> ## Documentation Index > Fetch the complete documentation index at: https://docs.ohmyho.st/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > For account actions, read https://ohmyho.st/skills/ohmyhost-get-started/SKILL.md and use the authenticated ohmyho.st CLI or local product MCP. Mintlify search only reads documentation. Preserve the customer’s selected project, environment and authentication provider. # Prepare a required customer webhook and return its signing secret > One production mail domain per project; environment_id is the project Prod environment ID. Dev and Prod application URLs do not create separate mail domains. Provider credentials never leave ohmyho.st. Content expires 72 hours after original receipt. ## OpenAPI ````yaml /openapi.json put /v1/projects/{project_id}/environments/{environment_id}/mail-webhook openapi: 3.1.2 info: title: ohmyho.st API version: 0.0.0 description: >- Public REST API for ohmyho.st hosting, projects, domains, email, credits and exports. servers: - url: https://app.ohmyho.st description: Production control API - url: https://dev.app.ohmyho.st description: Development control API security: - BearerAuth: [] paths: /v1/projects/{project_id}/environments/{environment_id}/mail-webhook: put: summary: Prepare a required customer webhook and return its signing secret description: >- One production mail domain per project; environment_id is the project Prod environment ID. Dev and Prod application URLs do not create separate mail domains. Provider credentials never leave ohmyho.st. Content expires 72 hours after original receipt. operationId: prepareManagedMailWebhook parameters: - $ref: '#/components/parameters/RequestId' - $ref: '#/components/parameters/IdempotencyKey' - name: project_id in: path required: true schema: $ref: '#/components/schemas/Ulid' - name: environment_id in: path required: true schema: $ref: '#/components/schemas/Ulid' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/ManagedMailWebhookRequest' responses: '200': description: Authorized mail result. content: application/json: schema: $ref: '#/components/schemas/ManagedMailWebhook' '400': $ref: '#/components/responses/Problem' '401': $ref: '#/components/responses/Problem' '403': $ref: '#/components/responses/Problem' '404': $ref: '#/components/responses/Problem' '409': $ref: '#/components/responses/Problem' '429': $ref: '#/components/responses/Problem' '503': $ref: '#/components/responses/Problem' components: parameters: RequestId: name: X-Request-Id in: header description: Optional caller-provided correlation identifier. required: false schema: type: string minLength: 1 maxLength: 128 IdempotencyKey: name: Idempotency-Key in: header description: Identifies one mutation and its canonical request payload. required: true schema: type: string minLength: 1 maxLength: 128 schemas: Ulid: type: string pattern: ^[0-9A-HJKMNP-TV-Z]{26}$ ManagedMailWebhookRequest: type: object additionalProperties: false required: - url properties: url: type: string format: uri maxLength: 2048 ManagedMailWebhook: type: object additionalProperties: false required: - url - signing_secret - status properties: url: type: string format: uri signing_secret: type: string description: Server-only signing secret. Never log or send it to the browser. status: type: string const: verification_required ProblemDetails: type: object description: RFC 9457 Problem Details extended with stable ohmyhost recovery fields. additionalProperties: false required: - type - title - status - code - request_id - retryable - suggested_action properties: type: type: string format: uri-reference title: type: string minLength: 1 status: type: integer minimum: 400 maximum: 599 detail: type: string instance: type: string format: uri-reference code: type: string enum: - invalid_request - unauthenticated - forbidden - organization_required - resource_not_found - idempotency_key_reused - project_handle_unavailable - project_identity_unavailable - deployment_plan_expired - deployment_plan_incompatible - confirmation_expired - confirmation_invalid - etag_mismatch - promotion_source_stale - promotion_target_stale - promotion_invalid_target - mail_domain_conflict - mail_domain_required - storage_jurisdiction_conflict - shared_data_requires_promotion - framework_conversion_required - repository_configuration_missing - migration_filename_noncanonical - environment_secret_mutation_blocked - workers_runtime_incompatible - project_handle_invalid - project_handle_taken - project_handle_unchanged - project_rename_blocked - payload_too_large - rate_limited - insufficient_organization_credits - paid_plan_required - project_budget_exceeded - compute_performance_paid_required - compute_performance_unavailable - database_write_pending - database_access_limit - compute_change_pending - compute_change_conflict - billing_purchase_conflict - billing_recharge_conflict - github_connection_required - github_connection_revoked - repository_not_installed - cloudflare_zone_not_bound - cloudflare_authorization_closed - project_notes_conflict - project_export_not_ready - interactive_login_required - api_key_creation_uncertain - api_key_permissions_unavailable - reconciliation_exhausted - service_unavailable request_id: type: string minLength: 1 maxLength: 128 retryable: type: boolean retry_after_seconds: type: integer minimum: 1 maximum: 86400 description: >- Optional machine-readable retry delay for a rate limit, matching Retry-After. suggested_action: type: string minLength: 1 responses: Problem: description: The request failed. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' headers: XRequestId: description: Correlates the request with operations, events, logs, and audit records. required: true schema: type: string minLength: 1 maxLength: 128 securitySchemes: BearerAuth: type: http scheme: bearer description: >- WorkOS access JWT or a user-owned WorkOS API key. User keys are bound to one organization and restricted to their enabled product permissions. Session-only onboarding and session revocation require an interactive access JWT. No cookie session is assumed. ````