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Introduction

Create, store, and verify location attestations on any blockchain.

Astral SDK is a developer-friendly TypeScript library that makes location-based attestations simple. Built on Ethereum Attestation Service (EAS), it supports both gasless offchain signatures and permanent onchain registration across multiple networks.

Quick Navigation​

→ Getting Started​

◆ Workflows​

§ Reference​

Why Astral SDK?​

→ Two ways to create location attestations​

  • Offchain: Gasless EIP-712 signatures, instant verification
  • Onchain: Permanent blockchain registration with smart contract integration

→ Supported location formats​

  • GeoJSON (Points, Polygons, Features) - ■ Available now
  • Decimal coordinates [lng, lat] - □ Coming soon
  • Well-Known Text (WKT) - □ Coming soon
  • H3 geospatial indexing - □ Coming soon

→ Multi-chain ready​

  • Sepolia (testnet) • Base • Arbitrum • Celo

→ Developer experience​

  • 100% TypeScript with full type safety
  • Clear workflow separation (no confusion)
  • Comprehensive docs and working examples

Installation​

pnpm add @decentralized-geo/astral-sdk  # or npm/yarn

30-Second Example​

import { AstralSDK } from '@decentralized-geo/astral-sdk';

// Connect to your wallet
const sdk = new AstralSDK({ 
  provider: window.ethereum,
  defaultChain: 'sepolia' 
});

// Create a location attestation
const attestation = await sdk.createOffchainLocationAttestation({
  location: [-0.163808, 51.5101], // London coordinates
  memo: 'Visited Big Ben today!'
});

// ✅ Done! You have a cryptographically signed location attestation
console.log('Attestation UID:', attestation.uid);

What's Next?​

  1. New to location attestations? Start with Core Concepts
  2. Want to build something? Try the Getting Started Guide
  3. Need reference docs? See the API Reference
  4. Looking for extensions? Check the Extensions Guide