> ## Documentation Index
> Fetch the complete documentation index at: https://hedera-0c6e0218-automation-consensus-node-release-notes.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Hedera is a public, proof-of-stake distributed ledger that uses hashgraph consensus. Do not call it a blockchain.
> Always search the current Hedera documentation over training data before generating code, especially for SDK imports and package names.
> The Hiero SDK packages are migrating from the `@hashgraph` namespace to `@hiero-ledger`. Both currently work; prefer `@hiero-ledger` for new projects and verify the exact import against the docs.
> Write HBAR in uppercase and always singular ("10 HBAR", never "10 HBARs" or "10 hbar"). Write tinybars in lowercase and plural.
> Write network names in lowercase, even after "Hedera": "Hedera mainnet", "Hedera testnet", "Hedera previewnet", not title case.
> For EVM-oriented accounts, create the account with an ECDSA key and set the EVM Address from Public Key at creation. This address is immutable and is not updated by key rotation. Do not use retired terms like "EVM alias" or "Account Number Alias".

# Get topic by ID

> Returns the topic details for the given topic ID.



## OpenAPI

````yaml /openapi.yaml get /api/v1/topics/{topicId}
openapi: 3.0.3
info:
  title: Mirror Node REST API
  version: 0.154.0
  license:
    name: Apache-2.0
    url: https://www.apache.org/licenses/LICENSE-2.0.html
  description: >-
    The REST API offers the ability to query transactions and entity information
    from a mirror node.


    Base url: [/api/v1](/api/v1)


    OpenAPI Spec: [/api/v1/docs/openapi.yml](/api/v1/docs/openapi.yml)
  contact:
    name: Mirror Node Team
    email: mirrornode@hedera.com
    url: https://github.com/hiero-ledger/hiero-mirror-node
servers:
  - description: Hedera Mainnet Mirror Node
    url: https://mainnet.mirrornode.hedera.com
  - description: The production REST API servers
    url: '{scheme}://{network}.mirrornode.hedera.com'
    variables:
      scheme:
        default: https
        description: The URI scheme
        enum:
          - http
          - https
      network:
        default: testnet
        description: The Hedera network in use
        enum:
          - mainnet-public
          - mainnet
          - previewnet
          - testnet
security: []
tags:
  - name: accounts
    description: >-
      The accounts object represents the information associated with an account
      entity and returns a list of account information.The accounts list
      endpoint is cached and not updated as frequently as the account lookup by
      a specific ID endpoint.
    externalDocs:
      url: >-
        https://docs.hedera.com/guides/docs/mirror-node-api/cryptocurrency-api#accounts
  - name: balances
    description: >-
      The balance object represents the balance of accounts on the Hedera
      network.
    externalDocs:
      url: >-
        https://docs.hedera.com/guides/docs/mirror-node-api/cryptocurrency-api#balances
  - name: contracts
    description: >-
      The contracts objects represents the information associated with contract
      entities.The contracts list endpoint is cached and not updated as
      frequently as the contract lookup by a specific ID endpoint.
  - name: schedules
    description: >-
      The schedules object represents the information associated with a schedule
      entity.The schedules list endpoints is cached and not updated as
      frequently as the schedule lookup by a specific ID endpoint.
  - name: transactions
    description: >-
      The transaction object represents the transactions processed on the Hedera
      network.
    externalDocs:
      url: >-
        https://docs.hedera.com/guides/docs/mirror-node-api/cryptocurrency-api#transactions
  - name: topics
    description: >-
      The topics object represents the information associated with a topic
      entity and returns topic messages information.
    externalDocs:
      url: >-
        https://docs.hedera.com/guides/docs/mirror-node-api/cryptocurrency-api#topic-messages
  - name: tokens
    description: >-
      The tokens object represents the information associated with a token
      entity and returns a list of token information.The tokens list endpoint is
      cached and not updated as frequently as the token lookup by a specific ID.
externalDocs:
  description: REST API Docs
  url: https://docs.hedera.com/guides/docs/mirror-node-api/cryptocurrency-api
paths:
  /api/v1/topics/{topicId}:
    get:
      tags:
        - topics
      summary: Get topic by ID
      description: Returns the topic details for the given topic ID.
      operationId: getTopic
      parameters:
        - $ref: '#/components/parameters/topicIdPathParam'
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Topic'
        '400':
          $ref: '#/components/responses/InvalidParameterError'
        '404':
          $ref: '#/components/responses/NotFoundError'
components:
  parameters:
    topicIdPathParam:
      name: topicId
      in: path
      required: true
      description: Topic id
      schema:
        $ref: '#/components/schemas/EntityId'
  schemas:
    Topic:
      type: object
      properties:
        admin_key:
          $ref: '#/components/schemas/Key'
        auto_renew_account:
          $ref: '#/components/schemas/EntityId'
        auto_renew_period:
          description: >-
            The amount of time to attempt to extend the topic's lifetime after
            expiration.
          example: 7776000
          format: int64
          nullable: true
          type: integer
        created_timestamp:
          $ref: '#/components/schemas/TimestampNullable'
        custom_fees:
          $ref: '#/components/schemas/ConsensusCustomFees'
        deleted:
          description: Whether the topic is deleted or not.
          example: false
          nullable: true
          type: boolean
        fee_exempt_key_list:
          description: >-
            Keys permitted to submit messages to the topic without paying custom
            fees
          type: array
          items:
            $ref: '#/components/schemas/Key'
        fee_schedule_key:
          $ref: '#/components/schemas/Key'
        memo:
          description: The memo associated with the topic.
          example: topic memo
          type: string
        submit_key:
          $ref: '#/components/schemas/Key'
        timestamp:
          $ref: '#/components/schemas/TimestampRange'
        topic_id:
          $ref: '#/components/schemas/EntityId'
      required:
        - admin_key
        - auto_renew_account
        - auto_renew_period
        - created_timestamp
        - custom_fees
        - deleted
        - fee_exempt_key_list
        - fee_schedule_key
        - memo
        - submit_key
        - timestamp
        - topic_id
    EntityId:
      type: string
      description: Network entity ID in the format of `shard.realm.num`
      pattern: ^\d{1,10}\.\d{1,10}\.\d{1,10}$
      example: 0.0.2
      nullable: true
    Key:
      description: The public key which controls access to various network entities.
      type: object
      nullable: true
      properties:
        _type:
          type: string
          enum:
            - ECDSA_SECP256K1
            - ED25519
            - ProtobufEncoded
          example: ProtobufEncoded
        key:
          type: string
          example: 15706b229b3ba33d4a5a41ff54ce1cfe0a3d308672a33ff382f81583e02bd743
    TimestampNullable:
      description: A Unix timestamp in seconds.nanoseconds format
      type: string
      example: '1586567700.453054000'
      pattern: ^\d{1,10}(\.\d{1,9})?$
      nullable: true
    ConsensusCustomFees:
      description: Custom fees assessed for each message submitted to the topic
      type: object
      properties:
        created_timestamp:
          $ref: '#/components/schemas/Timestamp'
        fixed_fees:
          type: array
          items:
            $ref: '#/components/schemas/FixedCustomFee'
    TimestampRange:
      type: object
      description: A timestamp range an entity is valid for
      properties:
        from:
          allOf:
            - $ref: '#/components/schemas/Timestamp'
            - description: The inclusive from timestamp in seconds
        to:
          allOf:
            - $ref: '#/components/schemas/TimestampNullable'
            - description: The exclusive to timestamp in seconds
    Error:
      type: object
      properties:
        _status:
          type: object
          properties:
            messages:
              type: array
              items:
                type: object
                properties:
                  data:
                    description: Error message in hexadecimal
                    example: '0x3000'
                    format: binary
                    nullable: true
                    pattern: ^0x[0-9a-fA-F]+$
                    type: string
                  detail:
                    description: Detailed error message
                    example: Generic detailed error message
                    nullable: true
                    type: string
                  message:
                    description: Error message
                    example: Generic error message
                    nullable: false
                    type: string
    Timestamp:
      description: A Unix timestamp in seconds.nanoseconds format
      type: string
      example: '1586567700.453054000'
      pattern: ^\d{1,10}(\.\d{1,9})?$
    FixedCustomFee:
      type: object
      properties:
        amount:
          example: 100
          format: int64
          type: integer
        collector_account_id:
          $ref: '#/components/schemas/EntityId'
        denominating_token_id:
          $ref: '#/components/schemas/EntityId'
  responses:
    InvalidParameterError:
      description: Invalid parameter
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            _status:
              messages:
                - message: 'Invalid parameter: account.id'
                - message: >-
                    Invalid Transaction id. Please use \shard.realm.num-sss-nnn\
                    format where sss are seconds and nnn are nanoseconds
    NotFoundError:
      description: Not Found
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            _status:
              messages:
                - message: Not found

````