> ## Documentation Index > Fetch the complete documentation index at: https://docs.zivio.com/llms.txt > Use this file to discover all available pages before exploring further. # Cancel a project (with a reason) > Cancels the project via the same interactor as the web UI: live milestones are cancelled, open proposals are eliminated (their suppliers are notified), outstanding tasks are cancelled, and the reason is recorded. A reason is required: `reason_code_id` when the tenant has cancellation reason codes configured, otherwise `cancellation_reason_id` (optionally with `cancellation_other_reason`). If the reason is missing or invalid the 422 response lists the valid options — re-submit with one of them. Idempotent: cancelling an already-cancelled project reports `changed: false` without re-notifying. ## OpenAPI ````yaml /api-reference/v4/openapi.json post /projects/{id}/cancel openapi: 3.1.0 info: title: API V4 version: '4' description: >- OAuth 2.0 secured API. Obtain an access token using client credentials to access protected endpoints. The regional endpoints listed below serve every Zivio organisation, so each request — including the token request — must carry a `zivio-tenant-id` header identifying yours. Requests without it are rejected with a 404 before any token is checked. contact: name: API Support email: support@zivio.com servers: - url: https://api.zivio.net/api/v4 description: Global API Router - url: https://api.eu.zivio.net/api/v4 description: EU Data Region - url: https://api.uk.zivio.net/api/v4 description: UK Data Region - url: https://api.us.zivio.net/api/v4 description: US Data Region security: - oauth2: [] tenantId: [] paths: /projects/{id}/cancel: post: tags: - Projects summary: Cancel a project (with a reason) description: >- Cancels the project via the same interactor as the web UI: live milestones are cancelled, open proposals are eliminated (their suppliers are notified), outstanding tasks are cancelled, and the reason is recorded. A reason is required: `reason_code_id` when the tenant has cancellation reason codes configured, otherwise `cancellation_reason_id` (optionally with `cancellation_other_reason`). If the reason is missing or invalid the 422 response lists the valid options — re-submit with one of them. Idempotent: cancelling an already-cancelled project reports `changed: false` without re-notifying. operationId: postProjectsByIdCancel parameters: - name: id in: path required: true schema: type: integer description: Project ID example: 123 requestBody: required: false content: application/json: schema: type: object properties: reason_code_id: type: integer description: >- A cancellation reason code id (tenants with reason codes configured). The 422 response lists the valid codes. example: 12 custom_reason: type: string description: Free-text detail accompanying the reason code. example: The requirement has been withdrawn by the budget owner. cancellation_reason_id: type: integer description: >- A cancellation reason id (tenants without reason codes). The 422 response lists the valid reasons. example: 3 cancellation_other_reason: type: string description: Free-text reason, used with the "other" cancellation reason. example: Duplicate of an existing engagement. responses: '200': description: >- The project state after the call, with how many open proposals were eliminated content: application/json: schema: type: object example: project_id: 123 project_title: Website Redesign state: cancelled changed: true message: Project 123 cancelled eliminated_proposals: 2 '401': description: >- Unauthorized - the access token is missing, expired, revoked or malformed content: application/json: schema: $ref: '#/components/schemas/Error' example: error: invalid_token error_description: >- The access token provided is expired, revoked, malformed, or invalid for other reasons '403': description: Forbidden - insufficient scope content: application/json: schema: $ref: '#/components/schemas/Error' example: error: insufficient_scope error_description: >- The request requires higher privileges than provided by the access token required_scope: projects:write provided_scopes: - welcome:read '422': description: >- Missing/invalid reason (response lists valid options), or state not cancellable content: application/json: schema: type: object example: error: reason_required message: >- Please provide a reason for cancellation (reason_code_id is required) reason_codes: - id: 12 label: Requirement withdrawn security: - oauth2: - projects:write tenantId: [] components: schemas: Error: type: object description: Error envelope returned by every non-2xx V4 response properties: error: type: string example: insufficient_scope error_description: type: string message: type: string details: type: object additionalProperties: true required_scope: type: string example: projects:read provided_scopes: type: array items: type: string securitySchemes: oauth2: type: oauth2 description: >- OAuth 2.0 client credentials. The access token from POST /oauth/token is sent as a bearer token. Request only the scopes you need. flows: clientCredentials: tokenUrl: https://api.zivio.net/api/v4/oauth/token scopes: bank_accounts:read: Read bank account details on suppliers and the org. catalogs:read: Read catalog items. cost_centers:read: Read cost center records. eoi_responses:read: Read responses to expressions of interest. eois:read: Read expressions of interest. offers:read: Read offers for projects. org_units:read: Read your organization unit hierarchy. org_users:read: Read members of your organization. resources:read: Read resource (worker) records. sales_invoices:read: Read invoices issued to clients. sales_milestones:read: Read milestones on sales engagements. skill_categories:read: Read the skill category taxonomy. skill_taxonomies:read: Read skill taxonomy structure. skills:read: Read individual skills. supplier_documents:read: Read documents uploaded by suppliers. supplier_lists:read: Read curated lists of suppliers. supplier_users:read: Read users belonging to supplier organizations. tax_types:read: Read configured tax types. users:read: Read user profiles. variation_orders:read: Read variation orders on projects. welcome:read: 'Required: confirms your identity to the application.' bid_evaluations:read: >- Read evaluation scorecards for bids, including criterion scores and quality, cost and total scores. bid_evaluations:write: >- Score bids against a project's quality criteria and override calculated cost scores. bids:read: Read bids submitted on projects. bids:write: >- Shortlist, select, eliminate and reinstate bids submitted on projects. invoices:read: Read invoices on projects. invoices:write: Create and update invoices. notes:read: Read notes on projects and EOIs. notes:write: Create and update notes on projects and EOIs. project_approvals:read: Read project approval workflows. project_approvals:write: Create and update project approval workflows. project_conversations:read: Read messages exchanged with suppliers on a project. project_conversations:write: Send messages to suppliers on a project. project_invitations:read: Read supplier invitations on projects. project_invitations:write: Invite suppliers to bid on projects. project_questions:read: Read supplier clarification questions on projects. project_questions:write: Answer and approve supplier clarification questions. projects:read: Read projects. projects:write: Create and update projects. milestones:read: Read milestones on projects. milestones:write: Create and update milestones. orgs:read: Read organization records. orgs:write: Create and update organization records. purchase_orders:read: Read purchase orders. purchase_orders:write: Create and update purchase orders. reviews:read: Read reviews left on suppliers. reviews:write: Create and update reviews. suppliers:read: Read supplier profiles. suppliers:write: Create and update supplier profiles. raw_scorecard_entries:write: Create and update raw scorecard entries. raw_scorecard_entries:read: Read raw scorecard entries. tasks:read: >- Read the acting user's task queue, including outstanding approvals and items to review. tasks:write: Complete and dismiss tasks in the acting user's task queue. act_as_user: >- Make requests as another user within the token holder's delegation boundary. tenantId: type: apiKey name: zivio-tenant-id in: header description: >- Your Zivio organisation identifier. The regional API endpoints serve every Zivio organisation, so each request must identify yours. ````