⬡ Soroban Smart Block Explorer

Human-readable Soroban contract events on Stellar. Instead of raw XDR bytes, users see: "Address GABC… swapped 100 USDC → 98.7 XLM on StellarSwap at ledger #4521983."

---

The Problem

Stellar block explorers have excellent support for classic assets but poor support for Soroban smart contracts. When a user calls swap on a DEX, explorers show raw XDR bytes — unreadable to anyone. This "black box" experience dampens DeFi, NFT, and web3 growth on Stellar.

The Solution

Soroban Smart Block Explorer decodes contract calls on the fly using an ABI-like metadata registry, turning opaque XDR into plain English.

Before	After
AAAAA9hZ...[Raw XDR]...==	Address GABC… swapped 100 USDC → 98.7 XLM on StellarSwap at ledger #4521983

---

Architecture

┌─────────────────────────────────────────────────────────┐
│  Soroban RPC / Horizon                                  │
│  (getEvents, getTransaction)                            │
└────────────────────┬────────────────────────────────────┘
                     │ poll every 5 s
┌────────────────────▼────────────────────────────────────┐
│  Indexer  (Node.js)                                     │
│  • Fetches raw events via SorobanRpc.getEvents()        │
│  • Decodes XDR → human text using ABI registry          │
│  • Stores decoded events in PostgreSQL                  │
│  • Exposes REST API on :3001                            │
└────────────────────┬────────────────────────────────────┘
                     │ REST /api/*
┌────────────────────▼────────────────────────────────────┐
│  React Frontend  (Vite + TanStack Query)                │
│  • Home: paginated event feed + function filter         │
│  • /contract/:id — ABI metadata + event history        │
│  • /wallet/:address — wallet transaction history        │
│  • /event/:seq — full decoded event detail              │
└─────────────────────────────────────────────────────────┘
                     ▲
┌────────────────────┴────────────────────────────────────┐
│  Soroban Contract  (Rust)                               │
│  • ContractRegistry — stores ABI-like metadata          │
│  • EventDecoder — persists decoded events on-chain      │
└─────────────────────────────────────────────────────────┘

---

Quick Start

Prerequisites

• Rust + wasm32-unknown-unknown target
• Stellar CLI
• Node.js ≥ 20
• PostgreSQL

1. Clone & configure

git clone https://github.com/your-org/Soroban-Smart-Block
cd Soroban-Smart-Block
cp .env.example .env
# Edit .env with your RPC URL and DATABASE_URL

2. Build & deploy the contract

make build      # compile to WASM
make test       # run unit tests
make deploy     # deploy to testnet, prints CONTRACT_ID

Copy the printed contract ID into .env as EXPLORER_CONTRACT_ID.

3. Start the indexer + API

make indexer-install
make indexer

4. Start the frontend

make frontend-install
make frontend
# Open http://localhost:5173

Or run both together:

make install
make dev

---

Contract API

Function	Description
init(admin)	Initialise contract with admin address
register_contract(caller, contract_id, meta)	Register ABI metadata for a contract
update_contract(caller, contract_id, meta)	Update metadata (admin or registrant)
get_contract(contract_id)	Fetch contract metadata
submit_event(...)	Persist a decoded event (admin only)
get_event(seq)	Fetch event by sequence number
get_events(from, limit)	Paginated event list
event_count()	Total stored events

---

REST API

Endpoint	Description
GET /api/events?contract=&fn=&page=	Paginated event list
GET /api/events/:seq	Single event
GET /api/contracts/:id	Contract ABI metadata
POST /api/contracts	Register contract metadata
GET /api/wallet/:address	Wallet event history

---

SEP-41 Token Support

The decoder recognises SEP-41 token events (transfer, mint, burn) and formats amounts with the correct symbol, alongside classic Stellar assets fetched from Horizon.

---

Validated Need & Traction

• Confirmed gap: StellarExpert and Stellar.expert (the two primary Stellar explorers) show raw XDR bytes for all Soroban contract events as of May 2026 — no human-readable decoding exists.
• Community signal: Developers in #soroban-dev on Stellar Discord regularly ask how to inspect their own contract events in a readable form. No existing tool answers this.
• Comparable success: Etherscan's ABI decoder is one of its most-used features. Solscan built the same for Solana and became the primary explorer for Solana DeFi. Stellar has no equivalent for Soroban.
• Target users: Soroban dApp developers, DeFi users, NFT traders, auditors — anyone who needs to understand what is happening on-chain.

---

Detailed Architecture

┌──────────────────────────────────────────────────────────────┐
│  Stellar Network                                             │
│  ┌─────────────────────┐   ┌──────────────────────────────┐ │
│  │  Soroban RPC        │   │  Horizon API                 │ │
│  │  getEvents()        │   │  Classic asset metadata      │ │
│  │  getTransaction()   │   │  (asset codes, issuers)      │ │
│  └──────────┬──────────┘   └──────────────┬───────────────┘ │
└─────────────┼────────────────────────────┼─────────────────┘
              │ poll every 5 s             │ on-demand
┌─────────────▼────────────────────────────▼─────────────────┐
│  Indexer (Node.js)                                          │
│  ┌──────────────────────────────────────────────────────┐  │
│  │  decoder.js                                          │  │
│  │  scValToNative(topic/data) → match ABI registry      │  │
│  │  → "Address GA… swapped 100 USDC → 98.7 XLM"        │  │
│  └──────────────────────┬───────────────────────────────┘  │
│  ┌──────────────────────▼───────────────────────────────┐  │
│  │  db.js  (PostgreSQL)                                 │  │
│  │  events table  ·  contracts table                    │  │
│  │  indexes on contract_id, function, ledger            │  │
│  └──────────────────────┬───────────────────────────────┘  │
│  ┌──────────────────────▼───────────────────────────────┐  │
│  │  api.js  (Express REST)                              │  │
│  │  GET /api/events  ·  GET /api/contracts/:id          │  │
│  │  GET /api/wallet/:address  ·  POST /api/contracts    │  │
│  └──────────────────────────────────────────────────────┘  │
└─────────────────────────────┬───────────────────────────────┘
                              │ REST /api/*
┌─────────────────────────────▼───────────────────────────────┐
│  React Frontend (Vite + TanStack Query)                     │
│  /              — paginated feed, function filter           │
│  /contract/:id  — ABI metadata + event history             │
│  /wallet/:addr  — all events for a Stellar address         │
│  /event/:seq    — full decoded event detail                 │
└─────────────────────────────────────────────────────────────┘
                              ▲
┌─────────────────────────────┴───────────────────────────────┐
│  Soroban Contract (Rust)  — on-chain source of truth        │
│  ContractRegistry  register_contract / get_contract         │
│  EventDecoder      submit_event / get_events / event_count  │
└─────────────────────────────────────────────────────────────┘

Data flow for a decoded event:

1. Soroban contract emits an event (e.g., swap on StellarSwap)
2. Indexer fetches it via SorobanRpc.getEvents()
3. decoder.js calls scValToNative() on topics/data, looks up registered ABI
4. Produces human-readable string → stored in PostgreSQL + submitted to on-chain contract
5. Frontend queries REST API and displays the decoded event

---

SCF Submission Documents

Document	Description
ROADMAP.md	3-tranche milestone plan (MVP → Testnet → Mainnet)
BUDGET.md	Engineering hours and cost breakdown per tranche
TEAM.md	Team bios and qualification evidence
MANIFEST.md	Full project manifest
stellar.toml	SEP-1 compliant network info

---

Contributing

PRs welcome. Please open an issue first for large changes.

---

License

MIT