I am George Hartley, co-founder of Nitrosend. The reason I care about this distinction is commercial as much as philosophical: early-stage builders will not engage with a tool that does not offer API access on the free tier. If your free plan cannot be integrated, it is not a free plan, it is a demo.
How this list is ranked
- Real API access on free, 30%. Full API, SDK and webhook access, or not a candidate.
- Monthly volume, 25%. How far you get before you pay.
- Feature gating, 20%. What is switched off. Webhooks and custom domains are the usual casualties.
- Path off the free tier, 15%. What the first paid tier costs and whether it is a cliff.
- Time limit, 10%. Perpetual free beats a 30-day trial.
Checked 3 September 2026. Free tiers change more often than any other part of a pricing page.
Free email API tiers 2026
Checked 3 September 2026| Provider | Free volume | Perpetual | Full API on free | Custom domain | Paid from |
|---|---|---|---|---|---|
| Nitrosend Full MCP, API and CLI | 8,000 then 500/mo | Yes | Yes | Yes | $20/mo |
| Brevo | 300/day | Yes | Yes | Yes | $9/mo |
| Resend | 3,000/mo | Yes | Yes | Yes | $20/mo |
| MailerSend | 3,000/mo | Yes | Yes | Yes | $24/mo |
| SendGrid | 100/day | Yes | Yes | Yes | $19.95/mo |
| Amazon SES | 3,000/mo for 12 months | New senders only | Yes | Yes | $0.10 per 1,000 a la carte |
| Mailgun | Trial only | No | Yes | Yes | $15/mo |
| Postmark | Trial only | No | Yes | Yes | $15/mo |
1. Nitrosend
Best for: building the whole email stack before you have revenue.
Every plan including free has full MCP, API and CLI access. That is the deliberate part. You get 8,000 emails to start, then 500 a month, unlimited contacts, three brands, and 20 AI actions a month.
Two caveats stated plainly, because both catch people out.
Verify a sending domain before you judge anything. Until your own domain is verified and authenticated, you are not testing your deliverability, you are testing a shared reputation you do not control. Verify the domain first, then measure. The Free plan allows 100 / 500 / 5,000 recipients per rolling 24 hours for Free Probation / Standard / Trusted, so plan a real test around that rather than around the monthly total.
Email validation is prepaid on every plan. There is no included validation allowance on free, or on any tier. It is a separate prepaid balance you top up deliberately.
Internally we have argued about whether 500 a month is generous enough, and I have made the case for raising it. Take the current number as the current number and check the pricing page rather than this sentence.
- Nitrosend at a glance
- Verified on the vendor's own pages
- Best for
- building the whole email stack before you have revenue
- 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
- Limitations
- No cold outreach
- No inbound email parsing over REST, the Agent Inbox is MCP-only
- Not the cheapest at high transactional volume, where Amazon SES wins
- Facts checked
2. Brevo
Best for: the highest sustained free volume.
300 a day, so around 9,000 a month, which is the most generous perpetual free tier here by volume. Full API access, marketing and transactional in one account. The tradeoff is that the free tier carries Brevo branding and the product is broader and less focused than the developer-first options.
- Brevo at a glance
- Verified on the vendor's own pages
- Best for
- the highest sustained free volume
- 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
- Limitations
- The free tier carries Brevo branding
- Broader and less focused than the developer-first options
- Sending starts only once the account is approved
- Facts checked
3. Resend
Best for: a free tier you will enjoy using.
3,000 a month, 100 a day, full API, and the best documentation in the category. React Email is free and genuinely good. The daily cap matters if your sending is bursty. It remains the cleanest developer experience on this list.
- Resend at a glance
- Verified on the vendor's own pages
- Best for
- a free tier you will enjoy using
- 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
- Limitations
- The 100 a day cap matters if your sending is bursty
- The free plan includes only 5 AI credits a month
- Marketing features are the simple end
- Facts checked
4. MailerSend
Best for: free templates alongside free sending.
3,000 a month with the template builder included, which is unusual on a free tier. Straightforward API, no serious gating.
- MailerSend at a glance
- Verified on the vendor's own pages
- Best for
- free templates alongside free sending
- 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
- Limitations
- No marketing campaigns or automation flows
- Plan volumes are slider-driven rather than published
- No MCP server
- Facts checked
5. SendGrid
Best for: teams who will scale into Twilio.
100 a day, perpetual, full API. The daily cap is restrictive and the free tier has become progressively more locked down, but it is a real free plan on mature infrastructure.
- SendGrid at a glance
- Verified on the vendor's own pages
- Best for
- teams who will scale into Twilio
- Pricing model
- hybrid
- Free tier
- 60-day free trial, 100 emails a day, no credit card
- Entry paid plan
- $19.95/mo (50,000 emails a month, Email API, analytics and deliverability tooling; taxes and overages extra)
- At 100,000 emails a month
- $34.95/mo (Essentials 100k)
- Transactional API
- yes
- Marketing campaigns
- yes
- Automation flows
- yes
- SMS
- no
- Inbound email parsing
- yes
- Owner
- Twilio
- Support
- Help center: support.sendgrid.com
- Developer docs
- API documentation: twilio.com/docs/sendgrid
- Status page
- System status: status.sendgrid.com
- Pricing page
- Current pricing: twilio.com/en-us/products/email-api/pricing
- Limitations
- The 100 a day cap is restrictive
- The free tier has become progressively more locked down
- Transactional and marketing are separate products
- Facts checked
6. Amazon SES
Best for: nearly free rather than free.
SES gives new senders up to 3,000 message charges a month for the first twelve months, and beyond that the price is $0.10 per 1,000 on a la carte pricing or $0.16 on the Essentials plan that new accounts default to since 21 July 2026. What it costs you is setup: sandbox removal requires a support request, and reputation management is yours.
- Amazon SES at a glance
- Verified on the vendor's own pages
- Best for
- nearly free rather than free
- 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
- Limitations
- Free usage varies by account and region
- Sandbox removal requires a support request
- Reputation management is yours
- Facts checked
7. Mailgun and 8. Postmark
Both are trial rather than free. Postmark's trial is generous and the product is excellent, but there is no perpetual free tier, so neither belongs in a side project's long-term plan. Both are worth paying for once you have revenue.
- Mailgun at a glance
- Verified on the vendor's own pages
- Pricing model
- per send
- Free tier
- 100 emails a day
- Entry paid plan
- $15/mo (included monthly emails, overage from $1.80 per 1,000)
- Transactional API
- yes
- Marketing campaigns
- yes
- Automation flows
- no
- SMS
- no
- Inbound email parsing
- yes
- Owner
- Sinch
- Support
- Help center: help.mailgun.com
- Developer docs
- API documentation: documentation.mailgun.com
- Status page
- System status: status.mailgun.com
- Pricing page
- Current pricing: mailgun.com/pricing
- Limitations
- Trial rather than a perpetual free plan
- Does not belong in a side project's long-term plan
- Marketing features are limited
- Facts checked
- Postmark at a glance
- Verified on the vendor's own pages
- 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
- Limitations
- No perpetual free tier
- Does not belong in a side project's long-term plan
- No marketing layer
- Facts checked
The trap in every free tier
Free tiers are priced to be outgrown, and the interesting number is not the free volume but the first paid tier. A plan that gives you 3,000 free and then jumps to $20 for 50,000 is a slope. A plan that gives you 100 a day and then requires an enterprise conversation is a cliff.
The second thing to check is what the free tier switches off. Webhooks and custom sending domains are the common casualties, and both are load-bearing. Without a custom domain you cannot authenticate, and without SPF and DKIM your deliverability on any tier is a coin flip. A free tier that will not let you verify a domain cannot teach you anything about how your email will actually perform.
Third, do not benchmark deliverability on a free tier, and do not benchmark it by eye either: use a seed placement test on a verified domain. Free accounts on every platform sit on shared infrastructure with the noisiest senders on the service. Your results will improve when you pay, on any provider here, and that is not a trick.
FAQ
What is the best free email API?
Nitrosend for full MCP, API and CLI access with 8,000 sends then 500 a month. Brevo for the highest ongoing free volume at 300 a day. Resend for the best developer experience.
Is there a free email API with no credit card?
Yes. Nitrosend, Brevo, Resend, MailerSend and SendGrid all have perpetual free tiers requiring no card. Postmark and Mailgun are trials.
Can I use a free email API in production?
For low volume, yes, provided you can verify a custom sending domain and authenticate it. Do not run production transactional email on a tier that blocks custom domains.
What is the catch with free email APIs?
Usually one of three: a daily cap that breaks bursty sending, feature gating on webhooks or custom domains, or a steep first paid tier. Check all three before you build.
Which free email API has the highest limit?
Brevo at 300 a day. Nitrosend gives the largest initial allowance at 8,000 before settling to 500 a month.