# allset-sdk

**GitHub:** [fastxyz/fast-sdk](https://github.com/fastxyz/fast-sdk/blob/main/packages/allset-sdk/README.md)

## What You Can Do

AllSet is the bridge SDK for moving tokens between the Fast payment network and EVM-compatible chains. Use it when you need to:

* **Deposit tokens into Fast** — move tokens from an EVM chain (Ethereum, Arbitrum, Base, etc.) onto the Fast network for fast, low-cost payments
* **Withdraw tokens from Fast** — move tokens from Fast back to an EVM chain to access DeFi, CEXs, or external services
* **Execute custom intents** — define arbitrary EVM operations (swap, supply, any contract call) that get executed on your behalf on the destination chain after funds settle on Fast

AllSet is designed to be **pure** — no embedded chain configs, no environment variables, no file system access. You pass all addresses, RPC URLs, and credentials explicitly, making it easy to test and predictable in any environment.

## Installation

Install from npm as `@fastxyz/allset-sdk`. The package README on GitHub includes the current install command, dependency expectations, and integration examples.

## Architecture

AllSet bridges two ecosystems: EVM chains and the Fast payment network. The key abstraction is the **intent** — a declaration of what you want to happen on the destination chain, paired with funds on Fast to pay for it.

| Function              | Role                                                                                                                              |
| --------------------- | --------------------------------------------------------------------------------------------------------------------------------- |
| `createEvmWallet()`   | Creates an EVM wallet from a private key, or generates a fresh random wallet for one-time bridging operations                     |
| `createEvmExecutor()` | Creates a viem `PublicClient` + `WalletClient` bound to a specific EVM chain                                                      |
| `executeDeposit()`    | Locks tokens on the EVM chain and issues a corresponding balance on Fast                                                          |
| `executeWithdraw()`   | Releases or debits tokens on Fast and unlocks them on the destination EVM chain                                                   |
| `executeIntent()`     | Combines a Fast-side token transfer with a predefined EVM execution plan; the intent is processed by the AllSet payment processor |

## Supported Chains

| Chain            | Chain ID | Role in AllSet                  |
| ---------------- | -------- | ------------------------------- |
| Ethereum Mainnet | 1        | Primary production EVM endpoint |
| Sepolia          | 11155111 | Testnet for EVM side            |
| Arbitrum         | 42161    | L2 deposit target               |
| Arbitrum Sepolia | 421614   | Testnet for L2 side             |
| Base             | 8453     | L2 deposit target               |

## How Deposits Work (EVM → Fast)

Depositing moves value from an EVM chain onto Fast. The tokens are locked in a lock contract on the EVM side, and an equivalent amount is issued or credited on Fast.

```
User EVM wallet
    │
    │  executeDeposit()
    │  ── tokens sent to lock contract on EVM
    ▼
EVM Lock Contract (holds tokens)
    │
    │  Payment processor detects event on EVM, submits to Fast
    ▼
Fast Network (credits user's Fast account)
    │
    │  Now usable for Fast-native fast/cheap payments
    ▼
User Fast account (via fast-sdk)
```

**Key properties:**

* Deposits require EVM gas — budget for that in your UX
* Finality on Fast is fast (seconds), but EVM event observation takes 1-3 minutes depending on chain
* Track deposit progress using the response returned by the SDK together with your application or relayer-side status handling

## How Withdrawals Work (Fast → EVM)

Withdrawing moves value from Fast back to an EVM chain. Tokens are released or debited on Fast, and the AllSet payment processor submits a transaction on the EVM destination chain to release the tokens to your wallet.

```
User Fast account
    │
    │  executeWithdraw()
    │  ── tokens debited on Fast
    ▼
AllSet Payment Processor (detects Fast event)
    │
    │  Submits release transaction on EVM destination chain
    ▼
EVM destination wallet (tokens arrive)
```

**Key properties:**

* Withdrawals are asynchronous — the Fast side settles quickly, but EVM delivery depends on payment processor queuing and EVM gas
* The payment processor takes a small fee in FAST for the forwarding service
* Use the returned order identifier to track payment status in your integration

## How Custom Intents Work

Intents unlock powerful composeability. Instead of just bridging tokens, you can specify what should happen on the destination EVM chain — a swap, a lending deposit, a specific contract call — and AllSet executes it automatically after your Fast funds are credited.

```
User Fast account
    │
    │  executeIntent()
    │  ── funds debited on Fast, intent registered
    ▼
Fast Network (credits funds, intent detected)
    │
    │  Payment processor detects intent on Fast
    ▼
Payment Processor (executes EVM operation)
    │
    │  Submits intent execution on EVM destination chain
    ▼
EVM destination (swap, deposit, contract call — result)
```

The payment processor detects the intent on Fast, credits the funds, and executes the described operation on the EVM destination chain — all as one atomic cross-chain workflow from the user's perspective. For intent examples with complete code, see the [AllSet SDK README on GitHub](https://github.com/fastxyz/fast-sdk/blob/main/packages/allset-sdk/README.md).

## Design Principles

All functions are **pure** — the SDK never reads from `process.env`, never reads a config file, and never embeds chain IDs or contract addresses. This means:

* You control exactly which chain and contract addresses your app uses
* Tests can swap in mock executors without SDK changes
* No surprises when new chains are added — you opt in explicitly

***

**For complete API documentation, runnable examples for deposits, withdrawals, and intents, and current configuration details, see the** [**AllSet SDK README on GitHub**](https://github.com/fastxyz/fast-sdk/blob/main/packages/allset-sdk/README.md)**.**


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