> ## Documentation Index > Fetch the complete documentation index at: https://docs.lerian.studio/llms.txt > Use this file to discover all available pages before exploring further. # Create a Metadata Index > Use this endpoint to create a metadata index for a specific entity type. Metadata indexes improve query performance when filtering or searching by custom metadata fields. ## OpenAPI ````yaml /en/openapi/v3-current/ledger.yaml post /v1/settings/metadata-indexes/entities/{entity_name} openapi: 3.1.0 info: title: Midaz Ledger API description: >- Complete API reference for Midaz Ledger services including organization management, ledger operations, assets, segments, portfolios, accounts, account types, transactions, operations, balances, operation routes, transaction routes, and metadata indexes. version: 3.7.1 servers: - url: https://ledger.sandbox.lerian.net security: [] tags: - name: Organizations API - name: Ledgers API - name: Assets API - name: Segments API - name: Portfolios API - name: Account Types API - name: Accounts API - name: Balances API - name: Transactions API - name: Operations API - name: Operation Routes API - name: Transaction Routes API - name: Metadata Indexes API paths: /v1/settings/metadata-indexes/entities/{entity_name}: post: tags: - Metadata Indexes API summary: Create a Metadata Index description: >- Use this endpoint to create a metadata index for a specific entity type. Metadata indexes improve query performance when filtering or searching by custom metadata fields. parameters: - $ref: '#/components/parameters/EntityName' - $ref: '#/components/parameters/Authorization' - $ref: '#/components/parameters/ContentType' - $ref: '#/components/parameters/XRequestId' requestBody: content: application/json: schema: $ref: '#/components/schemas/CreateMetadataIndexRequest' example: metadataKey: tier unique: false sparse: true required: true responses: '201': description: >- Indicates that the metadata index was successfully created and the operation was completed as expected. content: application/json: schema: $ref: '#/components/schemas/MetadataIndexResponse' example: indexName: metadata.tier_1 entityName: transaction metadataKey: tier unique: false sparse: true headers: {} '400': description: '' content: application/json: schema: $ref: '#/components/schemas/ErrorFormat' examples: Error0009: $ref: '#/components/examples/Error0009' Error0047: $ref: '#/components/examples/Error0047' Error0132: $ref: '#/components/examples/Error0132' Error0134: $ref: '#/components/examples/Error0134' Error0135: $ref: '#/components/examples/Error0135' Error0136: $ref: '#/components/examples/Error0136' Error0138: $ref: '#/components/examples/Error0138' headers: {} '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/ErrorFormat' examples: Error0041: $ref: '#/components/examples/Error0041' Error0042: $ref: '#/components/examples/Error0042' '403': description: Forbidden content: application/json: schema: $ref: '#/components/schemas/ErrorFormat' examples: Error0043: $ref: '#/components/examples/Error0043' '500': description: Internal Server Error content: application/json: schema: $ref: '#/components/schemas/ErrorFormat' examples: Error0046: $ref: '#/components/examples/Error0046' security: - bearer: [] components: parameters: EntityName: name: entity_name in: path description: >- The name of the entity for which the metadata index will be created or managed. required: true example: transaction schema: type: string enum: - organization - ledger - asset - segment - portfolio - account - transaction - operation - account_type - operation_route - transaction_route Authorization: name: Authorization in: header description: >- The authorization token. **This header is required if your environment has Access Manager enabled**. required: false schema: type: string ContentType: name: Content-Type in: header description: >- The type of media of the resource. Recommended value is `application/json`. required: false example: application/json schema: type: string XRequestId: name: X-Request-Id in: header description: A unique identifier used to trace and track each request. required: false example: 019c96a0-0a98-7287-9a31-786e0809c769 schema: type: string format: uuid schemas: CreateMetadataIndexRequest: type: object description: The request body to create a metadata index. required: - metadataKey properties: metadataKey: type: string maxLength: 100 description: >- The metadata key to be indexed. This key must match the metadata field name used in your entities. examples: - tier unique: type: boolean default: false description: >- Indicates whether the index enforces uniqueness. When set to `true`, duplicate values for this metadata key will not be allowed. examples: - false sparse: type: boolean default: true description: >- Indicates whether the index is sparse. When set to `true`, only documents containing the indexed field will be included in the index. examples: - true MetadataIndexResponse: type: object description: The response body for a metadata index. required: - indexName - entityName - metadataKey - unique - sparse properties: indexName: type: string description: The name of the index in the database. examples: - metadata.tier_1 entityName: type: string description: The name of the entity associated with the index. examples: - transaction metadataKey: type: string description: The metadata key used in the index. examples: - tier unique: type: boolean description: Indicates whether the index enforces uniqueness. examples: - false sparse: type: boolean description: >- Indicates whether the index is sparse (ignores documents without the indexed field). examples: - true ErrorFormat: type: object description: The response message error. required: - code - title - message properties: code: type: string description: A unique, stable identifier for the error. title: type: string description: A brief summary of the issue. message: type: string description: Detailed guidance for resolving the error. fields: type: object additionalProperties: true description: Additional information about the fields that caused the error. examples: Error0009: summary: Missing Fields in Request value: code: '0009' title: Missing Fields in Request message: >- Your request is missing one or more required fields. Please refer to the documentation to ensure all necessary fields are included in your request. fields: metadataKey: metadataKey is a required field Error0047: summary: Bad Request value: code: '0047' title: Bad Request message: >- The server could not understand the request due to malformed syntax. Please check the listed fields and try again. Error0132: summary: Metadata Index Already Exists value: code: '0132' title: Metadata Index Already Exists message: >- A metadata index with the same key already exists for this entity. Please use a different key from the existing index. Error0134: summary: Invalid Metadata Key Format value: code: '0134' title: Invalid Metadata Key Format message: >- The metadata key format is invalid. Keys must start with a letter and contain only alphanumeric characters and underscores. Error0135: summary: Metadata Index Limit Exceeded value: code: '0135' title: Metadata Index Limit Exceeded message: >- The maximum number of metadata indexes has been reached for this entity. Please delete unused indexes before creating new ones. Error0136: summary: Metadata Index Creation Failed value: code: '0136' title: Metadata Index Creation Failed message: >- The metadata index could not be created. Please try again later or contact support. Error0138: summary: Invalid Entity Name value: code: '0138' title: Invalid Entity Name message: >- The provided entity name is not valid. Accepted values are: organization, ledger, asset, segment, portfolio, account, transaction, operation, account_type, operation_route, transaction_route. Error0041: summary: Token Missing value: code: '0041' title: Token Missing message: >- A valid token must be provided in the request header. Please include a token and try again. Error0042: summary: Invalid Token value: code: '0042' title: Invalid Token message: >- The provided token is expired, invalid or malformed. Please provide a valid token and try again. Error0043: summary: Insufficient Privileges value: code: '0043' title: Insufficient Privileges message: >- You do not have the necessary permissions to perform this action. Please contact your administrator if you believe this is an error. Error0046: summary: Internal Server Error value: code: '0046' title: Internal Server Error message: >- The server encountered an unexpected error. Please try again later or contact support. securitySchemes: bearer: type: http scheme: bearer ````