Cross-Chain Bridge

Overview

Dokrypt’s bridge simulator lets you test cross-chain workflows locally. It simulates token transfers between local chains by modifying balances directly — no actual cross-chain messaging protocol is involved. This is useful for:

Testing multi-chain dApps
Simulating L1↔L2 bridges
Testing cross-chain token transfers
Developing bridge aggregators

Setup

To use the bridge, your dokrypt.yaml needs multiple chains:

version: "1"
name: multi-chain-app

chains:
  ethereum:
    engine: anvil
    chain_id: 31337
    block_time: "2s"
  polygon:
    engine: anvil
    chain_id: 137
    block_time: "2s"

services:
  bridge:
    type: mock-bridge
    chains: [ethereum, polygon]

Start the environment:

dokrypt up

Sending Transfers

Simulate a cross-chain transfer:

# Bridge 100 ETH from ethereum to polygon
dokrypt bridge send ethereum polygon 100

With options:

# Specify sender
dokrypt bridge send ethereum polygon 50.5 --from 0x1234...abcd

# Bridge tokens
dokrypt bridge send polygon ethereum 1000 --token USDC

How It Works

Resolves RPC endpoints for both chains
Sends a transaction to the bridge contract (0x...B12D) on the source chain
Mines a block on the source chain
Reads the recipient’s current balance on the destination chain
Adds the bridged amount to the balance on the destination chain

Bridge Status

Check the status of bridge queues:

dokrypt bridge status

Bridge          Chains              Relay Delay   Confirmations   Queue
eth-polygon     ethereum → polygon  30s           12              0 pending

Relay Messages

Force relay pending bridge messages by mining confirmation blocks:

dokrypt bridge relay
dokrypt bridge relay --blocks 5

This mines blocks on each chain and triggers the bridge service relay endpoint.

Bridge Configuration

View the full bridge configuration:

dokrypt bridge config

Configuration in dokrypt.yaml

services:
  bridge:
    type: mock-bridge
    chains: [ethereum, polygon]
    confirmation_blocks: 12
    relay_delay: 30s

Field	Type	Default	Description
`chains`	`string[]`	required	Connected chains
`confirmation_blocks`	`int`	`12`	Blocks before relay
`relay_delay`	`duration`	`30s`	Delay before relay

Multi-Bridge Setup

You can configure multiple bridges for complex multi-chain scenarios:

chains:
  ethereum:
    engine: anvil
    chain_id: 31337
  polygon:
    engine: anvil
    chain_id: 137
  arbitrum:
    engine: anvil
    chain_id: 42161

services:
  eth-polygon-bridge:
    type: mock-bridge
    chains: [ethereum, polygon]
    confirmation_blocks: 12
  eth-arbitrum-bridge:
    type: mock-bridge
    chains: [ethereum, arbitrum]
    confirmation_blocks: 6

dokrypt bridge send ethereum polygon 100
dokrypt bridge send ethereum arbitrum 50

The bridge simulator directly modifies destination chain balances. It does not deploy or interact with actual bridge smart contracts. For testing real bridge protocol implementations, deploy the bridge contracts as part of your project.

Getting Started

Core Concepts

Features

Advanced

Cross-Chain Bridge

Overview

Setup

Sending Transfers

How It Works

Bridge Status

Relay Messages

Bridge Configuration

Configuration in dokrypt.yaml

Multi-Bridge Setup

​Overview

​Setup

​Sending Transfers

​How It Works

​Bridge Status

​Relay Messages

​Bridge Configuration

​Configuration in dokrypt.yaml

​Multi-Bridge Setup

Overview

Setup

Sending Transfers

How It Works

Bridge Status

Relay Messages

Bridge Configuration

Configuration in dokrypt.yaml

Multi-Bridge Setup