REST, Node SDK, first-class MCP. Send transactional, marketing, and automation email from one API, or from inside Claude, Cursor, or ChatGPT. Unlimited contacts. Free to start.
Most transactional email APIs do one job: send a message, get a message ID, drop a webhook. That's fine until you need marketing, flows, templates, or contact management. Then you're gluing three SaaS tools together. Nitrosend is a transactional email API that also happens to be a full-stack marketing platform, so you never outgrow it.
POST to /v1/my/messages and get a message ID back before the
packet reaches your DB. Queued delivery, not blocking.
Every API endpoint has an MCP tool. Your AI agent can send transactional mail, manage contacts, or inspect delivery, without your API key ever touching its context window.
Pro and up: plug in your own sending credentials. Nitrosend handles templates, flows, logs, and AI. Your existing provider handles SMTP. No double-pay.
When marketing is ready, campaigns and flows are already wired in. No second tool, no second deliverability reputation to build.
Pick your stack. Same API, same account, same deliverability.
import { Nitrosend } from '@nitrosend/sdk';
const ns = new Nitrosend({ apiKey: process.env.NITROSEND_API_KEY });
await ns.messages.send({
from: '[email protected]',
to: '[email protected]',
subject: 'Welcome to Acme',
html: '<p>Your account is ready.</p>',
});curl -X POST https://api.nitrosend.com/v1/my/messages \
-H "Authorization: Bearer $NITROSEND_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"from": "[email protected]",
"to": "[email protected]",
"subject": "Welcome to Acme",
"html": "<p>Your account is ready.</p>"
}'import os, requests
requests.post(
"https://api.nitrosend.com/v1/my/messages",
headers={"Authorization": f"Bearer {os.environ['NITROSEND_API_KEY']}"},
json={
"from": "[email protected]",
"to": "[email protected]",
"subject": "Welcome to Acme",
"html": "<p>Your account is ready.</p>",
},
)# One-time install
claude mcp add --transport http nitrosend https://api.nitrosend.com/mcp
# Then, in Claude Code:
"Send a welcome email to [email protected] from [email protected]
with subject 'Welcome to Acme' and a short friendly body."Honest table. Pick the one that fits your stack.
| Feature | Nitrosend | Resend | Postmark | SendGrid | Amazon SES |
|---|---|---|---|---|---|
| Transactional API | ✓ | ✓ | ✓ | ✓ | ✓ |
| Marketing campaigns | ✓ | Broadcasts | Limited | Separate product | — |
| Automation flows | ✓ | Automations | — | ✓ | — |
| MCP server | 21 tools | Send-only | — | — | — |
| BYO sending keys | ✓ | — | — | — | Native |
| Contacts model | Unlimited | Audience tiers | Per server | Contact tiers | No concept |
| Free tier | 500/mo | 3,000/mo | 100/mo | 100/day | 3,000/mo (12 mo) |
| Starting paid price | $20 / 20K | $20 / 50K | $15 / 10K | $19.95 / 50K | $0.10 / 1K |
| Node SDK | ✓ | ✓ | ✓ | ✓ | ✓ |
| React Email support | ✓ | Native | — | — | — |
Pricing accurate as of April 2026. Check each vendor for latest.
Deliverability is 80% of a transactional email API. Nitrosend handles the boring parts so your email hits inboxes.
One-click domain auth. We publish the DNS records you need and verify
them in the dashboard, or via nitro_manage_domains from
your agent.
Ultra and Enterprise get dedicated IPs with warmup. Keeps your domain reputation isolated from noisy neighbours.
Hard bounces auto-suppress. Complaints auto-unsubscribe. You never accidentally re-send to a burned address.
HMAC-SHA256 on every webhook payload. Retried with exponential backoff on 4xx/5xx. Idempotency keys throughout.
Gmail, Outlook, Yahoo, Apple Mail placement tested on every send.
Spam folder rates shown in the dashboard and exposed via
nitro_review_delivery.
Global and per-account suppression. Import from your existing provider via CSV or API when you migrate.
Unlimited contacts on every plan. You only pay for the emails you actually deliver.
$0
500 emails/month. No credit card. Full API + MCP access.
20K emails/mo. BYO keys. Frontier AI models. Priority support.
100K emails/mo. Dedicated IP. 10 seats. 3 domains.
500K-4M+ emails/mo. SSO. 99.9% SLA. Unlimited seats/domains.
A transactional email API lets developers send one-to-one emails triggered by application events: signup confirmations, password resets, receipts, magic links, invoices. Unlike marketing email (sent to lists), transactional email is sent to a single recipient in response to an action. A good transactional API gives you high deliverability, low latency, webhooks for delivery events, template rendering, and clean logs.
The right API depends on your stack. Resend and Postmark are strong developer-first choices. Amazon SES is the cheapest at scale but requires you to build the platform layer yourself. Nitrosend combines transactional, marketing, and automation in one account, built AI-agent-first with a 21-tool MCP server, unlimited contacts on every plan, and optional BYO sending keys so you can keep an existing Resend or SES deliverability domain.
Yes. Nitrosend ships a first-party MCP server at
https://api.nitrosend.com/mcp. You can install it in
Claude Code, Claude Desktop, Cursor, Codex, ChatGPT, or Gemini and
send transactional email directly from the agent with OAuth. No
API key juggling.
Yes. On Pro, Ultra, and Enterprise you can BYO SendGrid, Amazon SES, Mailgun, Postmark, or Resend credentials. Nitrosend handles the platform (templates, flows, logs, AI, MCP) and your existing provider handles the actual SMTP. No double-pay, no domain reputation reset.
Nitrosend Free gives you 500 emails/month at $0. Pro is $20/month for 20,000 emails. Ultra is $100/month for 100,000 emails. Enterprise is custom for 500K+. All plans include unlimited contacts, BYO keys on paid tiers, and full MCP access. Overages are $0.19/100 on Pro and $0.15/100 on Ultra.
Yes. @nitrosend/sdk is on npm. Install with
npm i @nitrosend/sdk, then
const ns = new Nitrosend({ apiKey }) and call
ns.messages.send({ from, to, subject, html }). Python
and Ruby SDKs ship next. For non-Node environments use the REST API
directly at https://api.nitrosend.com.
Transactional email is triggered by an action and sent to one person (password reset, order receipt, magic link). Marketing email is sent to a list with consent-based targeting (newsletters, product announcements, drip campaigns). They typically run on separate sending infrastructure because their deliverability profiles differ. Nitrosend unifies both so you don't need two tools.
Sent, delivered, opened, clicked, bounced, complained, unsubscribed, and failed. Webhooks are signed with HMAC-SHA256 and retried with exponential backoff. Payloads include the original message ID, recipient, timestamp, and event-specific metadata.