KumoMTA vs Bird Email (2026): which should you pick?
As of Nov 13, 2026, Bird Email grades higher than KumoMTA: 2.6 against 2.2 out of 4.0.
Checked Nov 9, 2026 and Nov 13, 2026 · graded Oct 18, 2026 and Nov 13, 2026 by ToolGPA
KumoMTA grades higher on the free plan. Bird Email grades higher on value for money, ease of use and platforms. They get the same grade on features.
Price, platforms and features side by side. The table says where each price was read and when.
KumoMTA
Open-source mail server for high-volume, self-run email sending
Bird Email
SparkPost's successor: Bird's email API, paid from a prepaid balance
Which one is for you
Pick KumoMTA if
- Fits if you're an engineering team running your own high-volume sending
- Works for senders moving off a commercial mail server who can write Lua
Look elsewhere if
- Skip it if you want a point-and-click setup, since configuration is done in Lua
- Tight if you need support: Silver is business hours only, and Enterprise has no published price
- Not for you if you want a hosted service, as you run it yourself
- Watch out: the pages don't say which operating systems are supported
Pick Bird Email if
- Fits if your app sends texts or WhatsApp messages alongside email
- Works for apps that give AI agents mailboxes of their own
Look elsewhere if
- Skip it if you want a fixed monthly allowance, since every email draws on a balance shared with other Bird products
- Pricey if you need a dedicated IP, which starts with the $250 Growth plan
- Tight if you're staying free, at 50 emails a day and 1 sending domain, and sending stops at the limit
- Watch out: Bird Email has its own API, so SparkPost integrations need reviewing before you move traffic
How we grade them
| 2.2GPAKumoMTAFair | 2.6GPABird EmailGood | |
|---|---|---|
| Value for money | CThe software is free under Apache 2, but you host it yourself, and paid support starts at $5,000 per billion messages a year. | BGraded on 50,000 emails a month, worked out from the listed rate: Startup charges $0.40 per 1,000, so that's $20 of balance a month, more than its $15 deposit covers. Unused balance carries forward. That's in the lowest-priced quarter of this category at that volume. |
| Free plan and trial | BEvery feature is free to run, with community help on Discord. You do need your own server to use any of it. | CFree for good: 1,000 emails a month, but only 50 a day and 1 sending domain, and sending simply stops at the limit. Enough to try the API, not to run an app on. |
| Features | BHigh-volume sending, Lua policy scripting, traffic shaping and IP pools, with hooks into Kafka, AMQP, Prometheus, Grafana and Vault. Nothing in the listing shows a gap in the job. | BAPI, SMTP, typed SDKs, a CLI and an MCP server, inbound email and mailboxes, signed webhooks, DKIM and DMARC setup, templates and broadcasts, with SMS and WhatsApp on the same API. It covers the job; dedicated IPs start at $250. |
| Ease of use | DNo store rating on record. It's configured in Lua scripting on your own servers, so it suits engineers. | CJudged on how fast a developer sends a first email: SDKs for TypeScript, Python, Go and PHP plus a CLI, once a domain is set up. No rating on record. Coming from SparkPost means a new API, which Bird says to review with its team. |
| Platforms and integrations | CSoftware for your own servers, listed for Linux, with Docker and Kubernetes. No dashboard or hosted version. | BWeb, with an API, SMTP, SDKs, a CLI and an MCP server, plus Claude, ChatGPT, Cursor, GitHub Copilot, Replit, Lovable, v0 and Bolt. No desktop or phone app, so B is the top. |
| Best for | a free high-volume mail server you run yourself | email, SMS and WhatsApp through one API |
The GPA is the average of the five grades: an A is 4 points, an F is none. The full reasons are on each tool's page: KumoMTA and Bird Email. How we grade
Price against what you get
KumoMTA starts at $416.67 a month when paid by the year and scores 2.0 out of 4 on features, ease of use and platforms. Bird Email starts at $15 a month and scores 2.7.
Bird Email scores higher and starts $401.67 a month lower. Of the other email sending services on the chart, 30 score higher than KumoMTA for less, and none scores higher than Bird Email for less.
Features, ease of use and platforms, averaged
What paid plans start at, a month (each step along is roughly double) →
- The best score at each price
- Has a free plan
- No free plan
Where they differ
- KumoMTA is open source and self-hostable, according to its own site.
- Bird Email also covers email campaigns.
At a glance
| KumoMTA | Bird Email | |
|---|---|---|
| Pricing | Free plan | Free plan |
| Starts at | $5,000 per billion messages per year for Silver support | $15 per month, deposited to your Bird balance |
| Free plan | The software and all its features are free under the Apache 2 license; community support runs through a Discord server. | 1,000 emails a month, limited to 50 a day, 1 sending domain, 5 mailboxes and 3 webhook endpoints. Sending stops at the limit. |
| Free trial | None listed | None listed |
| Web | ||
| Linux | ||
| Made by | Kumo Corp | Bird B.V. |
| Price read from | kumomta.com | bird.com |
| Checked | Nov 13, 2026 | Nov 9, 2026 |
Worth knowing
KumoMTA
- It is software you run yourself on your own servers; the pages do not say which operating systems are supported.
- Support is priced per billion messages a year with no server limit; Silver is business hours only, and Enterprise has no published price.
- Configuration is done in Lua scripting, so it suits engineers, not a point-and-click setup.
Bird Email
- Bird Email has its own API: Bird says SparkPost integrations should be reviewed with an account team before moving traffic.
- Paid plans are deposits, not allowances: every email is charged at the plan's rate, and other Bird products draw on the same balance.
- Dedicated IPs and IP pools start with the $250 Growth plan.
- The free plan is limited to 50 emails a day and 1 sending domain.
Key features
KumoMTA
- High-volume sending
- The vendor says a single server can send several million messages an hour, and that it can scale out with Docker and Kubernetes.
- Lua policy scripting
- Behavior is set in Lua scripts, with policy helpers for common configurations.
- Integrations for operations
- Supports webhooks, AMQP, Kafka, Vault, Prometheus, Grafana and direct database access.
- Traffic shaping and IP pools
- A customer quote on the site names traffic shaping and IP pool automation as the parts it builds on.
- Migration guides
- The site has a migration center with pages for moving from Momentum, PowerMTA, Halon, SendGrid and Hurricane MTA.
- Open source
- Released under the Apache 2 license, with the source code on GitHub.
Bird Email
- Email API, SMTP, SDKs and MCP
- Send through the API or SMTP relay, with typed SDKs for TypeScript, Python, Go and PHP, a CLI and a hosted MCP server for AI assistants.
- Mailboxes for agents
- Mailboxes that send, receive and store email for your app or AI agents: 5 on Free, 10 on Startup, 25 on Growth and 100 on Scale.
- Deliverability controls
- DKIM signing, SPF alignment, DMARC setup, suppression lists and managed dedicated IPs warmed over about 30 days, from the Growth plan.
- Analytics and signed webhooks
- Delivery, bounce, complaint, open and click data by domain, inbox provider and IP, plus signed, replay-protected webhooks for every event.
- Templates and campaigns
- Send raw HTML or React Email templates, and run broadcasts to opted-in audiences from the same platform.
- One API for other channels
- The same send call and webhook format cover Bird's SMS, WhatsApp and voice products, so a code can fall back from email to text.
Plans
KumoMTA
Community$0
Free software with every feature. Help comes from the community Discord server; you host it yourself.
Silver$5,000
per billion messages per year
Business-hours support (9-5 US Eastern) by email and portal, a shared sponsor Discord channel and help with basic configuration.
Gold$10,000
per billion messages per year
Support 8-7 US Eastern, a 24/7 critical-issue SLA, a private Discord and help with custom Lua policy.
EnterpriseCustom
24/7/365 support, telephone support, a private Discord or Slack channel and refactored policy scripts. No price is stated; contact the vendor.
Bird Email
Free$0
1,000 emails a month and 50 a day, 1 sending domain, 5 mailboxes, inbound email and templates.
Startup$15
per month, deposited to your balance; email at $0.40 per 1,000
About 37,500 transactional emails if the whole deposit goes on email. 10 sending domains, 10 mailboxes, no daily limit; unused balance carries forward.
Growth$250
per month, deposited to your balance; email at $0.45 per 1,000
About 555,555 emails from the deposit. 500 sending domains, up to 5 dedicated IPs and IP pools, 25 mailboxes, 10 webhook endpoints.
Scale$1,000
per month and up, deposited to your balance; $0.35 per 1,000 at $1,000
Deposits of $1,000, $2,500, $5,000 or $10,000 a month; the page gives a rate only for the $1,000 step. 1,000 domains, up to 10 dedicated IPs, 100 mailboxes.
Common questions
Which is cheaper, KumoMTA or Bird Email?
As of Nov 13, 2026, Bird Email is cheaper to start with: $15 a month, against $416.67 a month when paid by the year for KumoMTA. KumoMTA starts at $5,000 per billion messages per year for Silver support, and Bird Email starts at $15 per month, deposited to your Bird balance.
Which has a free plan, KumoMTA or Bird Email?
As of Nov 13, 2026, both KumoMTA and Bird Email have a free plan.
Which platforms do KumoMTA and Bird Email run on?
As of Nov 13, 2026, only KumoMTA lists a Linux app and only Bird Email lists a web app. A platform missing from a listing is one its maker's pages did not mention.
More comparisons
How this page was made
- The verdict at the top follows a fixed rule. When both tools are in the same category and either is in our top three for it, the verdict follows that ranking: the higher-placed tool is our pick. The top three weigh who each tool suits as well as its grades, so a pick can go against the GPA. Otherwise the page does not pick one and says which grades higher: the higher GPA first; on a tie, the one with a free plan, then the one that starts cheaper in dollars a month, counted the same way for both; if they are still level, what the choice depends on.
- The grades are our own, from each tool’s review or report card. The GPA is their average.
- Prices, plans and platforms come from each tool’s listing. The table above says where each price was read and when.
- The differences and the answers to the questions are worked out from those listings.