Triggers

Trigger config is persisted per function/kind and controls how runtime invocation is initiated.

Step-by-Step Guide

1.Trigger schema

Each function keeps at most one row per trigger kind (fnId + kind).

http: { requireAuth: boolean } (defaults to false for new functions)
cron: { schedule: string, timezone?: string }
email: { address: string, allowlist?: string[] } — address is platform-generated as {fn}-{workspace}-{random}@… and can be regenerated at any time
mcp: { toolName: string, description: string }

2.HTTP trigger

HTTP entrypoint is runtime route /run/:orgSlug/:fnSlug.

HTTP is created automatically for new functions.
When requireAuth is true, send Authorization: Bearer <workspace API token> (see Settings → Tokens).
Nested calls from executeFunction send x-hostfunc-parent-exec and skip the API token when the parent execution is valid.

3.Cron trigger

Cron worker fetches due jobs from control plane and invokes runtime with cron trigger metadata.

Due/ack flow is handled by internal cron endpoints.
Runtime receives hostfuncTriggerKind: "cron" over an authenticated internal invoke.

4.Email trigger

Every function can have one generated inbound address. Mail sent to it invokes your exported email(data) handler with the payload shape below.

Address format: {function-slug}-{workspace-slug}-{random}@hostfunc.io (slugs truncated to 20 chars, 8-char random suffix).
If the function has an active custom domain with verified inbound email, new addresses are generated on that domain instead — see Custom Domains → Receive email on your domain.
Regenerating replaces the address in place: the old address stops matching immediately.
Optional sender allowlist — empty accepts mail from anyone; otherwise only listed senders trigger the function (case-insensitive).
User code exports export async function email(data); data.email includes to, from, rawSize, timestamp (ISO 8601), and optional subject / body.
Local development is fully mocked: the dispatch payload is logged to the dev server console, and a dev-only "Send test email" button on the triggers page exercises the whole path without DNS or a mail provider.

typescript

export async function email(data: {  email: {    from: string;    to: string;    rawSize: number;    timestamp: string;    subject?: string;    body?: string;  };}) {  return { received: data.email.subject ?? "(no subject)" };}

5.MCP-related triggering

MCP tool calls execute through /api/mcp handlers and are audited.