Templates

A template holds the content of a message in one or more locales.

{
  "key": "payment-due",
  "default_locale": "en",
  "locales": {
    "en": {
      "title": "Payment due {{ data.due_date }}",
      "body": "{{ data.amount | number }} {{ data.currency }} is due. Tap to pay.",
      "url": "myapp://invoices/{{ data.invoice_id }}",
      "image_url": null,
      "data": {"screen": "invoice", "invoice_id": "{{ data.invoice_id }}"},
      "channels": {
        "sms": {"body": "{{ data.amount | number }} {{ data.currency }} due {{ data.due_date }}."},
        "email": {"html": "<p>Your invoice <b>{{ data.invoice_id }}</b> is due.</p>"}
      }
    },
    "ru": {"title": "…", "body": "…"}
  },
  "ai_instructions": null,
  "ai_attributes": []
}

Fields

Field	Used by
title	Push title, e-mail subject, bold first line in Telegram.
body	Every channel.
url	Deep link: push data.url, appended to SMS/Telegram, link in e-mail text.
image_url	Push notification image.
thread	Groups related messages on the device: APNs thread-id, FCM data.thread, an e-mail References header, forwarded by webhooks. See digests.
html	E-mail HTML part (auto-escaped).
data	Push data payload / webhook payload. Values are templates too.
actions	Up to four buttons (id, label, url); see importance and expiry.
channels	Per-channel overrides. Unset fields inherit from the locale's base content.

Variables

Variable	Contents
data	The event's data, the broadcast's variables, or the direct send's data.
recipient	external_id, locale, timezone, attributes.
event	name, source, occurred_at — null for direct sends and broadcasts.
category	The message category key.
importance	low, normal, high or critical.
links	preferences and unsubscribe URLs and the preference token — see preference centre.

Filters: everything Jinja2 provides plus number(decimals=0, separator=" ", point=".") for thousands separators: {{ 1250000 | number }} → 1 250 000.

Safety and strictness

• Templates run in Jinja's immutable sandbox: no access to Python internals, no mutation of data.
• Undefined variables are errors, not empty strings. A message that would read "Your order has shipped" fails with status_reason: template_error: … instead. Use {{ data.name | default("there") }} for optional values.
• Syntax is checked when the template is saved.
• html is auto-escaped; other fields are plain text.
• Resource limits stop runaway templates: range() is capped at 1 000 items, powers at an exponent of 64, sequence repetition at 10 000 items, center/indent widths at 200 and each rendered field at 20 000 characters. Python string formatting (%, .format, the format filter) is disabled — use ~ to concatenate.

Locale selection

For a recipient with locale uz-Latn-UZ, Cue tries uz-latn-uz, uz-latn, uz, then the template's default_locale, then any available locale. Matching is case-insensitive and treats _ like -.

Versions and previews

Every content change increments version; messages record the template version they were rendered from. POST /v1/templates/{key}/preview renders all variants with sample data (and optionally a real recipient) without sending anything.