One API for transactional email and one-time codes — the same token, the same events, the same place to look when you need to know what happened.
No credit card · 200 emails a day, free for 100 days
qmx_live_•••
voce@suaempresa.com
Ana Souza replied to your receipt
your inboxYour Company <no-reply@yourcompany.com>
Your receipt #4821
Thanks! Your order is confirmed and on its way…
Ana Souza <ana@cliente.com>
Re: Your receipt #4821 — can you send the invoice too?
Verify your sign-in
/api/v1/verify/check
email · otp out by API — and the replies land in the inbox you already use
The products
Each one answers a different need and is bought separately. What they share is the part that usually costs you time: one way to authenticate, one statement, and one place to look when something does not arrive.
The same authentication, the same webhook events, the same invoice. Adding a channel is not onboarding another vendor — it is calling another endpoint with the token you already have.
Why Quathos Mailer
Verify a sender, create a scoped token, POST. Everything after that is recorded — message by message.
Authentication and reputation decide where your email lands. We handle both, and tell you which one it was.
POST /v1/emails202Delivered to the inbox
Every outcome comes back as a webhook
Sent from our own MTA — SPF, DKIM, DMARC and forward-confirmed reverse DNS all in place, so mailbox providers trust the source before they even read the message.
Real-time events
The moment a message is delivered, opened, clicked, bounces or draws a complaint, the event is pushed to your endpoint — no polling, no guesswork.
msg_01JQ4C…a7vrf_01JQ4C…c9Confirm an email address or authenticate your domain.
Generate a scoped token, or a 7-day test token to try it out.
POST to the API and track delivery in real time.
Developer-first
Copy, paste, send. Client libraries optional.
Get startedPoint your existing code at us — the /v3/mail/send payload you already send is accepted as-is. Bring your suppression list and templates with a read-only key, and you can be sending the same afternoon.
No credit card — 200 emails/day free for 100 days.
Swap the base URL and the token. Our /v3/mail/send compatibility endpoint accepts the payload you already build — no rewrite.
Paste a read-only API key from your old account. We import bounces, complaints, unsubscribes and blocks — the part that protects your reputation.
Handlebars renders as-is — {{#if}}, {{#each}}, {{this.x}} and friends. Anything outside that subset arrives as a draft, never published half-converted.
Pricing
Start free with 200 emails a day for 100 days. Move up only when you need more volume. No contracts, cancel anytime.
For trying Quathos Mailer out
200 emails / day
free for 100 days, then pick a plan
What's included
For small, steady sending
50,000 emails / month
then $0.0008 per extra email
What's included
Best price per email
150,000 emails / month
then $0.0006 per extra email
What's included
For high-volume senders
500,000 emails / month
then $0.0004 per extra email
What's included
Custom volume with dedicated support
Let's tailor it to your volume
What's included
Prices in USD, billed monthly. Only email sends count toward your quota.
FAQ
Everything you need to know before your first send. Still unsure? Talk to us.
One HTTP call sends the message; the event trail tells you what happened to it — delivered, opened, bounced, each pushed as a signed webhook. Verify a sender, create a scoped token, POST: welcome messages, receipts, one-time codes. Templates, per-tenant isolation and suppression handling are part of the same surface, not add-ons.
Minutes. Create an account, confirm a single sender address (or authenticate a whole domain), generate an API token, and POST your first message. No sales call, no credit card — your trial gives you 200 emails a day for 100 days.
Simple monthly plans by volume, priced in USD. Every plan includes a monthly email quota that is already paid for by the subscription — sends inside your quota never touch your wallet. Only usage beyond the quota draws on prepaid credit. No hidden per-send fees, no surprise overages.
Yes. Verifying a domain is publishing three CNAMEs and a DMARC record — your existing SPF is never touched — and we never send from an unverified sender. Bounces and complaints come back as events, and suppressed addresses are honored on every send. Bounce and complaint rates are the two numbers reputation is built on; both are measured and visible per message.
Every message emits events — delivered, opened, clicked, bounced, complained — pushed to your endpoint in real time as they happen. Each delivery is signed and retried on failure, so you get an accurate, ordered picture of what reached your recipients without polling.
Tokens are scoped and shown only once, at creation — we store a hash, never the full secret. Every tenant is isolated at the database level, marketing and transactional streams are separated from the schema up, and we never log passwords, codes or provider credentials.
Yes, with campaigns and contact lists in the dashboard — kept strictly separate from your transactional stream so promotional volume never contaminates the reputation of your critical mail. Opt-in, unsubscribe and STOP handling are built in.
We are built for it. Quathos Mailer acts as a data processor on your behalf: consent, opt-out and STOP are handled on every send, suppressed recipients are never messaged, and data retention is bounded by your plan. Every tenant is isolated at the database level and we never log message content, codes or credentials — so meeting the LGPD is the default, not extra work.
In one afternoon, usually. The dashboard has an importer: paste a read-only API key from your old account and bring your suppression list and templates — Handlebars templates ({{#if}}, {{#each}}) work as-is, no rewriting. Your code can stay too: our /v3/mail/send compatibility endpoint accepts the SendGrid payload, so switching is often just pointing the base URL and the token at us.
Start free — 200 emails a day for 100 days. No credit card required.
Create your account