ZigZag Arweave Bridge Skill

The Arweave Bridge is a service built by ZigZag Exchange that enables zkSync transactions to access permanent storage on Arweave. It provides a seamless way for Layer 2 users to store data permanently without needing to acquire AR tokens directly.

Core Value Proposition: Access Arweave permanent storage at $1/MB by paying directly on zkSync with stablecoins.

When to Use This Skill

This skill should be triggered when:

• Building dApps that need permanent, decentralized file storage
• Storing NFT metadata permanently from Layer 2 networks
• Creating permissionless listing systems that need public metadata storage
• Integrating Arweave storage into zkSync applications
• Needing a bridge between L2 payments and permanent storage
• Implementing file upload systems with cryptographic authentication
• Building applications that require immutable data storage guarantees

Quick Reference

Base URL

https://zigzag-arweave-bridge.herokuapp.com/

Payment Address (zkSync)

0xcb7aca0cdea76c5bd5946714083c559e34627607

Supported Tokens

• USDC
• USDT
• DAI

Conversion Rate

1 MB per $1 of stablecoin deposited

API Endpoints

1. Check Allocation

Query remaining storage bytes for an address.

Endpoint:

GET /allocation/zksync?address={wallet_address}

Response:

{
  "remaining_bytes": 1048576
}

Example:

curl "https://zigzag-arweave-bridge.herokuapp.com/allocation/zksync?address=0xYourWalletAddress"

2. Get Server Time

Get current server timestamp for signature generation.

Endpoint:

GET /time

Response:

{
  "timestamp": 1640000000000
}

Example:

curl "https://zigzag-arweave-bridge.herokuapp.com/time"

3. Upload File

Upload a file to Arweave permanent storage.

Endpoint:

POST /arweave/upload

Content-Type:

multipart/form-data

Required Fields:

sender

file

timestamp

signature

{sender}:{timestamp}

Response:

{
  "arweave_tx_id": "abc123...",
  "remaining_bytes": 1000000
}

Authentication

All uploads require cryptographic signature verification:

1. Get current server timestamp from

   /time

2. Create message:

   {sender_address}:{timestamp}

3. Sign message with your Ethereum private key (ECDSA)
4. Include signature in upload request

Message Format:

0xYourAddress:1640000000000

Complete Upload Example (Node.js)

import { FormData, fileFromPath } from "formdata-node";
import fetch from "node-fetch";
import { ethers } from "ethers";
import dotenv from "dotenv";

dotenv.config();

const BASE_URL = "https://zigzag-arweave-bridge.herokuapp.com";

async function uploadToArweave(filePath) {
  // 1. Get current server time
  const timeResponse = await fetch(`${BASE_URL}/time`);
  const { timestamp } = await timeResponse.json();

  // 2. Create wallet and sign message
  const wallet = new ethers.Wallet(process.env.ETH_PRIVKEY);
  const sender = wallet.address;
  const message = `${sender}:${timestamp}`;
  const signature = await wallet.signMessage(message);

  // 3. Prepare form data
  const formData = new FormData();
  formData.append("sender", sender);
  formData.append("timestamp", timestamp.toString());
  formData.append("signature", signature);
  formData.append("file", await fileFromPath(filePath));

  // 4. Upload file
  const response = await fetch(`${BASE_URL}/arweave/upload`, {
    method: "POST",
    body: formData,
  });

  const result = await response.json();
  console.log("Arweave TX ID:", result.arweave_tx_id);
  console.log("Remaining bytes:", result.remaining_bytes);

  return result;
}

// Usage
uploadToArweave("./my-file.json");

Dependencies

{
  "dependencies": {
    "formdata-node": "^4.0.0",
    "node-fetch": "^3.0.0",
    "ethers": "^5.0.0",
    "dotenv": "^10.0.0"
  }
}

Environment Variables

# Required for signing uploads
ETH_PRIVKEY=your_private_key_here

Workflow

Step 1: Fund Your Allocation

Send stablecoins on zkSync to the bridge address:

Address: 0xcb7aca0cdea76c5bd5946714083c559e34627607
Network: zkSync
Tokens: USDC, USDT, or DAI
Rate: $1 = 1 MB storage

Credits typically appear within 1-2 minutes.

Step 2: Check Your Allocation

const response = await fetch(
  `${BASE_URL}/allocation/zksync?address=${yourAddress}`
);
const { remaining_bytes } = await response.json();
console.log(`Available storage: ${remaining_bytes / 1024 / 1024} MB`);

Step 3: Upload Files

Use the complete upload example above, ensuring:

• Timestamp is current (stale timestamps are rejected)
• Signature is valid for your address
• File size doesn't exceed your allocation

Step 4: Access Your Data

Once uploaded, your file is permanently stored on Arweave:

https://arweave.net/{arweave_tx_id}

Use Cases

NFT Metadata Storage

// Store NFT metadata permanently
const metadata = {
  name: "My NFT",
  description: "A permanent NFT",
  image: "https://arweave.net/previous_image_tx_id",
  attributes: [...]
};

// Write to temp file and upload
fs.writeFileSync("/tmp/metadata.json", JSON.stringify(metadata));
const result = await uploadToArweave("/tmp/metadata.json");

// Use Arweave URL as NFT tokenURI
const tokenURI = `https://arweave.net/${result.arweave_tx_id}`;

Permissionless Token Listing

// Store token pair metadata for DEX listing
const pairMetadata = {
  baseToken: "0x...",
  quoteToken: "0x...",
  icon: "base64_image_data",
  description: "Trading pair info"
};

const result = await uploadToArweave(pairMetadataPath);
// Metadata now permanently accessible and verifiable

Document Archival

// Archive important documents permanently
const documents = ["contract.pdf", "agreement.pdf", "records.json"];

for (const doc of documents) {
  const result = await uploadToArweave(doc);
  console.log(`${doc} archived: https://arweave.net/${result.arweave_tx_id}`);
}

Error Handling

Common Errors

{sender}:{timestamp}

Error Response Format

{
  "error": "Invalid signature",
  "message": "The provided signature does not match the sender address"
}

Security Considerations

• Private Key Security: Never expose your

  ETH_PRIVKEY

  in client-side code
• Timestamp Validation: Always fetch fresh timestamps; stale ones are rejected
• Replay Protection: Timestamp in signature prevents replay attacks
• HTTPS: Always use HTTPS for API calls

Why Arweave Bridge?

The Problem

• Ethereum's original vision included Swarm for decentralized storage, but it was never implemented
• Users on L2s can't easily access permanent storage
• Requiring users to acquire AR tokens creates friction
• Filecoin exists but Arweave has better architecture for permanence

The Solution

• Pay with familiar stablecoins on zkSync
• No need to acquire or manage AR tokens
• Simple REST API with cryptographic authentication
• Permanent, immutable storage guarantees

Architecture

┌─────────────┐     ┌─────────────────────┐     ┌─────────────┐
│   User      │────▶│  Arweave Bridge     │────▶│   Arweave   │
│  (zkSync)   │     │  (Heroku Server)    │     │  (Storage)  │
└─────────────┘     └─────────────────────┘     └─────────────┘
      │                      │
      │ USDC/USDT/DAI       │ Manages allocations
      ▼                      │ Validates signatures
┌─────────────┐              │ Uploads to Arweave
│   Bridge    │◀─────────────┘
│   Address   │
└─────────────┘

Related Technologies

• Arweave: Permanent decentralized storage network
• zkSync: Ethereum Layer 2 scaling solution
• ZigZag Exchange: Native DEX on ZK Rollups
• ethers.js: Ethereum library for signing

Resources

• GitHub Repository
• ZigZag Exchange
• Arweave Network
• zkSync

Limitations

• Currently supports zkSync only (other L2s planned)
• Requires Node.js environment for the example code
• Server-side signing required (can't sign in browser without exposing private key)
• Hosted on Heroku (consider self-hosting for production)

Notes

• Allocation credits appear within 1-2 minutes of zkSync transaction
• Files are stored permanently on Arweave once uploaded
• The bridge is open source and can be self-hosted
• Timestamps must be current; the API rejects stale requests
• All uploads are verified via ECDSA signatures

Version History

• 1.0.0 (2026-01-10): Initial skill release
  • Complete API documentation
  • Node.js upload example
  • Authentication workflow
  • Use case examples
  • Error handling guide