Topics

Overview

The Topics endpoints in the Hedera Mirror Node REST API allows developers to query topics and messages. These endpoints are crucial for retrieving topic details, message history, and tracking consensus events on the network.

Endpoints

The following endpoints are available for the Topics object:

Endpoint	Description
GET /api/v1/topics/{id}/messages	Retrieves messages for a specific topic by ID.
GET /api/v1/topics/{id}/messages/{sequence_number}	Fetches a specific message from a topic using sequence number.
GET /api/v1/topics/{id}/messages/{consensusTimestamp}	Retrieves a topic message by consensus timestamp.
GET /api/v1/topics/{topicid}	Retrieves the topic details for the given topic ID.

Topics

List topic messages by id

get

Returns the list of topic messages for the given topic id.

Path parameters

topicIdstring | nullablerequired

Network entity ID in the format of shard.realm.num

Example: 0.0.2

Pattern: ^\d{1,10}\.\d{1,10}\.\d{1,10}$

Query parameters

encodingstringoptional

Example: base64

limitinteger · int32 · min: 1 · max: 100 · default: 25optional

The maximum number of items to return

Example: 2

orderundefined · enum · default: "asc"optional

The order in which items are listed

Example: desc

Options: asc, desc

sequencenumberinteger · int64optional

Example: 2

timestampstring[]optional

The consensus timestamp as a Unix timestamp in seconds.nanoseconds format with an optional comparison operator. See unixtimestamp.com for a simple way to convert a date to the 'seconds' part of the Unix time.

Example: {"summary":"--","value":""}

Responses

application/json

application/json

application/json

cURL

JavaScript

Python

HTTP

cURL

curl -L \
  --url '/api/v1/topics/{topicId}/messages'

200

400

404

200

{
  "messages": [
    {
      "chunk_info": {
        "initial_transaction_id": "0.0.10-1234567890-000000321",
        "nonce": 3,
        "number": 1,
        "total": 2,
        "scheduled": true
      },
      "consensus_timestamp": "1234567890.000000001",
      "message": "bWVzc2FnZQ==",
      "payer_account_id": "0.0.10",
      "running_hash": "cnVubmluZ19oYXNo",
      "running_hash_version": 2,
      "sequence_number": 1,
      "topic_id": "0.0.7"
    }
  ],
  "links": {
    "next": null
  }
}

OK

Response Details

Response Item	Description
consensus_timestamp	The consensus timestamp of the message in seconds.nanoseconds
topic_id	The ID of the topic the message was submitted to
payer_account_id	The account ID that paid for the transaction to submit the message
message	The content of the message
running_hash	The new running hash of the topic that received the message
sequence_number	The sequence number of the message relative to all other messages for the same topic

Get topic message by id and sequence number

get

Returns a single topic message for the given topic id and sequence number.

Path parameters

topicIdstring | nullablerequired

Network entity ID in the format of shard.realm.num

Example: 0.0.2

Pattern: ^\d{1,10}\.\d{1,10}\.\d{1,10}$

sequenceNumberinteger · int64required

Topic message sequence number

Example: 2

Responses

application/json

application/json

application/json

cURL

JavaScript

Python

HTTP

cURL

curl -L \
  --url '/api/v1/topics/{topicId}/messages/{sequenceNumber}'

200

400

404

200

{
  "chunk_info": {
    "initial_transaction_id": "0.0.10-1234567890-000000321",
    "nonce": 3,
    "number": 1,
    "total": 2,
    "scheduled": true
  },
  "consensus_timestamp": "1234567890.000000001",
  "message": "bWVzc2FnZQ==",
  "payer_account_id": "0.0.10",
  "running_hash": "cnVubmluZ19oYXNo",
  "running_hash_version": 2,
  "sequence_number": 1,
  "topic_id": "0.0.7"
}

OK

Get topic message by consensusTimestamp

get

Returns a topic message the given the consensusTimestamp.

Path parameters

timestampstringrequired

The Unix timestamp in seconds.nanoseconds format, the timestamp at which the associated transaction reached consensus. See unixtimestamp.com for a simple way to convert a date to the 'seconds' part of the Unix time.

Example: 1234567890.0000007

Pattern: ^\d{1,10}(.\d{1,9})?$

Responses

application/json

application/json

application/json

cURL

JavaScript

Python

HTTP

cURL

curl -L \
  --url '/api/v1/topics/messages/{timestamp}'

200

400

404

200

{
  "chunk_info": {
    "initial_transaction_id": "0.0.10-1234567890-000000321",
    "nonce": 3,
    "number": 1,
    "total": 2,
    "scheduled": true
  },
  "consensus_timestamp": "1234567890.000000001",
  "message": "bWVzc2FnZQ==",
  "payer_account_id": "0.0.10",
  "running_hash": "cnVubmluZ19oYXNo",
  "running_hash_version": 2,
  "sequence_number": 1,
  "topic_id": "0.0.7"
}

OK