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Transactions — HCS‑7

These helpers produce signed-ready Hedera TopicMessageSubmitTransaction objects. They are useful when you need to integrate HCS‑7 messages into other toolchains (agent schedulers, custom wallets, etc.) without instantiating HCS7Client.

Sources:

Import:

import {
  buildHcs7CreateRegistryTx,
  buildHcs7SubmitMessageTx,
  buildHcs7EvmMessageTx,
  buildHcs7WasmMessageTx,
} from '@hashgraphonline/standards-sdk/hcs-7/tx';

buildHcs7CreateRegistryTx​

const tx = buildHcs7CreateRegistryTx({
  ttl: 86_400,
  submitKey: operatorPublicKey,
  adminKey: operatorPublicKey,
  operatorPublicKey,
});
  • Memo is auto-set to hcs-7:indexed:{ttl}.
  • Pass submitKey: true / adminKey: true to reuse the operator key.
  • Returns a TopicCreateTransaction you can sign with the Hedera SDK.

buildHcs7SubmitMessageTx​

const tx = buildHcs7SubmitMessageTx({
  topicId: '0.0.10058300',
  message: {
    op: 'register-config',
    t: 'evm',
    c: { /* ... */ },
  },
  transactionMemo: 'hcs7-config',
});

Wraps an arbitrary HCS‑7 payload with p: 'hcs-7' before serializing and attaching it to the topic message.

buildHcs7EvmMessageTx​

const tx = buildHcs7EvmMessageTx({
  topicId: '0.0.10058300',
  config: {
    contractAddress: '0x1d67aaf7f7e8d806bbeba24c4dea24808e1158b8',
    abi: {
      name: 'minted',
      inputs: [],
      outputs: [{ name: '', type: 'uint64' }],
      stateMutability: 'view',
      type: 'function',
    },
    m: 'LaunchPage minted',
  },
  transactionMemo: 'hcs7-evm',
});

Produces the canonical register-config payload for EVM readers:

{
  "p": "hcs-7",
  "op": "register-config",
  "t": "evm",
  "c": { "contractAddress": "…", "abi": { … } },
  "m": "LaunchPage minted"
}

buildHcs7WasmMessageTx​

const tx = buildHcs7WasmMessageTx({
  topicId: '0.0.10058300',
  config: {
    wasmTopicId: '0.0.5269810',
    inputType: {
      stateData: {
        minted: 'number',
        tokensRemaining: 'number',
      },
    },
    outputType: {
      type: 'string',
      format: 'topic-id',
    },
    m: 'mint router',
  },
  transactionMemo: 'hcs7-wasm',
});

Emits the register-config payload required for WASM routers.

Signing + Sending​

Each builder returns a Hedera SDK transaction object. Use the standard pattern to sign and submit:

const client = Client.forTestnet().setOperator(operatorId, operatorKey);
await tx.freezeWith(client);
await tx.sign(operatorKey);
const receipt = await tx.execute(client).then(res => res.getReceipt(client));

For multi-sig workflows, sign with multiple keys before calling .execute().