go out from one account, on one bill, through one API, with the two streams kept apart?
Emails in your brand, no designer, 10 points. Does the product produce the receipt, reset and welcome emails in your brand's own logo, colors, fonts and voice, or does a developer have to write or buy the HTML template first?
Free plan, 10 points. How far can a developer get on the free plan before paying: the monthly volume, the daily ceiling, any one-off starter allowance, and whether the plan is perpetual or a trial that ends.
Price, 15 points. What does sending cost at 20,000 emails a month, where most teams start, and at 1,000,000, where a busy product ends up? Scored on list prices in US dollars, paid monthly, at the cheapest plan that covers the volume. Every ranking on this site uses the same fixed scale. At 20,000 emails, $20 or less scores 10, then $25 scores 9, $32 scores 8, $40 scores 7, $50 scores 6, $70 scores 5, $100 scores 4 and $140 scores 3. At 1,000,000, $500 or less scores 10, then $625, $800, $1,000, $1,250, $1,750, $2,500 and $3,500 step down the same way. Anything dearer, or a price given only by quote, scores 2. The score is the average of the two.
Developer tools, 15 points. How complete is what a developer builds on: a REST API with an OpenAPI spec, official SDKs across languages, a CLI, an SMTP relay, documented delivery-event webhooks, idempotent sends, a test or sandbox mode, inbound email handling, and how deep the reference docs go?
Track record and support, 10 points. How long has it run transactional sending at scale, which deliverability controls can you own (dedicated IPs, suppression, separate streams, a published uptime SLA), and what support comes with the plan?
One thing is not scored: inbox placement. No two of these services publish a comparable deliverability number, so a score there would be a guess dressed up as a measurement.
SendGrid, Mailgun and Postmark are reliable, and their uptime is not in question. They were built for application code that already knows what to send, and Mailgun's agent path shows it. A new Mailgun account comes with a sandbox domain that can only send to up to five authorized recipients, so an agent can send itself a test but cannot reach a real customer until a person adds and verifies a custom domain. Mailgun's MCP server runs locally on your machine with an API key in its settings, and Mailgun does not offer a hosted version. The gap between an agent that can send a test and an agent that can finish the job is what the 25-point test measures. In Nitrosend, each brand prepares a reserved sender when it is ready to send, and that sender's capacity grows with its own clean delivered volume, as the email providers documentation describes.
When to keep Mailgun and when to replace it
Keep it for what it is good at, which is the receiving side. Inbound routes, parsing rules, address validation and a solid SMTP relay are the real Mailgun product. If your application takes replies apart and does something with them, that is a hard capability to move.
Replace it, or more usually add to it, when the problem is above the pipe.
Visibility. Log retention on Mailgun's pricing page runs one day on Free and Basic, five days on Foundation and 30 days on Scale, checked October 1, 2026. One day of logs is not enough to investigate a deliverability problem you first hear about on Monday morning, so teams on the lower plans keep their own copy of every event, and Mailgun's own docs show two places that copy leaks. Its webhook retry schedule covers every event other than the delivery notification, so if your endpoint is down when a message is delivered, that event is not sent again. And its event polling guide warns that events can reach storage out of order, so a simple poll misses some unless it only trusts pages older than a threshold, half an hour in Mailgun's example.
Scope. Mailgun's pricing FAQ says it in one line: "There's no send button in Mailgun." The moment somebody wants a three-step onboarding sequence, you either build the state machine in your own application or buy a second tool. Usually a developer owns transactional and a marketer owns campaigns, and neither one sees the other half.
Price shape. The free tier is 100 emails a day and the entry plan is $15 a month, but the number that decides your bill is the overage, which starts at $1.80 per 1,000 emails on Basic, checked October 1, 2026, with address validation billed separately. Dedicated IPs are available from 50,000 emails a month and included from 100,000, and extra IPs are $59 per IP per month, all on the same pricing page.
Ownership. Sinch bought Pathwire, the company behind Mailgun and Mailjet, in 2021. If you chose Mailgun as the independent option, it has not been that for a while.
Can I keep Mailgun and add campaigns on top?
Yes, on a paid Nitrosend plan, and for most teams that is the right shape. Your sending reputation lives on the domain and the IPs you have been warming through Mailgun, and moving that is the riskiest part of any migration. Nitrosend's Mailgun integration takes your private API key and your Mailgun sending domain, and from then on Nitrosend handles composition, audiences, automation, tracking and suppression while your Mailgun account carries the mail, transactional sends included. Three details catch people out, all on that integration page. Nitrosend connects to Mailgun's US API endpoint, so an EU-hosted Mailgun account is not supported today. An agent can store the credentials over MCP, but that call does not test them, so run the connection test from the dashboard or the REST API before you rely on it. And rotating the Mailgun key later resets the integration's verified domains to pending until you verify them again. If you later want to move the sending as well, you change one setting and warm the new path. The mechanics are on the bring-your-own sending keys page.
Will I lose my inbound routes if I move?
Only if you move them. Inbound routing and parsing is Mailgun's strongest feature, and it hangs on different DNS records from sending. Mailgun receives mail for a domain through the MX records that point at mxa.mailgun.org and mxb.mailgun.org, while sending rests on SPF and DKIM. So the subdomain that takes replies can keep its MX records on Mailgun while the sending records move, and nothing about your routes changes. Mailgun's Free plan includes one inbound route and Basic five, with full access from Foundation, so check which plan your routes need before you downgrade the account you keep.
Of the services here, Resend, Bird, Mailtrap, Postmark, Amazon SES and MailerSend all accept inbound email, and SMTP2GO's developer docs do not list it. Nitrosend's Agent Inbox posts incoming mail to your webhook, one address at a time. If your application receives mail at addresses you cannot set up in advance, keep Mailgun for that leg and move the rest. Running inbound on one provider and outbound on another is normal, and much less disruptive than rebuilding a parser you already trust. How webhooks work covers the event side of that split.
George Hartley, Nitrosend's co-founder, is candid that Nitrosend's own bet on agent inboxes is early. On The Breakout CEO in August 2026 he said of them: "we're not getting much user pull right now. There's no one who's building a 10 person startup saying, Hey, I need 10 agent inboxes, no one's asking us for that. But we've just shipped it because I kind of think that it will be useful. Um, but maybe it won't". So if parsed replies to your own endpoint run your product today, the advice above stands: keep Mailgun on that leg.
How to move off Mailgun without losing deliverability
Swapping the API takes an afternoon. The reputation takes weeks.
- Export your suppression list first. Take your contacts and recent sending history too. Bounces and complaints are the part you cannot rebuild.
- Authenticate the new sender. Keep both senders in one SPF record for the overlap. The email authentication page has the records, including where
p=quarantinebelongs in your DMARC policy. - Move one message type first. Pick a low-risk transactional stream rather than a percentage of everything.
- Split promotional and transactional sending across subdomains. A large campaign then cannot damage receipt delivery.
- Warm the new path. Ramp up rather than switching in one send. How to warm up an email domain has the schedule.
- Test placement before the volume moves. Run an inbox placement test, then watch bounce and complaint rates daily for a month.
For the sending path itself, the email API hub covers what happens between your request and the recipient's mail server, and transactional email, in practice covers the messages on it.
Mailgun alternatives FAQ
Nitrosend, with the top score in this review, 83.75 out of 100. It adds the campaigns, automated flows and single view of every email that Mailgun does not have, on one plan from $20 a month, and your AI assistant can sign up and send from it without a person opening a dashboard. On a paid plan it can also keep sending through a US-hosted Mailgun account. Pick Postmark if the problem is late receipts, and Amazon SES if unit cost is the whole decision.
It depends on the overage rather than the plan. The free tier is 100 emails a day and Basic starts at $15 a month, but overage begins at $1.80 per 1,000 emails and address validation is billed separately, per Mailgun's pricing page, checked October 1, 2026. At high volume that is many times the Amazon SES a la carte rate of $0.10 per 1,000, which is why heavy senders drift to AWS.
Nitrosend, which scores 9 out of 10 on working from your AI assistant. It has an official MCP server, account signup over the API and a ready-made sender, so an agent in Claude, ChatGPT, Cursor or Codex sends with no dashboard. Mailgun's own MCP server runs locally with an API key, and a new account's sandbox domain only reaches up to five authorized recipients. Resend, Bird and MailerSend score 8, with hosted MCP servers and OAuth sign-in, but a human must create the Resend account, an agent that signs up to Bird from its CLI still needs someone to read the emailed verification code, and MailerSend's connects only after a person has signed up. Mailtrap, Postmark and SMTP2GO also have MCP servers that need a token or sign-up from a person. Amazon SES has no SES-specific MCP product, but AWS's own managed AWS MCP Server runs SES API calls with IAM credentials a person sets up, which scores it 7.
Yes, on a paid plan and with a US-hosted Mailgun account. Add your private Mailgun API key and sending domain as the sending integration and your mail leaves through your own Mailgun account, keeping the reputation you have built, while campaigns, flows, contacts and reporting live in one place. EU-hosted Mailgun accounts are not supported today, per the Mailgun integration docs.
For mail to addresses you set up, yes. Nitrosend has an Agent Inbox that posts incoming mail to your webhook, and an AI agent can read and reply over MCP, with SPF, DKIM and DMARC results visible per message. Mail it quarantines as spam, a virus or a blocked sender is not posted. It has no route rules that match patterns across a domain. If routes carry weight in your product, keep the MX records for that subdomain on Mailgun and move only the sending.
Sinch, the Swedish communications company, which bought Pathwire, the parent of Mailgun and Mailjet, in 2021. If you are comparing options partly on independence, the same question applies to SendGrid under Twilio and Postmark under ActiveCampaign. The SendGrid alternatives page covers the Twilio side.
Add Nitrosend's MCP server at api.nitrosend.com/mcp to Claude, or to ChatGPT, Cursor or Codex, and sign in with OAuth. Then ask for the email in plain words. A transactional message such as a receipt goes out on the call, and a campaign or flow is built as a draft that waits until it is approved. If you want Mailgun to keep carrying the mail while you switch, connect your Mailgun key on a paid plan and Nitrosend sends through it. The MCP documentation lists the tools.
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