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Cloud API

The Cloud API is the server-side interface to Unlayer. It runs outside the browser and lets your backend:

  • Send transactional email from your own verified domains, with delivery tracking, webhooks, and suppression handling
  • Generate artifacts (HTML, PDF, Image, ZIP) from a design JSON
  • Manage templates stored in your Unlayer project
  • List blocks — shared and end-user saved — for backup and usage reporting
  • Convert designs between Full and Simple schema forms
  • Validate a design against the Unlayer schema
  • Execute secure operations that should not run in the browser

View the full API reference →

When to use the Cloud API​

Reach for the Cloud API when:

  • You want to send transactional email (welcome, receipts, password resets) from your own domain without running your own SMTP/ESP integration
  • You need to generate a PDF from a design in a background job
  • You want to export HTML without exposing API keys to the browser
  • You want to generate an image preview server-side
  • You are running a cron job, webhook handler, or worker process
  • You need to validate or convert a design payload before storing or rendering it
Embedding the builder?

If your use case involves embedding a visual builder or editor in your frontend, see Builders instead.

How it works​

Most server workflows follow this pattern:

Server workflow: design JSON from browser to backend; Cloud API returns artifact

  1. A Builder produces a design JSON (in the browser).
  2. Your backend sends that JSON to the Cloud API.
  3. The API returns a generated artifact (HTML, PDF, Image, ZIP) — or a validated / converted design payload.
  4. You store, send, or distribute the result.
Exporting HTML

For HTML export, you often don't need the Cloud API — the builder can produce HTML directly in the browser via unlayer.exportHtml(). Use the Cloud API when you need to export HTML server-side (for example, in a background job or when the user is not in the builder).

Sending email​

Send transactional email from a verified domain using raw HTML or a saved template. Email Sending is in private beta and requires workspace access.

Use POST /v3/emails for HTML or POST /v3/emails/template for a template. A new accepted send returns 202 and an email ID. Track delivery with webhooks or the email detail endpoint, and use an Idempotency-Key when retrying a request.

See the Email Sending guide for authentication, domain verification, limits, and complete examples.

Security model​

The Cloud API uses bearer-token authentication — API Key, Personal Access Token, or OAuth. See Authentication for token types, how to get each one from Console, and security guidelines.

Keep tokens server-side

Tokens grant full access to your project's data:

  • Never call the Cloud API directly from the browser
  • Always proxy requests through your backend
  • Keep tokens in secure server-side environments only

Typical use cases​

Use caseDescription
Send transactional emailDeliver receipts, password resets, and notifications from your verified domain via POST /v3/emails.
Export PDF in background jobGenerate a PDF after a user submits a form, then email it automatically.
Generate HTML for email sendingExport HTML server-side and send it via the Send API — or pass it to your own email provider.
Image thumbnail generationGenerate preview images for templates or documents.
ZIP export for asset bundlesProduce downloadable packages including images and required assets.
Validate user-supplied designsCheck that an imported or uploaded design conforms to the schema.
Convert between schema formsRound-trip designs between the editor's Full shape and the wire Simple shape.

What's next​

  • See the API reference for the full endpoint list.
  • See Design Schema for the shape of the design JSON the API accepts and returns.
  • If you're embedding the builder, go to Builders.