Sendmark
Transactional messaging API

Every message your app sends, through one API

Email, SMS, WhatsApp, webhooks, Slack and Discord — one endpoint, one key, and delivery you can trace end to end.

Start freeView the API
  • 5,000 free credits a month
  • No card required
  • Six channels
  • Automatic retries
  • Idempotency keys
  • Delivery webhooks
  • Transactional only
The API

One endpoint, every channel

Change one field to switch channel. Same auth, same response shape, same delivery events.

curl https://api.sendmark.dev/v1/messages \
  -H "Authorization: Bearer $SENDMARK_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "channel": "email",
    "to": "[email protected]",
    "from": "[email protected]",
    "subject": "Your invoice is ready",
    "template": "invoice_ready",
    "data": { "amount": "$42.00" }
  }'

message.delivered · msg_01j9k2m3n4p5

Delivered to [email protected] in 1.2s

Channels, one API
6
Delivery rate
99.9%
Median API response
<120ms
Marketing email carried
0
Channels

Every channel your users are on

The same endpoint, the same auth and the same delivery guarantees, whichever channel you send through.

1 credit

Email

Transactional email with high deliverability, reusable templates and open and click tracking.

75 credits

SMS

Global SMS delivery with automatic carrier failover, unicode support, and delivery receipts.

70 credits

WhatsApp

Reach customers on WhatsApp with approved message templates, delivered through your own Business account.

Free

Webhook

Signed HTTP callbacks to your own systems with configurable retries and backoff.

Free

Discord

Post rich, formatted alerts to Discord channels through your own server bot.

Free

Slack

Send interactive messages to Slack channels, threads, or direct messages.

More on the way

Same API, no extra setup when they land.

  • Telegram
  • Push
Acceptable use

Transactional only, on every plan

Sending IPs and domains are shared between customers. One marketing blast would cost everyone else their inbox placement, so marketing and bulk sending are refused at the API rather than discouraged in fine print.

What Sendmark carries

  • Password resets, verification and one-time codes
  • Receipts, invoices and order confirmations
  • Shipping and delivery updates
  • Account, billing and security alerts
  • Appointment and booking confirmations
  • Support replies and system alerts to your own channels

What is refused

  • Newsletters, digests and product announcements
  • Promotions, discounts, coupons and cross-sells
  • Anything carrying an unsubscribe footer
  • The same content sent to many recipients
  • Phishing, malware links and executable attachments
  • Gambling, adult, pharmaceutical and crypto spam

Every message is screened before it is sent

Messages that fall outside the policy are refused with a clear error, and repeated attempts suspend the account. You can see your standing and any refused sends in the dashboard at any time.

Pricing

Pay for messages, not channels

One pool of credits per month. Spend it on email, SMS, WhatsApp, webhooks, Slack or Discord — whichever you actually send.

Free

$0/mo

For side projects and testing.

  • 5,000 emails a month
  • Webhooks — unlimited
  • Slack — unlimited
  • Discord — unlimited
  • No SMS or WhatsApp
  • 2 team members
  • 3-day log retention
  • Community support
Start free

Starter

$9/mo

For apps with real users.

  • 20,000 emails a month
  • or 266 SMS
  • or 285 WhatsApp
  • Webhooks — unlimited
  • Slack — unlimited
  • Discord — unlimited
  • 5 team members
  • 14-day log retention
  • Email support
Choose Starter

Pro

Most popular

$49/mo

For teams at steady volume.

  • 150,000 emails a month
  • or 2,000 SMS
  • or 2,142 WhatsApp
  • Webhooks — unlimited
  • Slack — unlimited
  • Discord — unlimited
  • Dedicated sending IP
  • 20 team members
  • 30-day log retention
  • Priority support
Choose Pro

Business

$149/mo

For high volume with an SLA.

  • 600,000 emails a month
  • or 8,000 SMS
  • or 8,571 WhatsApp
  • Webhooks — unlimited
  • Slack — unlimited
  • Discord — unlimited
  • Dedicated IP included
  • Unlimited team members
  • 90-day log retention
  • 99.9% uptime SLA
Talk to sales
  • No card on the free plan
  • Cancel any time
  • Unused credits carry over when you upgrade

What a credit buys

One credit is one email. SMS and WhatsApp cost more because carriers and Meta charge us per message. Webhooks, Slack and Discord are free on every plan.

Email
1 credit per message
WhatsApp
70 credits per conversation
SMS
75 credits per segment
Webhook
Free · unlimited
Slack
Free · unlimited
Discord
Free · unlimited

Transactional messages only, on every plan — that is what keeps delivery rates high for everyone here.

Frequently asked questions

Can't find what you're looking for? Email [email protected].

Send your first message today

Create an account, generate a key and send in minutes. 5,000 emails a month, free, no card required.

Start freeSee pricing

Transactional messages only — marketing and bulk sending are not permitted.