> ## 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.

# IB20Factory.createB20

> Generated B20 reference for createB20(B20Variant,bytes32,bytes,bytes[]).

[Related concept](/base-chain/specs/upgrades/beryl/b20/specification/implementation/deployment-and-initcalls-encoding)

## Signature

```solidity theme={null}
function createB20(B20Variant variant, bytes32 salt, bytes calldata params, bytes[] calldata initCalls) external payable returns (address token);
```

| Field               | Value                                         |
| ------------------- | --------------------------------------------- |
| Selector            | `0xb263cb84`                                  |
| Canonical signature | `createB20(B20Variant,bytes32,bytes,bytes[])` |

## Description

Creates a B-20 token of the given `variant` at the deterministic address derived
from `(variant, msg.sender, salt)`, then dispatches each entry in `initCalls` on
the new token. Emits `B20Created`.
Dev: Reverts with `NonPayable` when ETH is attached to the call.
Dev: Reverts with IActivationRegistry.FeatureNotActivated when the variant feature is not activated.
Dev: Reverts with `InvalidVariant` when `variant` is outside the `B20Variant` range.
Dev: Reverts with `UnsupportedVersion` when the leading `version` byte in `params` is unrecognized for `variant`.
Dev: Reverts with `MissingRequiredField` when a required string field is empty (e.g. stablecoin `currency`).
Dev: Reverts with `InvalidCurrency` when a stablecoin `currency` is non-empty but contains a non-`A`-`Z` byte.
Dev: Reverts with `InvalidDecimals` when an asset `decimals` is outside `[B20Constants.MIN_ASSET_DECIMALS, B20Constants.MAX_ASSET_DECIMALS]`.
Dev: Reverts with `TokenAlreadyExists` when a token already exists at the derived address.
Dev: Reverts with `InitCallFailed` (or the bubbled inner reason) when any entry in `initCalls` reverts.
Dev: Each `initCall` executes on the new token within the creation (bootstrap) window, during which
factory-originated calls bypass the token's role gates and its transfer-side policy gates
(`TRANSFER_SENDER_POLICY`, `TRANSFER_RECEIVER_POLICY`, `TRANSFER_EXECUTOR_POLICY`) — so admin-gated
setup (e.g. `grantRole`, `updatePolicy`, `updateSupplyCap`) and bootstrap transfers succeed without
the factory holding any role. The bypass is deliberately NOT total:

* `MINT_RECEIVER_POLICY` is ALWAYS enforced, including for factory-originated mints, so new supply is
  never issued to a policy-denied recipient even at creation. An `initCalls` bundle that sets a
  restrictive `MINT_RECEIVER_POLICY` and then mints to a non-authorized account reverts
  `PolicyForbids(MINT_RECEIVER_POLICY, ...)` (bubbled out of `createB20`).
* Pause is never bypassed. It defaults to nothing-paused at creation, so a start-paused
  configuration must sequence its `pause(...)` call last among the `initCalls`.
* Token invariants (supply-cap math, balance accounting) are never bypassed.
  The window closes when `createB20` returns; the factory retains no persisted access.
  Param: variant   Which variant struct `params` decodes as.
  Param: salt      Caller-chosen salt for deterministic address derivation.
  Param: params    ABI-encoded variant-specific creation struct, leading with the version byte.
  Param: initCalls Bootstrap calls invoked on the new token after identity is sealed.
  Return: token The address of the newly created token.

## Access control

Read-only or ERC-20-standard access rules unless the NatSpec states otherwise.

## Policy interaction

No direct policy interaction.

## Example

```solidity theme={null}
address token = StdPrecompiles.B20_FACTORY.createB20(variant, salt, params, initCalls);
```

## Related

* [IB20Factory reference](/base-chain/specs/upgrades/beryl/b20/specification/reference/interfaces/IB20Factory)
* [Constants & addresses](/base-chain/specs/upgrades/beryl/b20/specification/reference/constants-and-addresses)