Email templating & automation

Every email your product sends, crafted in one place.

Coldletter is the design and automation layer that sits on top of SendGrid, Postmark, and Amazon SES. Build templates visually, version them like code, automate the journeys — and let your provider handle the sending.

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app.coldletter.com/templates/welcome
Workspace
Templates
Journeys
Analytics
Templates
Welcome
Password reset
Receipt
Win-back
Welcome · v12
Block · Headline
Hi {{first_name}}…
Variables
first_name string
plan_name string
cta_url url

Sends through your stack — not around it

SendGrid Postmark Amazon SES Mailgun Resend SparkPost

Visual editor

Design email like a document, ship it like code.

Drag blocks, drop in variables, and preview across clients in real time. Every template is responsive, accessible, and dark-mode-safe by default — no MJML wrangling, no table soup.

  • Reusable blocks & partials. Build a header once, reuse it across every template in the workspace.
  • Typed variables. Define {{first_name}} as a string, {{cart}} as a list — catch missing data before send.
  • Inbox-ready preview. See exactly how it renders in Gmail, Outlook, and Apple Mail — light and dark.
Live preview · Gmail · dark

Automation

Automate the journey, not just the send.

Compose triggers, waits, branches, and sends on a visual canvas. Coldletter decides who gets what and when — then hands the actual delivery to your provider over a single API.

  • Event & schedule triggers. Fire on a webhook, an API event, or a fixed cadence.
  • Branch on anything. Split paths by attribute, engagement, or A/B allocation.

Welcome journey

User signs up
trigger · event
Send “Welcome”
template · v12
Wait 2 days
delay

Opened welcome?

No
send nudge
Yes
exit journey

Everything in the workspace

Built for teams who treat email seriously.

Version control

Every change is a commit. Diff templates, roll back instantly, and ship with confidence.

A/B testing

Pit subject lines and layouts against each other, then auto-promote the winner.

Localization

Translate once, send everywhere. Per-locale variants resolve automatically at send time.

Test sends & preview

Fire a real send to yourself with sample data before a single customer sees it.

Delivery analytics

Opens, clicks, bounces, and deliverability — unified across every provider you use.

Roles & approvals

Draft, review, approve. Lock production templates behind sign-off from the right people.

For developers

One call to send. We handle the rest.

Trigger any template with a single API request. Coldletter merges your data, renders the template, picks the route, and dispatches through your configured provider — with retries, suppression, and idempotency built in.

send.ts
// trigger a template — provider chosen for you
await coldletter.send({
  template: "welcome",
  to: "[email protected]",
  data: {
    first_name: "Maya",
    plan_name: "Growth",
    cta_url: "https://app.northwind.co"
  },
  route: "sendgrid"   // or postmark, ses…
});

// → 202 queued · id: msg_8fK2…
Why teams switch

“We deleted three internal tools and a folder of MJML hacks. Now design owns the templates, engineering owns one API call, and nothing breaks on send.

Maya Okonkwo
Head of Lifecycle, Northwind
±0.
Tables hand-coded. Coldletter renders responsive, dark-mode-safe HTML for you.
6+
Provider backends supported — switch routes without touching a template.
99.9%
Render uptime, with idempotent sends and automatic retries.

Start today

Precision and craft for every email you send.

Connect your provider, import a template, and ship your first automated send before lunch.