--- updatedAt: 2026-05-07T21:22:44.000Z agentTools: projectIndex: https://developer.firmcheck.com/llms.txt --- # Create a related party Add a related party to this organisation. The `existing` arm links one Firmcheck already holds; the other arms create a new individual or organisation. # OpenAPI definition ```json { "openapi": "3.0.2", "paths": { "/organisations/{organisationId}/related-parties": { "post": { "description": "Add a related party to this organisation. The `existing` arm links one Firmcheck already holds; the other arms create a new individual or organisation.", "summary": "Create a related party", "tags": [ "Organisations" ], "parameters": [ { "name": "organisationId", "in": "path", "required": true, "schema": { "type": "string" }, "description": "The unique identifier for the organisation." }, { "name": "accept-version", "in": "header", "required": true, "schema": { "type": "string", "enum": [ "1.0.0" ] } } ], "operationId": "createRelatedParty", "requestBody": { "description": "Body", "content": { "application/json": { "schema": { "oneOf": [ { "type": "object", "properties": { "object": { "type": "string", "enum": [ "individual" ] }, "firstName": { "type": "string", "description": "The first name of the individual." }, "middleName": { "type": "string", "description": "The middle name of the individual." }, "lastName": { "type": "string", "description": "The last name of the individual." }, "email": { "type": "string", "description": "The email address of the individual." }, "residentialAddress": { "type": "object", "properties": { "line1": { "type": "string", "nullable": true }, "line2": { "type": "string", "nullable": true }, "city": { "type": "string", "nullable": true }, "postcode": { "type": "string", "nullable": true }, "county": { "type": "string", "nullable": true }, "country": { "type": "string", "nullable": true } }, "description": "The residential address of the individual." }, "birth": { "type": "object", "properties": { "day": { "type": "number" }, "month": { "type": "number" }, "year": { "type": "number" } }, "required": [ "day", "month", "year" ], "description": "The birth date of the individual. If provided, all fields (day, month, year) must be specified." }, "roles": { "default": [], "type": "array", "items": { "type": "string", "enum": [ "DIRECTOR", "PSC", "SHAREHOLDER", "BENEFICIAL_OWNER", "TRUSTEE", "NOMINEE", "SECRETARY", "OTHER" ] }, "description": "The roles of this related party in the parent organisation." } }, "required": [ "object", "firstName", "lastName" ], "description": "Create a new individual and add them as a related party." }, { "type": "object", "properties": { "object": { "type": "string", "enum": [ "organisation" ] }, "name": { "type": "string", "description": "The name of the organisation." }, "type": { "type": "string", "enum": [ "COMPANY", "NON_PROFIT", "TRUST", "OTHER" ], "description": "The type of the organisation." }, "subType": { "type": "string", "description": "The sub type of the organisation." }, "identifyingNumber": { "type": "string", "description": "The identifying number of the organisation." }, "registeredAddress": { "type": "object", "properties": { "line1": { "type": "string", "nullable": true }, "line2": { "type": "string", "nullable": true }, "city": { "type": "string", "nullable": true }, "postcode": { "type": "string", "nullable": true }, "county": { "type": "string", "nullable": true }, "country": { "type": "string", "nullable": true } }, "description": "The registered address of the organisation." }, "tradingAddress": { "type": "object", "properties": { "line1": { "type": "string", "nullable": true }, "line2": { "type": "string", "nullable": true }, "city": { "type": "string", "nullable": true }, "postcode": { "type": "string", "nullable": true }, "county": { "type": "string", "nullable": true }, "country": { "type": "string", "nullable": true } }, "description": "The trading address of the organisation." }, "roles": { "default": [], "type": "array", "items": { "type": "string", "enum": [ "DIRECTOR", "PSC", "SHAREHOLDER", "BENEFICIAL_OWNER", "TRUSTEE", "NOMINEE", "SECRETARY", "OTHER" ] }, "description": "The roles of this related party in the parent organisation." } }, "required": [ "object", "name", "type" ], "description": "Create a new organisation and add it as a related party." }, { "type": "object", "properties": { "object": { "type": "string", "enum": [ "existing" ] }, "individualId": { "type": "string", "description": "The unique identifier for an existing individual to add as a related party. Either individualId or organisationId must be provided, but not both." }, "organisationId": { "type": "string", "description": "The unique identifier for an existing organisation to add as a related party. Either individualId or organisationId must be provided, but not both." }, "roles": { "default": [], "type": "array", "items": { "type": "string", "enum": [ "DIRECTOR", "PSC", "SHAREHOLDER", "BENEFICIAL_OWNER", "TRUSTEE", "NOMINEE", "SECRETARY", "OTHER" ] }, "description": "The roles of this related party in the parent organisation." } }, "required": [ "object" ], "description": "Create a related party relationship from an existing individual or organisation." } ], "description": "Create a related party. Can be from an existing individual/organisation ID, or by providing details to create a new individual or organisation." } } } }, "responses": { "201": { "description": "Related party created successfully", "content": { "application/json": { "schema": { "type": "object", "properties": { "data": { "type": "object", "properties": { "links": { "type": "object", "properties": { "self": { "type": "string", "format": "uri", "description": "The API url for this item" }, "web": { "type": "string", "format": "uri", "description": "The web url for this item" } }, "required": [ "self", "web" ] }, "id": { "type": "string", "description": "The unique identifier for the related party relationship." }, "object": { "type": "string", "enum": [ "related_party" ] }, "partyType": { "type": "string", "enum": [ "INDIVIDUAL", "ORGANISATION" ], "description": "The type of related party. Determines the type of entity that is referenced." }, "entity": { "type": "object", "properties": { "links": { "type": "object", "properties": { "self": { "type": "string", "format": "uri", "description": "The API url for this item" }, "web": { "type": "string", "format": "uri", "description": "The web url for this item" } }, "required": [ "self", "web" ] }, "id": { "type": "string", "description": "The unique identifier for the referenced entity." }, "object": { "type": "string", "enum": [ "individual", "organisation" ] } }, "required": [ "links", "id", "object" ], "description": "A reference to the entity that is the related party." }, "name": { "type": "string", "description": "The name of the related party." }, "roles": { "type": "array", "items": { "type": "string", "enum": [ "DIRECTOR", "PSC", "SHAREHOLDER", "BENEFICIAL_OWNER", "TRUSTEE", "NOMINEE", "SECRETARY", "OTHER" ] }, "description": "The roles of this related party in the parent organisation." }, "isClient": { "type": "boolean", "description": "Whether this related party is also a client." }, "createdAt": { "type": "string", "format": "date-time" } }, "required": [ "links", "id", "object", "partyType", "entity", "name", "roles", "isClient", "createdAt" ], "description": "The main response data" } }, "required": [ "data" ], "description": "Related party created successfully" } } } }, "404": { "description": "404" }, "409": { "description": "409" }, "500": { "description": "500" } } } } }, "info": { "title": "Firmcheck API", "version": "1.0.0" }, "servers": [ { "description": "Production", "url": "https://api.firmcheck.com" }, { "description": "Development", "url": "https://api.dev.beta-firmcheck.com" } ], "components": { "securitySchemes": { "bearerAuth": { "type": "http", "scheme": "bearer" } } }, "security": [ { "bearerAuth": [] } ], "x-readme": { "proxy-enabled": false } } ```