# Overview

KAT Bridge is a cross-chain bridging platform developed by the **Kaspa Alliance for Transparency** in collaboration with **Zealous Swap**. It connects Kaspa Layer 1 to multiple EVM-compatible networks, allowing assets to move between chains while preserving the security guarantees of both.

The platform currently operates three distinct bridge types, each designed for a specific asset class and transfer pattern.

***

## Bridge Types

### Token Bridge — KRC-20 ↔ ERC-20

The flagship bridge. Bidirectional transfers between KRC-20 inscriptions on Kaspa L1 and ERC-20 smart contracts on supported EVM networks. Uses a commit-reveal deposit scheme on L1 and a burn/mint model on L2, secured by five independent relayers. Deposits require 5/5 attestations; withdrawals use FROST threshold signatures (3-of-5).

Supported destination networks: **Kasplex** and **Igra**.

→ [Token Bridge Guide](https://kaspakat.gitbook.io/kat-bridge/guides/token-bridge-guide)

### KAS Bridge — KAS ↔ iKAS

A bidirectional bridge between native KAS on Kaspa L1 and iKAS (the native gas token on Igra). Entry deposits send KAS to the bridge vault with a KAT payload encoding the destination EVM address. Exits lock iKAS in the KasBridge smart contract, and relayers release KAS to the user's Kaspa address via FROST threshold signing.

→ [KAS Bridge Guide](https://kaspakat.gitbook.io/kat-bridge/guides/kas-bridge-guide)

### NFT Bridge — KRC-721 ↔ ERC-721

Bridges individual NFTs between Kaspa and EVM networks. Uses a governance contract with multi-signature minter consensus — multiple independent minters must vote to confirm each NFT transfer before it is minted on the destination chain. Supports royalty preservation via ERC-2981.

Supported destination networks: **Kasplex**, **Igra**, and **Ethereum**.

→ [NFT Bridge Guide](https://kaspakat.gitbook.io/kat-bridge/guides/nft-bridge-guide)

***

## Security at a Glance

All three bridges share foundational security principles:

* **No single point of failure.** The token bridge requires 3-of-5 FROST threshold signatures from independent relayers. The NFT bridge requires multi-minter consensus. Neither can be compromised by a single operator.
* **Finality before action.** Bridge logic waits for confirmed blocks on both chains before processing any transfer.
* **On-chain verifiability.** Contract addresses, relayer commitments, and audit reports are published publicly.
* **Transparency.** The K.A.T. Foundation maintains public documentation, security audits, and operational disclosures.

→ [Security Model](https://kaspakat.gitbook.io/kat-bridge/technical-architecture/security-model-frost-and-invariants) · [Security Audit](https://github.com/Nacho-the-Kat/kat-bridge-audit)

***

## Supported Networks

| Network  | Type      | Chain ID | Bridge Types    |
| -------- | --------- | -------- | --------------- |
| Kaspa    | L1 (UTXO) | —        | Token, KAS, NFT |
| Kasplex  | L2        | 202555   | Token, NFT      |
| Igra     | L2        | 38833    | Token, KAS, NFT |
| Ethereum | L1        | 1        | NFT             |

→ [Full network details](https://kaspakat.gitbook.io/kat-bridge/networks-and-tokens/supported-networks)

***

## Quick Links

* **Bridge UI:** [katbridge.com](https://katbridge.com)
* **NFT Bridge UI:** [nft.katbridge.com](https://nft.katbridge.com)
* **Source Code:** [github.com/Nacho-the-Kat](https://github.com/Nacho-the-Kat)
* **Security Audit:** [kat-bridge-audit](https://github.com/Nacho-the-Kat/kat-bridge-audit)
* **Support:** [Discord](https://discord.gg/TGA76ahDeb)