Summarize any blockchain transaction in plain English - no API keys, no LLM, pure pattern matching.
tx-summary decodes EVM transactions using known function selectors, contract registries, and token databases to produce human-readable summaries. It works entirely offline (aside from RPC calls) with zero external dependencies beyond a public RPC endpoint.
npx tx-summary 0x1234...abcd
# → "Swapped 1.50 ETH → 2,847.00 USDC via Uniswap V3"
# Or paste a block explorer URL directly
npx tx-summary https://etherscan.io/tx/0x1234...abcd
# → auto-detects chain, extracts hash, summarizes- Fetch — pulls the transaction and receipt from an RPC endpoint
- Decode — matches the 4-byte function selector against 60+ known signatures (swaps, transfers, lending, NFTs, etc.)
- Parse logs — extracts ERC20 transfers, NFT transfers (ERC721/1155) from event logs
- Identify contracts & tokens — looks up addresses in a registry of 150+ known contracts and 80+ tokens across 8 chains
- Summarize — applies heuristics (swap detection, mint/burn detection, lending flows) to produce a one-line summary
No LLM. No API keys. Deterministic output.
# Use directly with npx (no install needed)
npx tx-summary <hash-or-url>
# Or install globally
npm install -g tx-summary# Basic usage (defaults to Ethereum mainnet)
tx-summary 0x1234...abcd
# Paste a block explorer URL — chain is auto-detected
tx-summary https://arbiscan.io/tx/0x1234...abcd
tx-summary https://katanascan.com/tx/0x1234...abcd
tx-summary https://basescan.org/tx/0x1234...abcd
# Or specify chain manually
tx-summary 0x... --chain arbitrum
# Custom RPC (recommended for production)
tx-summary 0x... --rpc https://eth-mainnet.g.alchemy.com/v2/YOUR_KEY
# Verbose output (includes block, status, explorer link)
tx-summary 0x... --verbose
# JSON output (for scripting)
tx-summary 0x... --json| Chain | ID | Explorer URL Support | Default RPC |
|---|---|---|---|
ethereum |
1 | etherscan.io | Public Llama RPC |
arbitrum |
42161 | arbiscan.io | arb1.arbitrum.io |
optimism |
10 | optimistic.etherscan.io | mainnet.optimism.io |
base |
8453 | basescan.org | mainnet.base.org |
polygon |
137 | polygonscan.com | polygon-rpc.com |
zksync |
324 | era.zksync.network | mainnet.era.zksync.io |
katana |
747474 | katanascan.com | rpc.katana.network |
Each chain has multiple fallback RPCs configured. Pass --rpc to use your own.
tx-summary has deep integration with the Katana DeFi ecosystem:
Protocols:
- Sushi — V2/V3 routers, RouteProcessor swaps
- Morpho — Supply, borrow, repay, liquidate, flash loans
- Vault Bridge — Cross-chain token converters (WETH, USDC, USDT, WBTC)
- Agglayer — Unified bridge & Bridge-and-Call
Tokens:
- Native: KAT, AUSD (Agora USD)
- Bridged: WETH, WBTC, USDC, USDT, USDS
- Staking: wstETH, weETH, jitoSOL
- Universal: uSOL, uSUI, uADA, uXRP
- Swaps — Uniswap V2/V3, SushiSwap, 1inch, 0x, Cowswap, Curve, Balancer, Paraswap, KyberSwap, QuickSwap, SyncSwap
- Liquidity — Add/remove LP positions
- Lending — Aave V2/V3, Compound V3, Spark, Morpho Blue: supply, borrow, repay, liquidate, flash loans
- WETH — Wrap/unwrap operations
- Transfers — ETH/native + ERC20 sends with proper decimals
- Approvals — Token approvals with contract names
- Permit2 — Signature-based approvals
- ERC721 — Single NFT transfers, mints, burns, sales
- ERC1155 — Multi-token transfers
- Marketplaces — OpenSea Seaport, Blur, LooksRare, X2Y2, Sudoswap
- Contract deployments
- Bridge transactions (Across, Stargate, Hop, native L2 bridges)
- ENS registrations
- Failed transaction detection with error prefix
Sent 1.50 ETH → 0x1234…5678
Swapped 500.00 USDC → 0.25 ETH via Uniswap V3
Swapped 1.00 ETH → 2,847.00 USDC via 1inch V5 Router
Approved USDC for Uniswap Universal Router
Wrapped 2.00 ETH → WETH
Supplied 1,000.00 USDC to Aave
Borrowed 0.50 ETH from Aave
Repaid 500.00 DAI to Aave
Minted Bored Ape Yacht Club #1234
Bought Azuki #5678 for 15.00 ETH on OpenSea
Transferred CryptoPunks #9999 → 0xabc…def
Deployed new contract
Added WETH/USDC liquidity to Uniswap V2 Router
❌ FAILED: Swapped 100.00 USDC → 0.05 ETH via 0x Exchange Proxy
import { summarizeTx, getClient, decodeTx } from 'tx-summary';
// Simple summary
const result = await summarizeTx('0x1234...', { chain: 'ethereum' });
console.log(result.summary);
// → "Swapped 1.50 ETH → 2,847.00 USDC via Uniswap V3"
// Full result
console.log(result);
// {
// hash: '0x1234...',
// summary: 'Swapped 1.50 ETH → 2,847.00 USDC via Uniswap V3',
// from: '0xabc...',
// to: '0xdef...',
// status: 'success',
// blockNumber: 12345678n
// }
// Low-level: decode transaction data
const client = getClient('arbitrum');
const tx = await client.getTransaction({ hash: '0x1234...' });
const receipt = await client.getTransactionReceipt({ hash: '0x1234...' });
const decoded = decodeTx(tx, receipt);
console.log(decoded.transfers); // ERC20 transfers
console.log(decoded.nftTransfers); // NFT transfers
console.log(decoded.contractName); // Known contract namesrc/
├── cli.ts # CLI entry point (commander)
├── api.ts # High-level summarizeTx() function
├── chains.ts # Chain registry, RPC config, explorer URL parsing
├── decoder.ts # Tx decoding: selectors, contracts, tokens, log parsing
├── summarizer.ts # Rule-based summary generation
└── index.ts # Public API exports
The summarizer is entirely rule-based — it uses pattern matching on decoded function selectors and parsed event logs to generate summaries. No LLM or external API calls are involved.
MIT