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Overview — HCS‑15 Petal Accounts

HCS‑15 introduces Petal accounts: lightweight sub‑accounts that share the same private key as a user’s base account. Petals let you isolate identity, balances, and app state per experience while keeping a single signing key.

What HCS‑15 Enables​

  • Multiple on‑chain personas under one key (e.g., per‑app profiles)
  • Isolated balances and escrows per Petal
  • Consistent signing and authorization via a single private key

Who Is This For?​

  • Apps that want separate “personas” (gaming, finance, social) under one wallet
  • Teams that need clean accounting per experience without multiple seed phrases
  • Users who want isolation without additional key management

Architecture​

  • Base client exposes verification and shared utilities.
  • Environment‑specific clients handle signing and submission:
    • HCS15Client (Node) uses operator credentials
    • HCS15BrowserClient (Browser) uses a connected wallet (DAppSigner)
  • All transactions are assembled by tx.ts builders (no JSON assembly in clients).

When To Use (and Not Use)​

  • Use when you need separate account ids for isolation or quotas under one owner
  • Don’t use if each persona needs a different signing key (use fully separate accounts instead)

Costs and Limits​

  • Creating accounts costs HBAR (initial balance + fees)
  • Petals reuse the base key, so no extra key custody required

Quickstart (Copy/Paste)​

import { HCS15Client } from '@hashgraphonline/standards-sdk';
const c = new HCS15Client({ network: 'testnet', operatorId, operatorKey });
const base = await c.createBaseAccount({ initialBalance: 10 });
await c.createPetalAccount({ basePrivateKey: base.privateKey });

FAQ​

  • Is a Petal truly independent? It has its own account id and balance but shares the same signing key.
  • Can I revoke a Petal? Move funds out and stop using it; key custody is shared, so revocation is social/operational.

Where to Next​

  1. Node SDK: /docs/libraries/standards-sdk/hcs-15/server
  2. Browser SDK: /docs/libraries/standards-sdk/hcs-15/browser
  3. Transactions: /docs/libraries/standards-sdk/hcs-15/tx
  4. API Reference: /docs/libraries/standards-sdk/hcs-15/api