Unlimited domains, free. Receive email as a webhook, send with one API. No credit card required. Start in under 5 minutes.
| MailKite | SendGrid | Mailgun | |
|---|---|---|---|
| Domains | Unlimited, free | 1 (free tier) | 1 (free tier) |
| Inbound email | Webhook, clean JSON | Multipart parse | Inbound routes |
| Outbound sends | Free tier included | 100/day limit | 5,000/month |
| SDKs | 8 languages | 8 languages | 7 languages |
| MCP / AI agents | Native support | Not available | Not available |
| Credit card required | No | No (but limited) | No (but limited) |
Add as many domains as you need. Each gets its own inbound routes, webhook targets, and sending identity. No per-domain charges.
Every incoming email parsed into clean JSON and POSTed to your endpoint. No multipart form decoding, no MIME assembly.
Transactional email via REST API or SDK. DKIM signing, deliverability tracking, and bounce handling built in.
Sign up, get an API key, start sending. No payment info required. Upgrade only when you need to.
Yes. MailKite is free on unlimited domains with no credit card required. The free tier includes inbound email webhooks, outbound sending, and dashboard access. You pay only when you need higher volume.
Unlimited domains, inbound email as webhook, outbound send API, SDKs for every language, HMAC-signed payloads, built-in threading, and full dashboard access. No feature gating on the free tier.
SendGrid's free tier is limited to 100 emails/day and 2,000 contacts. MailKite's free tier has unlimited domains and no daily send cap — you pay only when volume grows past the free threshold.
MailKite uses graceful overage — your service never stops. You're notified when approaching limits and can upgrade with one click. No surprise cutoffs, no silent suspensions.
Unlimited domains, free. No credit card. Under 5 minutes to first email.