> ## Documentation Index
> Fetch the complete documentation index at: https://base-a060aa97-docs-add-b20-spec.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# B20 token standard

> Build with Base-native B20 tokens: ERC-20 compatible precompile tokens with roles, policy scopes, memos, supply caps, pausing, and variants.

B20 is Base's native token standard: an ERC-20 superset implemented as Rust precompiles. Standard ERC-20 calls such as `transfer`, `transferFrom`, `approve`, `balanceOf`, and `allowance` work unchanged, so existing wallets, indexers, and app integrations can treat a B20 token like an ERC-20 token.

B20 adds issuer-grade controls at the chain level: policy-gated transfers and mints, role-based administration, granular pausing, supply caps, memos, ERC-2612 `permit`, and variant-specific features for assets and stablecoins.

## Choose your path

<CardGroup cols={3}>
  <Card title="Launch a token" icon="rocket" href="/get-started/launch-b20-token">
    Create a B20 token with the factory and mint the first supply.
  </Card>

  <Card title="Understand policies" icon="shield-check" href="/base-chain/specs/upgrades/beryl/b20/specification/concepts/policies-and-scopes">
    Learn how token policy scopes point to PolicyRegistry entries.
  </Card>

  <Card title="Find constants" icon="table" href="/base-chain/specs/upgrades/beryl/b20/specification/reference/constants-and-addresses">
    Copy precompile addresses, role IDs, policy scopes, variant bytes, and sentinels.
  </Card>
</CardGroup>

## Variants

| Variant    |                     Decimals | Address byte | Use when                                                                                          |
| ---------- | ---------------------------: | -----------: | ------------------------------------------------------------------------------------------------- |
| Asset      | 6-18, configured at creation |       `0x00` | You need asset features such as scaled balances, announcements, batch minting, or extra metadata. |
| Stablecoin |                    Fixed `6` |       `0x01` | You need a fixed-decimal token with a self-declared currency code.                                |

## Learn the model

* [Architecture & precompiles](/base-chain/specs/upgrades/beryl/b20/specification/concepts/architecture-and-precompiles): why B20 is configured through fixed precompile surfaces instead of deployed bytecode.
* [Policies & scopes](/base-chain/specs/upgrades/beryl/b20/specification/concepts/policies-and-scopes): how token scopes point to registry policies and gate operations.
* [Roles & access control](/base-chain/specs/upgrades/beryl/b20/specification/concepts/roles-and-access-control): who can mint, pause, seize, change metadata, and renounce administration.
* [Token lifecycle](/base-chain/specs/upgrades/beryl/b20/specification/concepts/token-lifecycle): how creation, initCalls, operation, and admin renunciation fit together.
* [Variants: Asset vs Stablecoin](/base-chain/specs/upgrades/beryl/b20/specification/concepts/variants-asset-vs-stablecoin): how to choose a token variant.