add-trigger

name	add-trigger
description	Create or update Sim webhook triggers using the generic trigger builder, service-specific setup instructions, outputs, and registry wiring. Use when working in `apps/sim/triggers/{service}/` or adding webhook support to an integration.

Add Trigger

You are an expert at creating webhook triggers for Sim. You understand the trigger system, the generic buildTriggerSubBlocks helper, and how triggers connect to blocks.

Your Task

1. Research what webhook events the service supports
2. Create the trigger files using the generic builder
3. Create a provider handler if custom auth, formatting, or subscriptions are needed
4. Register triggers and connect them to the block

Hard Rule: No Guessed Webhook Payload Schemas

If the service docs do not clearly show the webhook payload JSON for an event, you MUST tell the user instead of guessing trigger outputs or formatInput mappings.

• Do NOT invent payload field names
• Do NOT guess nested event object paths
• Do NOT infer output fields from the UI or marketing docs
• Do NOT write formatInput against unverified webhook bodies

If the payload shape is unknown, do one of these instead:

1. Ask the user for sample webhook payloads
2. Ask the user for a test webhook source so you can inspect a real event
3. Implement only the event registration/setup portions whose payloads are documented
4. Leave the trigger unimplemented and explicitly say which payload fields are unknown

Directory Structure

apps/sim/triggers/{service}/
├── index.ts              # Barrel exports
├── utils.ts              # Service-specific helpers (options, instructions, extra fields, outputs)
├── {event_a}.ts          # Primary trigger (includes dropdown)
├── {event_b}.ts          # Secondary trigger (no dropdown)
└── webhook.ts            # Generic webhook trigger (optional, for "all events")

apps/sim/lib/webhooks/
├── provider-subscription-utils.ts  # Shared subscription helpers (getProviderConfig, getNotificationUrl)
├── providers/
│   ├── {service}.ts       # Provider handler (auth, formatInput, matchEvent, subscriptions)
│   ├── types.ts           # WebhookProviderHandler interface
│   ├── utils.ts           # Shared helpers (createHmacVerifier, verifyTokenAuth, skipByEventTypes)
│   └── registry.ts        # Handler map + default handler

Step 1: Create utils.ts

This file contains all service-specific helpers used by triggers.

import type { SubBlockConfig } from '@/blocks/types'
import type { TriggerOutput } from '@/triggers/types'

export const {service}TriggerOptions = [
  { label: 'Event A', id: '{service}_event_a' },
  { label: 'Event B', id: '{service}_event_b' },
]

export function {service}SetupInstructions(eventType: string): string {
  const instructions = [
    'Copy the <strong>Webhook URL</strong> above',
    'Go to <strong>{Service} Settings > Webhooks</strong>',
    `Select the <strong>${eventType}</strong> event type`,
    'Paste the webhook URL and save',
    'Click "Save" above to activate your trigger',
  ]
  return instructions
    .map((instruction, index) =>
      `<div class="mb-3"><strong>${index + 1}.</strong> ${instruction}</div>`
    )
    .join('')
}

export function build{Service}ExtraFields(triggerId: string): SubBlockConfig[] {
  return [
    {
      id: 'projectId',
      title: 'Project ID (Optional)',
      type: 'short-input',
      placeholder: 'Leave empty for all projects',
      mode: 'trigger',
      condition: { field: 'selectedTriggerId', value: triggerId },
    },
  ]
}

export function build{Service}Outputs(): Record<string, TriggerOutput> {
  return {
    eventType: { type: 'string', description: 'The type of event' },
    resourceId: { type: 'string', description: 'ID of the affected resource' },
    resource: {
      id: { type: 'string', description: 'Resource ID' },
      name: { type: 'string', description: 'Resource name' },
    },
  }
}

Step 2: Create Trigger Files

Primary trigger — MUST include includeDropdown: true:

import { {Service}Icon } from '@/components/icons'
import { buildTriggerSubBlocks } from '@/triggers'
import { build{Service}ExtraFields, build{Service}Outputs, {service}SetupInstructions, {service}TriggerOptions } from '@/triggers/{service}/utils'
import type { TriggerConfig } from '@/triggers/types'

export const {service}EventATrigger: TriggerConfig = {
  id: '{service}_event_a',
  name: '{Service} Event A',
  provider: '{service}',
  description: 'Trigger workflow when Event A occurs',
  version: '1.0.0',
  icon: {Service}Icon,
  subBlocks: buildTriggerSubBlocks({
    triggerId: '{service}_event_a',
    triggerOptions: {service}TriggerOptions,
    includeDropdown: true,
    setupInstructions: {service}SetupInstructions('Event A'),
    extraFields: build{Service}ExtraFields('{service}_event_a'),
  }),
  outputs: build{Service}Outputs(),
  webhook: { method: 'POST', headers: { 'Content-Type': 'application/json' } },
}

Secondary triggers — NO includeDropdown (it's already in the primary):

export const {service}EventBTrigger: TriggerConfig = {
  // Same as above but: id: '{service}_event_b', no includeDropdown
}

Step 3: Register and Wire

apps/sim/triggers/{service}/index.ts

export { {service}EventATrigger } from './event_a'
export { {service}EventBTrigger } from './event_b'

apps/sim/triggers/registry.ts

import { {service}EventATrigger, {service}EventBTrigger } from '@/triggers/{service}'

export const TRIGGER_REGISTRY: TriggerRegistry = {
  // ... existing ...
  {service}_event_a: {service}EventATrigger,
  {service}_event_b: {service}EventBTrigger,
}

Block file (apps/sim/blocks/blocks/{service}.ts)

import { getTrigger } from '@/triggers'

export const {Service}Block: BlockConfig = {
  // ...
  triggers: {
    enabled: true,
    available: ['{service}_event_a', '{service}_event_b'],
  },
  subBlocks: [
    // Regular tool subBlocks first...
    ...getTrigger('{service}_event_a').subBlocks,
    ...getTrigger('{service}_event_b').subBlocks,
  ],
}

Provider Handler

All provider-specific webhook logic lives in a single handler file: apps/sim/lib/webhooks/providers/{service}.ts.

When to Create a Handler

Behavior	Method	Examples
HMAC signature auth	verifyAuth via createHmacVerifier	Ashby, Jira, Linear, Typeform
Custom token auth	verifyAuth via verifyTokenAuth	Generic, Google Forms
Event filtering	matchEvent	GitHub, Jira, Attio, HubSpot
Idempotency dedup	extractIdempotencyId	Slack, Stripe, Linear, Jira
Custom input formatting	formatInput	Slack, Teams, Attio, Ashby
Auto webhook creation	createSubscription	Ashby, Grain, Calendly, Airtable
Auto webhook deletion	deleteSubscription	Ashby, Grain, Calendly, Airtable
Challenge/verification	handleChallenge	Slack, WhatsApp, Teams
Custom success response	formatSuccessResponse	Slack, Twilio Voice, Teams

If none apply, you don't need a handler. The default handler provides bearer token auth.

Example Handler

import crypto from 'crypto'
import { createLogger } from '@sim/logger'
import { safeCompare } from '@/lib/core/security/encryption'
import type { EventMatchContext, FormatInputContext, FormatInputResult, WebhookProviderHandler } from '@/lib/webhooks/providers/types'
import { createHmacVerifier } from '@/lib/webhooks/providers/utils'

const logger = createLogger('WebhookProvider:{Service}')

function validate{Service}Signature(secret: string, signature: string, body: string): boolean {
  if (!secret || !signature || !body) return false
  const computed = crypto.createHmac('sha256', secret).update(body, 'utf8').digest('hex')
  return safeCompare(computed, signature)
}

export const {service}Handler: WebhookProviderHandler = {
  verifyAuth: createHmacVerifier({
    configKey: 'webhookSecret',
    headerName: 'X-{Service}-Signature',
    validateFn: validate{Service}Signature,
    providerLabel: '{Service}',
  }),

  async matchEvent({ body, requestId, providerConfig }: EventMatchContext) {
    const triggerId = providerConfig.triggerId as string | undefined
    if (triggerId && triggerId !== '{service}_webhook') {
      const { is{Service}EventMatch } = await import('@/triggers/{service}/utils')
      if (!is{Service}EventMatch(triggerId, body as Record<string, unknown>)) return false
    }
    return true
  },

  async formatInput({ body }: FormatInputContext): Promise<FormatInputResult> {
    const b = body as Record<string, unknown>
    return {
      input: {
        eventType: b.type,
        resourceId: (b.data as Record<string, unknown>)?.id || '',
        resource: b.data,
      },
    }
  },

  extractIdempotencyId(body: unknown) {
    const obj = body as Record<string, unknown>
    return obj.id && obj.type ? `${obj.type}:${obj.id}` : null
  },
}

Register the Handler

In apps/sim/lib/webhooks/providers/registry.ts:

import { {service}Handler } from '@/lib/webhooks/providers/{service}'

const PROVIDER_HANDLERS: Record<string, WebhookProviderHandler> = {
  // ... existing (alphabetical) ...
  {service}: {service}Handler,
}

Output Alignment (Critical)

There are two sources of truth that MUST be aligned:

1. Trigger outputs — schema defining what fields SHOULD be available (UI tag dropdown)
2. formatInput on the handler — implementation that transforms raw payload into actual data

If they differ: the tag dropdown shows fields that don't exist, or actual data has fields users can't discover.

Rules for formatInput:

• Return { input: { ... } } where inner keys match trigger outputs exactly
• Return { input: ..., skip: { message: '...' } } to skip execution
• No wrapper objects or duplication
• Use null for missing optional data

Automatic Webhook Registration

If the service API supports programmatic webhook creation, implement createSubscription and deleteSubscription on the handler. The orchestration layer calls these automatically — no code touches route.ts, provider-subscriptions.ts, or deploy.ts.

import { getNotificationUrl, getProviderConfig } from '@/lib/webhooks/provider-subscription-utils'
import type { DeleteSubscriptionContext, SubscriptionContext, SubscriptionResult } from '@/lib/webhooks/providers/types'

export const {service}Handler: WebhookProviderHandler = {
  async createSubscription(ctx: SubscriptionContext): Promise<SubscriptionResult | undefined> {
    const config = getProviderConfig(ctx.webhook)
    const apiKey = config.apiKey as string
    if (!apiKey) throw new Error('{Service} API Key is required.')

    const res = await fetch('https://api.{service}.com/webhooks', {
      method: 'POST',
      headers: { Authorization: `Bearer ${apiKey}`, 'Content-Type': 'application/json' },
      body: JSON.stringify({ url: getNotificationUrl(ctx.webhook) }),
    })

    if (!res.ok) throw new Error(`{Service} error: ${res.status}`)
    const { id } = (await res.json()) as { id: string }
    return { providerConfigUpdates: { externalId: id } }
  },

  async deleteSubscription(ctx: DeleteSubscriptionContext): Promise<void> {
    const config = getProviderConfig(ctx.webhook)
    const { apiKey, externalId } = config as { apiKey?: string; externalId?: string }
    if (!apiKey || !externalId) return
    await fetch(`https://api.{service}.com/webhooks/${externalId}`, {
      method: 'DELETE',
      headers: { Authorization: `Bearer ${apiKey}` },
    }).catch(() => {})
  },
}

Key points:

• Throw from createSubscription — orchestration rolls back the DB webhook
• Never throw from deleteSubscription — log non-fatally
• Return { providerConfigUpdates: { externalId } } — orchestration merges into providerConfig
• Add apiKey field to build{Service}ExtraFields with password: true

Trigger Outputs Schema

Trigger outputs use the same schema as block outputs (NOT tool outputs).

Supported: type + description for leaf fields, nested objects for complex data. NOT supported: optional: true, items (those are tool-output-only features).

export function buildOutputs(): Record<string, TriggerOutput> {
  return {
    eventType: { type: 'string', description: 'Event type' },
    timestamp: { type: 'string', description: 'When it occurred' },
    payload: { type: 'json', description: 'Full event payload' },
    resource: {
      id: { type: 'string', description: 'Resource ID' },
      name: { type: 'string', description: 'Resource name' },
    },
  }
}

Checklist

Trigger Definition

• Created utils.ts with options, instructions, extra fields, and output builders
• Primary trigger has includeDropdown: true; secondary triggers do NOT
• All triggers use buildTriggerSubBlocks helper
• Created index.ts barrel export

Registration

• All triggers in triggers/registry.ts → TRIGGER_REGISTRY
• Block has triggers.enabled: true and lists all trigger IDs in triggers.available
• Block spreads all trigger subBlocks: ...getTrigger('id').subBlocks

Provider Handler (if needed)

• Handler file at apps/sim/lib/webhooks/providers/{service}.ts
• Registered in providers/registry.ts (alphabetical)
• Signature validator is a private function inside the handler file
• formatInput output keys match trigger outputs exactly
• Event matching uses dynamic await import() for trigger utils

Auto Registration (if supported)

• createSubscription and deleteSubscription on the handler
• NO changes to route.ts, provider-subscriptions.ts, or deploy.ts
• API key field uses password: true

Testing

• bun run type-check passes
• Manually verify formatInput output keys match trigger outputs keys
• Trigger UI shows correctly in the block