The shortlist is Postmark if a receipt is arriving late or landing in spam, Nitrosend if the missing piece is campaigns, flows and one view of every email your product sends, and Amazon SES if the bill at volume is the whole problem. We send some of our own marketing email through Mailgun, on a separate domain, so nothing here is a hit piece on a provider we run on.
The short version
If a receipt is arriving late or landing in spam, Postmark is the straight replacement, and it is the one to trial first. If the bill is the problem at volume, Amazon SES is the cheapest transport there is and you pay for it in engineering time. If the API and the docs are the problem, Resend is tidier than anything else here. If you want a nicer dashboard and drag-and-drop templates without leaving the transactional world, MailerSend is built by the MailerLite team for exactly that, and Brevo adds campaigns and SMS at the budget end. If you want a plain relay with human support, SMTP2GO. If you want a testing sandbox alongside production sending, Mailtrap.
And if what you are missing is campaigns, flows and one view of every email your product sends, Nitrosend does that on top of your existing Mailgun key. We get paid whether you keep Mailgun or not, which is exactly why the rest of this page can be specific.
When to keep Mailgun and when to replace it
Keep it for what it is genuinely good at, which is the receiving side. Inbound routes, parsing rules, address validation and a solid SMTP relay are the real Mailgun product, and they are better than the marketing pages make them sound. If your application takes replies apart and does something with them, that is a hard capability to move, and no page on the internet should talk you out of it casually.
Replace it, or more usually add to it, when the problem is above the pipe.
The first friction is visibility, and it is structural rather than a matter of taste. Log retention on Mailgun's own pricing page runs one day on Free and Basic, five days on Foundation and 30 days on Scale, checked 7 September 2026. One day of logs is not enough to investigate a deliverability problem you first hear about on Monday morning.
The second is scope. Mailgun has basic marketing sends and no automation flows, checked 7 September 2026. So the moment somebody wants a three-step onboarding sequence, you either build the state machine in your own application or you buy a second tool. In a startup that split is usually a developer who owns transactional and a marketing person who owns campaigns, and neither one can see the other half. Growth does not know what the product sends. The developer never sees the newsletter.
The third is 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 7 September 2026, with address validation billed separately again. Amazon SES publishes $0.10 per 1,000 a la carte and $0.16 on its Essentials plan, checked the same day, which is why high-volume senders keep drifting to AWS.
A dedicated IP follows the same ladder. It is not included on Free or Basic, and extra IPs are $59 per IP per month, checked 7 September 2026. So the tiers priced like bare infrastructure are exactly the ones without the logs or the IP a real sending programme needs.
The fourth is ownership. Sinch owns Mailgun. Not a scandal, but if you chose Mailgun as the independent option, it has not been that for a while. Worth remembering too that Mailgun cut its free tier from 10,000 to 625 emails a month effective 1 March 2020, a change that drew 422 points and 255 comments on Hacker News at the time. Trustpilot rates Mailgun 4.1 out of 5 across 1,526 reviews, checked 7 September 2026, with account suspension and support access the recurring negative theme.
How they compare
Scores are out of 10 against criteria whose weights add to 100. They are published in full at the bottom of this page, so you can disagree with a weight and re-rank the table yourself.
Prices come from each vendor's own pricing page, read on 7 September 2026. Where a cell in the table is blank, that vendor publishes the figure only behind a volume slider, so it was not readable rather than absent.
We make Nitrosend. It moved to first on this list in September 2026, and the criterion that moved it is the founding-team one, on which it scores highest of the eight platforms here. That criterion is scored on the same four questions for every vendor, the workings are published at the bottom of this page, and if you weight it at zero the platform at the top of this table is Postmark.
Mailgun alternatives compared
Checked| Platform | Rank | Best for | Pricing model | Free tier | From | At 100k emails/mo | Score |
|---|---|---|---|---|---|---|---|
| Nitrosend Agent-native | 1 | The layer above | per send | 8,000 emails to start, then 500 a month | $20/mo | $100/mo (Ultra) | 9.3 |
| Resend | 2 | Developer experience | per send | 3,000 emails a month, 100 a day | $20/mo | $90/mo (Scale) | 8.2 |
| Postmark | 3 | Transactional delivery | per send | Developer trial only | $15/mo | n/a | 8.0 |
| Brevo | 4 | Budget all in one | per send | 300 emails a day, unlimited contacts | $9/mo | n/a | 7.3 |
| Amazon SES | 5 | Lowest unit cost | usage | 3,000 message charges a month for the first 12 months, for new senders | $0.10 per 1,000 | n/a | 7.2 |
| MailerSend | 6 | Friendlier dashboard | per send | 500 emails a month | $7/mo | $68/mo (Starter) | 6.9 |
| Mailtrap | 7 | Testing plus sending | per send | 4,000 emails a month, capped at 150 emails a day | $15/mo | $30/mo (Basic) | 6.9 |
| SMTP2GO | 8 | Predictable relay | per send | 1,000 emails a month | $10/mo | $75/mo (Professional) | 6.7 |
1. Nitrosend
Best for: teams whose transactional email works and who cannot see any of it.
The reason to look at us is the layer, not the pipe. One account holds transactional sending, campaigns, flows, contacts and analytics, so there is a single view of every email your product sends, the receipts included. That is the thing a developer and a growth person cannot get today when one owns Mailgun and the other owns a marketing tool.
The transactional path stays deliberately light. A single transactional send writes one send record and skips the flow machinery entirely, because flows are far too heavyweight for a password reset. Marketing and transactional streams stay separated internally so a campaign cannot crowd out a receipt. The MCP server exposes 28 nitro_* tools, so Claude, Codex or Cursor can build the flow, run the import or read back the send. Full API, MCP and CLI access is on every plan, including the free one, which is 8,000 emails to start then 500 a month with 100 / 500 / 5,000 recipients per rolling 24 hours for Free Probation / Standard / Trusted. Paid starts at $20 a month for 20,000 emails, checked 7 September 2026, and contacts are unlimited on every tier.
Keeping Mailgun is a supported answer. Add your Mailgun key as the sending integration and your mail keeps leaving through the account you have already warmed, which needs a verified domain and a completed brand setup on our side and nothing on yours. The Nitrosend and Mailgun comparison has the numbers side by side.
Where it loses: no inbound email parsing over REST. Mailgun routes are a real capability we do not match, and our Agent Inbox is read and replied to over MCP and the dashboard rather than POSTed to your endpoint. Our unit cost at high volume is above SES and SMTP2GO. And we do not do cold outreach.
- Nitrosend at a glance
- Verified on the vendor's own pages
- Best for
- teams whose transactional email works and who cannot see any of it
- Pricing model
- per send
- Free tier
- 8,000 emails to start, then 500 a month
- Entry paid plan
- $20/mo (20,000 emails a month, 5 brands, 3 domains, up to 1,000 / 10,000 / 100,000 recipients per rolling 24 hours for Pro Probation / Standard / Trusted)
- At 100,000 emails a month
- $100/mo (Ultra)
- Transactional API
- yes
- Marketing campaigns
- yes
- Automation flows
- yes
- SMS
- yes
- First-party MCP server
- yes
- Inbound email parsing
- no
- Support
- Help center: docs.nitrosend.com
- Developer docs
- API documentation: docs.nitrosend.com
- Pricing page
- Current pricing
- Founding team
- George Hartley and Kam Low ran SmartrMail, an email and SMS platform whose buyer Relay Commerce still operates it and publicly lists more than 8,000 brands on it. Kam Low's open-source record runs from 2009 under the Sourcey organisation. All three founders are in post.
- Founding team score
- 9.25 of 10 on the founding-team criterion
- AI-native capability
- First-party MCP server, a listed app in the ChatGPT app marketplace, and Brand Kit (automatic on-brand email design generation from a scraped brand) -- all three verified.
- AI-native score
- 10 of 10 on the AI-native criterion
- Limitations
- No inbound email parsing over REST, so Mailgun routes do not port
- Unit cost at high volume is above SES and SMTP2GO
- No cold outreach
- Facts checked
2. Resend
Best for: a modern codebase where the email should read like the rest of the application.
The tidiest API surface in this category, React Email templates, and a free tier of 3,000 emails a month with a 100 a day cap. Broadcasts and automations have been added on top, and there is a first-party MCP server, which is rare here. If Mailgun's API and documentation were the friction, this is the obvious move.
The trade is that the marketing layer is young next to a real ESP, several things are add-ons with their own monthly fees (extra domains, dedicated IPs, single sign-on), and it runs on AWS underneath, so it is not a way to avoid SES.
- Resend at a glance
- Verified on the vendor's own pages
- Best for
- a modern codebase where email should read like the rest of the application
- Pricing model
- per send
- Free tier
- 3,000 emails a month, 100 a day
- Entry paid plan
- $20/mo (50,000 emails a month, extra emails $0.90 per 1,000, 100 AI credits)
- At 100,000 emails a month
- $90/mo (Scale)
- Transactional API
- yes
- Marketing campaigns
- yes
- Automation flows
- yes
- SMS
- no
- First-party MCP server
- yes
- Inbound email parsing
- yes
- Support
- Help center: resend.com/help
- Developer docs
- API documentation: resend.com/docs
- Status page
- System status: resend-status.com
- Pricing page
- Current pricing: resend.com/pricing
- Founding team
- Zeno Rocha has the strongest independently checkable engineering record in this set, with clipboard.js at 34,117 GitHub stars and the Dracula theme at 23,577. No prior email platform. All three co-founders are in post.
- Founding team score
- 8.50 of 10 on the founding-team criterion
- AI-native capability
- Has a first-party MCP server for agent-callable access, but no verified on-brand automatic design generation (Brand Kit-style) or ChatGPT app marketplace listing.
- AI-native score
- 4 of 10 on the AI-native criterion
- Limitations
- The marketing layer is young next to a full ESP
- Extra domains, dedicated IPs and single sign-on are add-ons
- Runs on AWS underneath
- Facts checked
3. Postmark
Best for: transactional mail where the receipt has to arrive now.
Postmark is the reference point for transactional delivery. Message streams keep broadcasts away from receipts so one does not poison the other, the activity log shows you the actual delivery conversation rather than a status word, and inbound parsing is there if you need to keep that leg. If you are leaving Mailgun because of latency, placement or because you cannot tell what happened, this is the first thing to trial.
The trade is price and scope. There is no free plan, only a developer trial, and it is $15 a month for 10,000 emails, checked 7 September 2026, which is expensive per thousand once volume climbs. There are no marketing campaigns and no automation flows at all. And Postmark is owned by ActiveCampaign, so the independent-vendor question follows you here too.
- Postmark at a glance
- Verified on the vendor's own pages
- Best for
- transactional mail where the receipt has to arrive now
- Pricing model
- per send
- Free tier
- Developer trial only
- Entry paid plan
- $15/mo (10,000 emails a month)
- Transactional API
- yes
- Marketing campaigns
- no
- Automation flows
- no
- SMS
- no
- Inbound email parsing
- yes
- Owner
- ActiveCampaign
- Support
- Help center: postmarkapp.com/support
- Developer docs
- API documentation: postmarkapp.com/developer
- Status page
- System status: status.postmarkapp.com
- Pricing page
- Current pricing: postmarkapp.com/pricing
- Founding team
- Chris and Natalie Nagele ran Postmark inside Wildbit for thirteen years with a strong developer reputation. ActiveCampaign acquired it on 3 May 2022 and neither founder remains.
- Founding team score
- 5.50 of 10 on the founding-team criterion
- AI-native capability
- Not independently verified for MCP/agent access in this comparison; no on-brand automatic design generation or ChatGPT app marketplace listing found in a light spot-check.
- AI-native score
- 2 of 10 on the AI-native criterion
- Limitations
- No free plan, only a developer trial
- No marketing campaigns or automation flows
- Owned by ActiveCampaign
- Facts checked
4. Amazon SES
Best for: volume where the per-thousand rate is the only number that matters.
AWS publishes two structures on one page: a la carte at $0.10 per 1,000 emails sent, plus data and receiving charges, and three named plans starting at $0.16 per 1,000 up to 10 million a month, both checked 7 September 2026. Either way nothing else here is close. Inbound receiving is there. It scales without a sales call.
You are buying a pipe and building the rest. No campaigns, no automation, no template editor worth the name, thin analytics, support as a separate AWS contract, and an approval step before production access. We run our own managed sending on SES, so I will be blunt about the hidden cost: suppression lists, bounce and complaint handling, configuration sets and reputation monitoring are all yours. If you are leaving Mailgun because you cannot see anything, SES is a step backwards on exactly that axis.
- Amazon SES at a glance
- Verified on the vendor's own pages
- Best for
- volume where the per-thousand rate is the only number that matters
- Pricing model
- usage
- Free tier
- 3,000 message charges a month for the first 12 months, for new senders
- Entry paid plan
- $0.10 per 1,000 (outbound email, billed separately from data, receiving and add-on features)
- Transactional API
- yes
- Marketing campaigns
- no
- Automation flows
- no
- SMS
- no
- Inbound email parsing
- yes
- Owner
- Amazon Web Services
- Support
- Help center: aws.amazon.com/contact-us
- Developer docs
- API documentation: docs.aws.amazon.com/ses
- Status page
- System status: health.aws.amazon.com/health/status
- Pricing page
- Current pricing: aws.amazon.com/ses/pricing
- Founding team
- Amazon SES has no founding team. It has been an Amazon Web Services first-party service since 2011 and names no individual anywhere. The credibility here is institutional, which is a different thing from a founding team and is scored as such.
- Founding team score
- 2.50 of 10 on the founding-team criterion
- AI-native capability
- Not independently verified for MCP/agent access in this comparison; no on-brand automatic design generation or ChatGPT app marketplace listing found in a light spot-check.
- AI-native score
- 2 of 10 on the AI-native criterion
- Limitations
- No campaigns, automation or usable template editor
- Suppression, bounce handling and reputation monitoring are yours to build
- A step backwards on visibility, which is the usual reason for leaving Mailgun
- Facts checked
5. Brevo
Best for: small teams that want campaigns, SMS and a transactional API on one cheap bill.
Priced on emails sent rather than contacts held, with a free tier of 300 emails a day and paid from $9 a month, checked 7 September 2026. For a small business that needs a newsletter more than it needs routing rules, this is the pragmatic all-in-one.
Two cautions. Enforcement is fast, and a suspended account takes its reporting with it, which is a bad trade if visibility was your reason for moving. The Brevo alternatives page has the detail. And the developer experience is well behind everything above it on this list.
- Brevo at a glance
- Verified on the vendor's own pages
- Best for
- small businesses that need a newsletter more than they need routing rules
- Pricing model
- per send
- Free tier
- 300 emails a day, unlimited contacts
- Entry paid plan
- $9/mo (from 5,000 emails a month)
- Transactional API
- yes
- Marketing campaigns
- yes
- Automation flows
- yes
- SMS
- yes
- First-party MCP server
- yes
- Inbound email parsing
- yes
- Owner
- Brevo (formerly Sendinblue, independent)
- Support
- Help center: help.brevo.com
- Developer docs
- API documentation: developers.brevo.com
- Status page
- System status: status.brevo.com
- Pricing page
- Current pricing: brevo.com/pricing
- Founding team
- Armand Thiberge founded Brevo in 2012 and is still chief executive, though ownership is now heavily institutional after the December 2025 round.
- Founding team score
- 5.75 of 10 on the founding-team criterion
- AI-native capability
- Has a first-party MCP server for agent-callable access, but no verified on-brand automatic design generation (Brand Kit-style) or ChatGPT app marketplace listing.
- AI-native score
- 4 of 10 on the AI-native criterion
- Limitations
- Enforcement is fast and a suspended account takes its reporting with it
- Developer experience is well behind the rest of this list
- Automation depth is shallow on the entry plans
- Facts checked
6. MailerSend
Best for: teams that want transactional sending with a dashboard a non-developer can use.
Built by the MailerLite team, which shows: drag-and-drop templates, a clean interface, built-in verification and an inbound route if you need one. It is the natural landing spot for a small team that finds Mailgun's console cold and does not need SES economics.
The pricing is slider-driven, so read the table carefully. Free is 500 emails a month with a credit card on file, Hobby is $7 a month for 5,000 emails, and at 100,000 emails a month Starter is $68, all checked 7 September 2026. Extra usage above the allowance is $1.30 per 1,000 on Starter. That is cheaper than Mailgun's overage at every step, which is the real argument for it.
- MailerSend at a glance
- Verified on the vendor's own pages
- Best for
- small teams that find the Mailgun console cold and do not need SES economics
- Pricing model
- per send
- Free tier
- 500 emails a month
- Entry paid plan
- $7/mo (5,000 emails a month, 5 seats, 1 domain, 10 templates, 1,000 daily API requests; extra usage $1.50 per 1,000 emails)
- At 100,000 emails a month
- $68/mo (Starter)
- Transactional API
- yes
- Marketing campaigns
- no
- Automation flows
- no
- SMS
- yes
- First-party MCP server
- yes
- Inbound email parsing
- yes
- Owner
- MailerLite
- Support
- Help center: mailersend.com/help
- Developer docs
- API documentation: developers.mailersend.com
- Status page
- System status: status.mailersend.com
- Pricing page
- Current pricing: mailersend.com/pricing
- Founding team
- No founder is named anywhere. MailerSend states it is part of the MailerLite team, which Vercom S.A. owns.
- Founding team score
- 2.50 of 10 on the founding-team criterion
- AI-native capability
- Not independently assessed for MCP/agent access, on-brand design generation, or ChatGPT marketplace listing in this comparison.
- AI-native score
- 2 of 10 on the AI-native criterion
- Limitations
- The free plan is 500 emails a month and asks for a credit card
- No marketing campaigns or automation flows
- Owned by MailerLite, which repriced its own platform in 2026
- Facts checked
7. Mailtrap
Best for: teams that want staging capture and production sending from one vendor.
Mailtrap began as an email testing tool and grew a sending service, and the testing half is still the reason to choose it. Catching staging mail in a fake inbox while production sends through the same account removes a whole category of accident. There is a free tier and the first paid step is $15 a month, checked 7 September 2026.
As a production transport it is smaller and younger than everything above, with no campaign or automation layer. If testing is the real problem, the Mailtrap alternatives page compares that field properly.
- Mailtrap at a glance
- Verified on the vendor's own pages
- Best for
- teams that want their test inbox and their live transport in the same account
- Pricing model
- per send
- Free tier
- 4,000 emails a month, capped at 150 emails a day
- Entry paid plan
- $15/mo (10,000 emails a month, 3 users, 5 domains, 5 days of email logs, no dedicated IP)
- At 100,000 emails a month
- $30/mo (Basic)
- Transactional API
- yes
- Marketing campaigns
- no
- Automation flows
- no
- SMS
- no
- Inbound email parsing
- yes
- Owner
- Railsware
- Support
- Help center: help.mailtrap.io
- Developer docs
- API documentation: api-docs.mailtrap.io
- Pricing page
- Current pricing: mailtrap.io/pricing
- Founding team
- Mailtrap was built inside Railsware, a product studio operating since 2007, and no individual founder of Mailtrap itself is named anywhere. Railsware still owns and runs it.
- Founding team score
- 5.25 of 10 on the founding-team criterion
- AI-native capability
- Not independently assessed for MCP/agent access, on-brand design generation, or ChatGPT marketplace listing in this comparison.
- AI-native score
- 2 of 10 on the AI-native criterion
- Limitations
- Smaller and younger as a production transport
- No campaign or automation layer
- The sending ladder is not the reason to buy it
- Facts checked
8. SMTP2GO
Best for: a predictable relay with support that answers.
A flat ladder with no slider games, 1,000 emails a month free, $10 a month for 10,000 and $75 a month for 100,000, checked 7 September 2026, and 24/7 human support that is the most consistently praised part of the product. If Mailgun's overage rate is what stings, this is the calmest replacement.
No marketing campaigns, no automation, no inbound parsing. It replaces the sending half of Mailgun and makes no claim on the routing half.
- SMTP2GO at a glance
- Verified on the vendor's own pages
- Best for
- teams stung by overage rates who want a plain ladder
- Pricing model
- per send
- Free tier
- 1,000 emails a month
- Entry paid plan
- $10/mo (10,000 emails a month, $100 a year, extra emails $1 per 1,000)
- At 100,000 emails a month
- $75/mo (Professional)
- Transactional API
- yes
- Marketing campaigns
- no
- Automation flows
- no
- SMS
- no
- Inbound email parsing
- no
- Support
- Help center: support.smtp2go.com
- Developer docs
- API documentation: apidoc.smtp2go.com
- Status page
- System status: status.smtp2go.com
- Pricing page
- Current pricing: smtp2go.com/pricing
- Founding team
- SMTP2GO has operated since 2006 and handles email for more than 40,000 paying customers, but names no founder, no chief executive and no engineering leader on any page.
- Founding team score
- 2.75 of 10 on the founding-team criterion
- AI-native capability
- Not independently assessed for MCP/agent access, on-brand design generation, or ChatGPT marketplace listing in this comparison.
- AI-native score
- 2 of 10 on the AI-native criterion
- Limitations
- No marketing campaigns or automation
- No inbound parsing, so Mailgun routes have nowhere to go
- Nothing for an AI agent to drive
- Facts checked
Can I keep Mailgun and add campaigns on top?
Yes, 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. Connect your Mailgun key to Nitrosend as the sending integration, import your contacts, and build campaigns and flows against the transport you already trust. Transactional sends keep going out exactly as they do now, the analytics land in one place, and if you later want to move the transport as well you change one setting and warm the new path deliberately. The mechanics are on the bring-your-own sending keys page.
What is the cheapest Mailgun alternative at 100,000 emails a month?
Amazon SES on unit cost, at $0.10 per 1,000 a la carte or $0.16 on Essentials, which is $10 to $16 of sending at that volume. On published plan prices, Mailtrap is $30 a month on Basic, MailerSend is $68 on Starter, SMTP2GO is $75 and Resend is $90 on Scale, all checked 7 September 2026, and all four include a product around the sending that SES does not. Mailgun's own included volumes are set by a slider, so compare your quote at your volume rather than the entry price. Then add the engineering hours, because at 100,000 emails a month one lost engineer week wipes out every dollar SES saved you.
Will I lose my inbound routes if I move?
Probably, and this is the honest hard stop on this page. Inbound routing and parsing is Mailgun's strongest feature and the alternatives are uneven: Postmark, Amazon SES and MailerSend all do inbound, SMTP2GO does not, and Nitrosend has no inbound parsing over REST at all. If your application depends on parsed replies POSTed to your own endpoint, keep Mailgun for that leg and move the rest. Running the inbound route on one provider and outbound on another is normal, and it is much less disruptive than rebuilding a parser you already trust.
How to move off Mailgun without losing deliverability
- Export your suppression list, your contacts and your recent sending history before you change anything. Bounces and complaints are the part you cannot reconstruct.
- Authenticate the new sender on your domain and 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, not a percentage of everything. A low-risk transactional stream is the right test.
- Split promotional and transactional sending across subdomains so a large campaign cannot damage receipt delivery. That reputation isolation is worth more than any feature on this page.
- Warm the new path rather than switching in one send. How to warm up an email domain has the ramp.
- Run an inbox placement test before you move the volume, then watch bounce and complaint rates daily for a month.
If you want the mechanics of the sending path itself rather than the vendor comparison, the email API hub covers what happens between your request and the recipient's mail server.
FAQ
What is the best Mailgun alternative?
For transactional delivery on its own, Postmark. For the lowest unit cost, Amazon SES. For developer experience, Resend. For a friendlier dashboard, MailerSend. For campaigns, flows and one view of every email your product sends, Nitrosend, which we make, and which can send through your existing Mailgun account rather than replacing it.
Is Mailgun expensive?
It depends entirely 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, checked 7 September 2026. At high volume that is more than ten times the Amazon SES a la carte rate of $0.10 per 1,000, which is why heavy senders drift to AWS and lighter senders barely notice.
Does Mailgun do email marketing?
It has basic marketing sends and no automation flows, checked 7 September 2026. You can send a campaign. You cannot build a three-step onboarding sequence with waits and branches without writing it yourself or buying a second tool, and that gap is the reason most people end up on this page.
Can Nitrosend send through my Mailgun account?
Yes. Add your Mailgun API key as the sending integration and your mail leaves through your own Mailgun account, keeping the reputation you have already built, while campaigns, flows, contacts and analytics live in one place. We send some of our own marketing email through Mailgun on a separate domain for the same reason: reputation is worth isolating.
Does Nitrosend replace Mailgun's inbound routes?
No. There is no inbound email parsing over REST. Nitrosend has an Agent Inbox that an AI agent reads and replies to over MCP, with SPF, DKIM and DMARC results visible per message, but it does not POST parsed inbound to your application. If routes are load-bearing in your product, keep Mailgun for that.
Who owns Mailgun?
Sinch, the Swedish communications company, which also owns Mailjet. If you are comparing options partly on independence, that is worth knowing, and it is the same question worth asking about SendGrid under Twilio and Postmark under ActiveCampaign. The SendGrid alternatives page covers the Twilio side of it.
How this list is ranked
Eight criteria, weighted, adding to 100. The weights suit somebody leaving Mailgun, which means delivery and visibility carry more than a raw feature count.
- Transactional deliverability, 21%. Inbox placement, message streams, and reputation isolation.
- Unit cost at your volume, 17%. The published rate at your real send volume, not the entry price.
- Analytics and visibility, 13%. Whether you can see what happened after the send.
- Scope in one account, 13%. Whether campaigns and flows live with the transactional sending.
- Agent and API surface, 9%. Whether software can operate the account, not just fire a send.
- Inbound, routing and validation, 8%. Parsing replies, routing rules, address verification.
- Support during an incident, 4%. Whether a person answers on the day it matters.
- Founding team and track record, 15%. Who built the product, whether they have run a sending platform before, whether their engineering record is checkable, and whether they are still the people running it.
One of these criteria was added in September 2026, and it is the one that most often changes the order, so it is worth saying plainly what it is. Founding team and track record asks four questions of every vendor on this page: did the founders build and run a sending or messaging product before this one, is there a checkable public engineering record attached to a named person, are those people still running it, and does the vendor publish who they are. Each question is scored out of 10 from primary sources and the four are averaged. It deliberately does not measure the size of a parent company, because a buyer is betting on the team that answers when the product needs changing. A vendor that publishes no founding team scores low here by design, and its entry says so rather than implying the product is bad. Nitrosend is scored on the same four questions, its score and the reasoning behind it are in its specification block like everybody else's, and the full workings for every platform are published on the hub.