> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sequenzy.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Render Campaign HTML
> Render a campaign to email-ready HTML for an embedded preview
Render a campaign to the exact email-safe HTML that would be sent. Use this to show a visual preview inside your own dashboard or email builder without duplicating Sequenzy's rendering logic.
The render applies everything the send path applies: your email theme and font, company branding and footer, localization, block visibility conditions, product recommendation blocks, and merge tags.
This endpoint is read-only. It requires the `campaigns:read` scope and never
sends, schedules, or modifies anything. It uses `POST` only so personalization
input can travel in a request body.
## Request
Campaign ID.
Personalize as this stored subscriber. Use this or `subscriber`, not both.
Because the rendered HTML then carries that subscriber's details, this field
also requires the `subscribers:read` scope.
Personalize as an ad-hoc contact that does not need to exist in your account.
Accepts `email` (required), `firstName`, `lastName`, and `customAttributes`.
Use this or `subscriberId`, not both.
Extra merge variables layered over the contact's attributes.
Force a localization locale instead of deriving it from the contact.
Render a specific A/B test variant of this campaign.
Apply your company's auto-UTM link decoration, as a real send would. Defaults
to `false` so the preview shows your own clean URLs.
```bash theme={null}
curl -X POST "https://api.sequenzy.com/api/v1/campaigns/camp_abc123/render" \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"subscriber": {
"email": "anna@example.com",
"firstName": "Anna"
},
"variables": { "plan": "Pro" },
"tracking": false
}'
```
## Personalization
Without `subscriberId` or `subscriber`, the campaign renders for a sample contact and merge tags resolve to empty values. The response's `personalized` field tells you which happened.
Only a stored subscriber (`subscriberId`) can resolve subscriber-scoped content: block visibility conditions, product recommendations, and a working unsubscribe link. An inline `subscriber` covers name and attribute merge tags.
Passing `subscriberId` puts that subscriber's data into the returned HTML, so it needs the `subscribers:read` scope on top of `campaigns:read`. Rendering for a sample contact or an inline `subscriber` needs only `campaigns:read`.
## What is not in the HTML
Per-send click-redirect wrapping, the open tracking pixel, and unsubscribe click tracking are applied at send time against a real email send record. A preview has no such record, so those are never present in the returned HTML - emitting placeholder versions would give you URLs that 404. The `tracking` flag therefore controls auto-UTM decoration only, which is genuinely applied at render time.
## Responses
```json 200 theme={null}
{
"success": true,
"html": "...",
"subject": "Anna, your Pro plan is ready",
"previewText": "Everything you unlocked this month",
"locale": "en",
"personalized": true,
"trackingApplied": false,
"entity": {
"type": "campaign",
"id": "camp_abc123",
"variantId": null
}
}
```
```json 400 theme={null}
{
"error": "Provide either subscriberId or subscriber, not both."
}
```
```json 401 theme={null}
{
"error": "Unauthorized"
}
```
```json 403 theme={null}
{
"error": "API key is missing required scope: subscribers:read"
}
```
```json 404 theme={null}
{
"error": "Campaign not found"
}
```