diff --git a/apps/sim/lib/webhooks/provider-subscriptions.test.ts b/apps/sim/lib/webhooks/provider-subscriptions.test.ts
new file mode 100644
index 00000000000..beef3d4a62d
--- /dev/null
+++ b/apps/sim/lib/webhooks/provider-subscriptions.test.ts
@@ -0,0 +1,121 @@
+/**
+ * @vitest-environment node
+ */
+import type { NextRequest } from 'next/server'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+const { mockGetEffectiveDecryptedEnv, mockGetProviderHandler } = vi.hoisted(() => ({
+  mockGetEffectiveDecryptedEnv: vi.fn(),
+  mockGetProviderHandler: vi.fn(),
+}))
+
+vi.mock('@/lib/environment/utils', () => ({
+  getEffectiveDecryptedEnv: mockGetEffectiveDecryptedEnv,
+}))
+
+vi.mock('@/lib/webhooks/providers', () => ({
+  getProviderHandler: mockGetProviderHandler,
+}))
+
+import { createExternalWebhookSubscription } from '@/lib/webhooks/provider-subscriptions'
+
+describe('createExternalWebhookSubscription', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    mockGetEffectiveDecryptedEnv.mockResolvedValue({ ASHBY_API_KEY: 'real-secret-key' })
+  })
+
+  it('resolves {{ENV_VAR}} references in providerConfig before calling the provider', async () => {
+    const createSubscription = vi.fn().mockResolvedValue({
+      providerConfigUpdates: { externalId: 'ext-1' },
+    })
+    mockGetProviderHandler.mockReturnValue({ createSubscription })
+
+    const webhookData = {
+      provider: 'ashby',
+      providerConfig: { apiKey: '{{ASHBY_API_KEY}}', triggerId: 'ashby_application_submit' },
+    }
+    const workflow = { id: 'wf-1', workspaceId: 'ws-1' }
+
+    await createExternalWebhookSubscription(
+      {} as NextRequest,
+      webhookData,
+      workflow,
+      'user-1',
+      'req-1'
+    )
+
+    expect(mockGetEffectiveDecryptedEnv).toHaveBeenCalledWith('user-1', 'ws-1')
+    const passedWebhook = createSubscription.mock.calls[0][0].webhook
+    expect(passedWebhook.providerConfig.apiKey).toBe('real-secret-key')
+  })
+
+  it('persists the unresolved providerConfig, not the resolved one, back to the caller', async () => {
+    const createSubscription = vi.fn().mockResolvedValue({
+      providerConfigUpdates: { externalId: 'ext-1' },
+    })
+    mockGetProviderHandler.mockReturnValue({ createSubscription })
+
+    const webhookData = {
+      provider: 'ashby',
+      providerConfig: { apiKey: '{{ASHBY_API_KEY}}', triggerId: 'ashby_application_submit' },
+    }
+    const workflow = { id: 'wf-1', workspaceId: 'ws-1' }
+
+    const result = await createExternalWebhookSubscription(
+      {} as NextRequest,
+      webhookData,
+      workflow,
+      'user-1',
+      'req-1'
+    )
+
+    expect(result.updatedProviderConfig.apiKey).toBe('{{ASHBY_API_KEY}}')
+    expect(result.updatedProviderConfig.externalId).toBe('ext-1')
+  })
+
+  it('falls back to personal-only env resolution when workspaceId is not a string', async () => {
+    const createSubscription = vi.fn().mockResolvedValue({
+      providerConfigUpdates: { externalId: 'ext-1' },
+    })
+    mockGetProviderHandler.mockReturnValue({ createSubscription })
+
+    const webhookData = {
+      provider: 'ashby',
+      providerConfig: { apiKey: '{{ASHBY_API_KEY}}', triggerId: 'ashby_application_submit' },
+    }
+    const workflow = { id: 'wf-1', workspaceId: null }
+
+    await createExternalWebhookSubscription(
+      {} as NextRequest,
+      webhookData,
+      workflow,
+      'user-1',
+      'req-1'
+    )
+
+    expect(mockGetEffectiveDecryptedEnv).toHaveBeenCalledWith('user-1', undefined)
+  })
+
+  it('skips resolution and provider call entirely when the provider has no createSubscription', async () => {
+    mockGetProviderHandler.mockReturnValue({})
+
+    const webhookData = {
+      provider: 'slack',
+      providerConfig: { token: '{{SLACK_TOKEN}}' },
+    }
+    const workflow = { id: 'wf-1', workspaceId: 'ws-1' }
+
+    const result = await createExternalWebhookSubscription(
+      {} as NextRequest,
+      webhookData,
+      workflow,
+      'user-1',
+      'req-1'
+    )
+
+    expect(mockGetEffectiveDecryptedEnv).not.toHaveBeenCalled()
+    expect(result.externalSubscriptionCreated).toBe(false)
+    expect(result.updatedProviderConfig.token).toBe('{{SLACK_TOKEN}}')
+  })
+})
diff --git a/apps/sim/lib/webhooks/provider-subscriptions.ts b/apps/sim/lib/webhooks/provider-subscriptions.ts
index ae8b160279e..afd9a926648 100644
--- a/apps/sim/lib/webhooks/provider-subscriptions.ts
+++ b/apps/sim/lib/webhooks/provider-subscriptions.ts
@@ -1,6 +1,7 @@
 import { createLogger } from '@sim/logger'
 import { toError } from '@sim/utils/errors'
 import type { NextRequest } from 'next/server'
+import { resolveWebhookProviderConfig } from '@/lib/webhooks/env-resolver'
 import { getProviderHandler } from '@/lib/webhooks/providers'
 
 const logger = createLogger('WebhookProviderSubscriptions')
@@ -88,6 +89,14 @@ export function shouldRecreateExternalWebhookSubscription({
  * Ask the provider handler to create an external webhook subscription, if that
  * provider supports automatic registration.
  *
+ * `providerConfig` may contain unresolved `{{ENV_VAR}}` references (e.g. an
+ * API key field backed by an environment variable) — these are resolved here
+ * before the provider call so deploy-triggered registration (this function is
+ * also called from the async deployment outbox, not just the interactive
+ * webhook-save route) behaves the same as a manual save. The persisted
+ * `providerConfig` returned to the caller stays unresolved; only the
+ * provider-managed fields from `result.providerConfigUpdates` get merged in.
+ *
  * The returned provider-managed fields are merged back into `providerConfig`
  * by the caller.
  */
@@ -106,8 +115,16 @@ export async function createExternalWebhookSubscription(
     return { updatedProviderConfig: providerConfig, externalSubscriptionCreated: false }
   }
 
+  const workspaceId = typeof workflow.workspaceId === 'string' ? workflow.workspaceId : undefined
+
+  const resolvedProviderConfig = await resolveWebhookProviderConfig(
+    providerConfig,
+    userId,
+    workspaceId
+  )
+
   const result = await handler.createSubscription({
-    webhook: webhookData,
+    webhook: { ...webhookData, providerConfig: resolvedProviderConfig },
     workflow,
     userId,
     requestId,