> ## Documentation Index > Fetch the complete documentation index at: https://docs.tetherai.ca/llms.txt > Use this file to discover all available pages before exploring further. # Handle Outlook (Microsoft Graph) change notification > Inbound webhook called by Microsoft Graph when a subscribed mailbox receives a new message. On subscription creation Graph performs a validation handshake by sending a `validationToken` query parameter, which the endpoint echoes back as plain text. Notification payloads are accepted with 202 and processed asynchronously. ## OpenAPI ````yaml /api-reference/openapi.yaml post /api/webhook/email/outlook openapi: 3.0.3 info: title: Tether Relay and Tether API version: 1.0.0 description: >- Route-derived OpenAPI contract generated from tether-relay backend sources. Regenerate with scripts/sync-openapi-from-backend.mjs. servers: - url: https://your-instance.example.com description: Production - url: http://localhost:2212 description: Local API service security: [] tags: - name: AI - name: Applications - name: Approval - name: Auth - name: Automations - name: Calls - name: Campaigns - name: Contact Analytics - name: Contact Metrics - name: Contact Notes - name: Contacts - name: Conversation Monitor - name: Conversations - name: Departments - name: Email - name: Escalation Dashboard - name: Event Logs - name: Google Sheets - name: Marketplace - name: Messages - name: Notification Sounds - name: Notifications - name: Org Snapshots - name: Organizations - name: Outreach - name: Outreach Metrics - name: Outreach Sources - name: Pipelines - name: Processes - name: Prompts - name: Reminders - name: Sms - name: Templates - name: Traces - name: Training - name: Upload - name: User Snapshots - name: Users - name: Vertical - name: Webchats - name: Webhook paths: /api/webhook/email/outlook: post: tags: - Webhooks summary: Handle Outlook (Microsoft Graph) change notification description: >- Inbound webhook called by Microsoft Graph when a subscribed mailbox receives a new message. On subscription creation Graph performs a validation handshake by sending a `validationToken` query parameter, which the endpoint echoes back as plain text. Notification payloads are accepted with 202 and processed asynchronously. operationId: post_webhook_email_outlook parameters: - in: query name: validationToken required: false schema: type: string description: >- Sent by Microsoft Graph during subscription validation. When present the endpoint echoes it back as text/plain and skips notification processing. requestBody: required: false content: application/json: schema: $ref: '#/components/schemas/OutlookWebhookRequest' responses: '200': description: >- Validation handshake — the supplied `validationToken` is echoed back as plain text. content: text/plain: schema: type: string example: A1B2C3D4-E5F6-7890-ABCD-EF1234567890 '202': description: >- Notification accepted for async processing. Body is the literal text `Accepted`. content: text/plain: schema: type: string example: Accepted '500': description: Webhook processing failed content: application/json: schema: $ref: '#/components/schemas/WebhookErrorResponse' components: schemas: OutlookWebhookRequest: type: object description: Microsoft Graph change notification batch. properties: value: description: >- Array of change notifications Microsoft Graph batches into one request. type: array items: type: object properties: subscriptionId: type: string description: >- Graph subscription this notification originates from; maps to the Tether mailbox connection. subscriptionExpirationDateTime: type: string description: >- ISO-8601 timestamp when the Graph subscription expires — used to trigger renewal. changeType: type: string description: Type of change, e.g. `created`, `updated`, `deleted`. resource: type: string description: >- Graph resource path for the changed item (e.g. `Users/{id}/Messages/{id}`). resourceData: description: >- Lightweight pointer to the changed entity (id + @odata.type); the full message is fetched separately via Graph. type: object additionalProperties: true clientState: type: string description: >- Opaque token supplied at subscription time and echoed back to verify the notification is genuine. tenantId: type: string description: Azure AD tenant id the mailbox belongs to. additionalProperties: true additionalProperties: true example: value: - subscriptionId: 7f4b2c1d-9e0a-4b3c-8d5e-6f7a8b9c0d1e subscriptionExpirationDateTime: '2026-05-20T15:04:01.135Z' changeType: created resource: Users/ops@acme.example/Messages/AAMkAGI2T..== resourceData: '@odata.type': '#Microsoft.Graph.Message' '@odata.id': Users/ops@acme.example/Messages/AAMkAGI2T..== id: AAMkAGI2T..== clientState: tether-outlook-secret tenantId: 5f7b1c2e-8a1d-4e00-12c3-b4a55f7b1c2e WebhookErrorResponse: type: object description: >- Error envelope used across provider webhook routes. Most failures only carry `error`; a few (ElevenLabs tool errors, ingress validation) add `success:false`, `message`, or a `code`. Many of these endpoints respond 200 with `success:false` for recoverable cases (especially the ElevenLabs server tools) — only hard failures use 4xx/5xx. properties: error: type: string message: type: string success: type: boolean enum: - false code: type: string details: description: Optional diagnostic detail (stack snippet, validation issues, etc.). additionalProperties: true example: error: Webhook processing failed ````