Best free email APIs in 2026
Unitpost has the best free email API plan for most apps: 5,000 emails a month with no card, plus the API, SMTP relay, webhooks, inbound email and marketing campaigns on the free plan. Brevo sends more for free (300 a day), Resend gives 3,000 a month, and Postmark's free plan never expires but holds 100 emails.
Updated November 2, 2026. We make Unitpost, and it is on this list. Every score has a reason and the weights are published below, so you can re-rank it for your own needs. How we scored
| # | Product | Best for | Score |
|---|---|---|---|
| 1 | Unitpost | a free plan you can launch on | 4.6 |
| 2 | Brevo | the most free emails | 4.0 |
| 3 | Resend | a developer-first free tier | 3.8 |
| 4 | Loops | SaaS teams that also send campaigns | 3.2 |
| 5 | MailerSend | a cheap first paid plan | 3.1 |
| 6 | Postmark | testing before you pay | 2.9 |
| 7 | Mailgun | trying a high-volume API | 2.8 |
The picks
#1 · 4.6 / 5
Unitpost
Best for a free plan you can launch on5,000 emails a month with the whole product switched on: API, SMTP, webhooks, inbound and campaigns. The first paid step is $10 a month.
Pros
- 5,000 emails a month, no card, no expiry
- Inbound email, campaigns and the MCP server on the free plan
- Up to 5 sending domains on free
- $10 a month for 20,000 emails when you outgrow it
Cons
- A 200-a-day cap on free
- One team seat and 7 days of logs on free
- Free plan
- 5,000 emails a month, 200 a day, no card
- Paid from
- $10 a month for 20,000 emails
- Priced by
- Emails sent
#2 · 4.0 / 5
Brevo
Best for the most free emailsThe biggest free volume here, inside a marketing suite with a transactional API and SMTP relay. Free sending starts once Brevo approves the account.
Pros
- 300 emails a day, about 9,000 a month
- API, SMTP relay and campaigns on the free plan
- Starter from $9 a month
Cons
- Sending starts after account approval
- The API serves a marketing suite first
- Free plan
- 300 emails a day
- Paid from
- $9 a month for 5,000 emails
- Priced by
- Emails sent
#3 · 3.8 / 5
Resend
Best for a developer-first free tierA modern API with 3,000 free emails a month, inbound email and 1,000 marketing contacts on free. The daily cap is 100.
Pros
- A modern API with clear errors and many SDKs
- Inbound email and 1,000 marketing contacts on free
- Three domains on the free plan
Cons
- Capped at 100 emails a day
- One webhook endpoint on free
- Free plan
- 3,000 emails a month, 100 a day
- Paid from
- $20 a month for 50,000 emails
- Priced by
- Sends and contacts
#4 · 3.2 / 5
Loops
Best for SaaS teams that also send campaignsEmail for SaaS products with campaigns, workflows and transactional sends on one free plan, priced by contacts once you grow.
Pros
- Campaigns, workflows and transactional email on free
- 4,000 sends a month
- An official hosted MCP server
Cons
- At most 1,000 subscribed contacts on free
- A Loops footer on free, and transactional sends need a published template
- Free plan
- 1,000 contacts and 4,000 sends a month
- Paid from
- $49 a month for up to 5,000 contacts
- Priced by
- Contacts
#5 · 3.1 / 5
MailerSend
Best for a cheap first paid planA transactional email API with a small free plan and the cheapest first paid step here. Free covers the API and SMTP on one domain.
Pros
- API and SMTP on the free plan
- Hobby is $7 a month for 5,000 emails
- An official hosted MCP server
Cons
- 500 emails a month on free, and the free plan needs a card
- One domain, one template and 100 API requests a day on free
- Free plan
- 500 emails a month, card required
- Paid from
- $7 a month for 5,000 emails
- Priced by
- Emails sent
#6 · 2.9 / 5
Postmark
Best for testing before you payA developer plan that never expires, for testing Postmark's well-regarded transactional sending. It holds 100 emails a month.
Pros
- Never expires, no overages
- API, SMTP and inbound on the free plan
- A strong deliverability record when you upgrade
Cons
- 100 emails a month
- Bulk email isn't on the free plan
- Free plan
- 100 emails a month
- Paid from
- $15 a month for 10,000 emails
- Priced by
- Emails sent
#7 · 2.8 / 5
Mailgun
Best for trying a high-volume APIA permanent free plan of 100 emails a day on one domain, on an API built for volume. Logs last a day on free.
Pros
- 100 emails a day, permanently
- One inbound route on free
- Proven at very high volume when you grow
Cons
- One domain and one day of logs on free
- HTTP Basic auth instead of a bearer token
- Free plan
- 100 emails a day on one domain
- Paid from
- $15 a month for 10,000 emails
- Priced by
- Emails sent
Scores side by side
| Product | Free volume30% | What's included25% | No strings15% | Developer experience20% | First paid step10% | Total |
|---|---|---|---|---|---|---|
| Unitpost | 4 | 5 | 4 | 5 | 5 | 4.6 |
| Brevo | 5 | 4 | 3 | 3 | 4 | 4.0 |
| Resend | 3 | 4 | 4 | 5 | 3 | 3.8 |
| Loops | 3 | 4 | 3 | 3 | 2 | 3.2 |
| MailerSend | 2 | 3 | 3 | 4 | 5 | 3.1 |
| Postmark | 1 | 3 | 5 | 4 | 3 | 2.9 |
| Mailgun | 3 | 2 | 3 | 3 | 3 | 2.8 |
How we scored
This list is for developers who need app email at no cost: side projects, prototypes and early products. What matters to them: how much the free plan sends, what it includes, the strings attached, and what the first paid step costs once the app grows.
- Free volume (30%). Emails a month on the free plan, for good, and how tight the daily cap is.
- What's included (25%). API and SMTP, domains, webhooks, inbound and marketing email on the free plan.
- No strings (15%). It never expires and needs no card, approval or footer.
- Developer experience (20%). A clear REST API, current SDKs, readable errors and docs.
- First paid step (10%). A cheap first paid plan that grows with sends.
Each product gets 1 to 5 per criterion, from its own pricing and docs pages. The total is the weighted mean, so changing a weight re-ranks the list.
Why Unitpost scored 4.6
- Free volume: 4/5. 5,000 emails a month, capped at 200 a day.
- What's included: 5/5. API, SMTP, webhooks, inbound, campaigns and the MCP server all work on free.
- No strings: 4/5. No card and no expiry; one seat and 7 days of logs.
- Developer experience: 5/5. Bearer-token REST API, nine SDKs, a CLI and an MCP server, with idempotency keys on sends.
- First paid step: 5/5. $10 a month for 20,000 emails, priced by sends.
Checked November 2, 2026 against unitpost.com/pricing, unitpost.com/sms, registry.npmjs.org/unitpost.
Why Brevo scored 4.0
- Free volume: 5/5. 300 emails a day, the most of any free plan here.
- What's included: 4/5. API, SMTP relay and campaigns are on the free plan.
- No strings: 3/5. Permanent, but sending starts once Brevo approves the account.
- Developer experience: 3/5. A full API and SMTP relay, shaped by the marketing suite rather than built for developers first.
- First paid step: 4/5. Starter from $9 a month, sized by email volume.
Checked November 2, 2026 against brevo.com/pricing/, developers.brevo.com/docs/mcp-protocol, help.brevo.com/hc/en-us/articles/7959631848850, help.brevo.com/hc/en-us/articles/360021533839, registry.npmjs.org/@getbrevo/brevo.
Why Resend scored 3.8
- Free volume: 3/5. 3,000 emails a month, capped at 100 a day.
- What's included: 4/5. API, SMTP, inbound and broadcasts to 1,000 contacts; one webhook.
- No strings: 4/5. A permanent plan; limits sit on domains and webhooks.
- Developer experience: 5/5. The API many newer providers copy, with SDKs across most languages.
- First paid step: 3/5. Pro is $20 a month for 50,000 emails; marketing contacts are a second plan.
Checked November 2, 2026 against resend.com/pricing, resend.com/migrate, resend.com/docs/dashboard/receiving/introduction, github.com/resend/mcp-send-email, resend.com/docs/send-with-smtp, resend.com/docs/api-reference/api-keys/create-api-key, registry.npmjs.org/resend, resend.com/docs/dashboard/webhooks/retries-and-replays.
Why Loops scored 3.2
- Free volume: 3/5. 4,000 sends a month, to at most 1,000 subscribed contacts.
- What's included: 4/5. Transactional API, SMTP, campaigns and workflows on free.
- No strings: 3/5. Free emails carry a Loops footer.
- Developer experience: 3/5. A clean API, but transactional sends must use a template published in Loops.
- First paid step: 2/5. Growth is $49 a month, priced by contacts.
Checked November 2, 2026 against loops.so/pricing, loops.so/docs/transactional, loops.so/docs/mcp-server.
Why MailerSend scored 3.1
- Free volume: 2/5. 500 emails a month.
- What's included: 3/5. API and SMTP on one domain, with one template.
- No strings: 3/5. A permanent free plan, but it needs a card, and limits domains, templates and API requests.
- Developer experience: 4/5. A modern REST API, SMTP and an official MCP server.
- First paid step: 5/5. Hobby is $7 a month for 5,000 emails.
Checked November 2, 2026 against mailersend.com/pricing, developers.mailersend.com/mcp, mailersend.com/help/smtp-relay, mailersend.com/features/inbound-emails, developers.mailersend.com/api/v1/webhooks.html, registry.npmjs.org/mailersend, developers.mailersend.com/api/v1/inbound.
Why Postmark scored 2.9
- Free volume: 1/5. 100 emails a month.
- What's included: 3/5. API, SMTP and inbound; no bulk sending.
- No strings: 5/5. The developer plan never expires and has no overages.
- Developer experience: 4/5. A mature, well-documented API with official libraries.
- First paid step: 3/5. Basic is $15 a month for 10,000 emails.
Checked November 2, 2026 against postmarkapp.com/pricing, postmarkapp.com/migration-guides, postmarkapp.com/lp/mcp, postmarkapp.com/developer/user-guide/send-email-with-smtp, registry.npmjs.org/postmark, postmarkapp.com/developer/webhooks/inbound-webhook.
Why Mailgun scored 2.8
- Free volume: 3/5. 100 emails a day, about 3,000 a month.
- What's included: 2/5. One domain, one inbound route and one day of logs.
- No strings: 3/5. Permanent, but one day of logs makes debugging hard.
- Developer experience: 3/5. A capable API on HTTP Basic auth, with a surface shaped by long history.
- First paid step: 3/5. Basic from $15 a month for 10,000 emails.
Checked November 2, 2026 against mailgun.com/pricing/, mailgun.com/resources/guides/migrating-from-sendgrid-to-mailgun-email-api/, documentation.mailgun.com/docs/mailgun/mcp, documentation.mailgun.com/docs/mailgun/user-manual/sending-messages/send-smtp, registry.npmjs.org/mailgun.js, documentation.mailgun.com/docs/mailgun/user-manual/receive-forward-store/receive-http.
Frequently asked questions
Which email API has the biggest free plan?
Is there a free SendGrid plan?
What should a free email plan include?
Go deeper: Pricing · Unitpost vs Resend · Unitpost vs Brevo · Check your domain
Start free
Start sending email your users actually receive
5,000 emails a month free — full API, SMTP relay, templates, tracking, and webhooks. Create a key, verify a domain, and send in minutes. No credit card.