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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

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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

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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

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How It Works

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

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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

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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.

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Bridge Configuration

View the full bridge configuration: 
dokrypt bridge config

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Configuration in dokrypt.yaml

services:
  bridge:
    type: mock-bridge
    chains: [ethereum, polygon]
    confirmation_blocks: 12
    relay_delay: 30s
FieldTypeDefaultDescription
chainsstring[]requiredConnected chains
confirmation_blocksint12Blocks before relay
relay_delayduration30sDelay before relay

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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.