🕹  arcade

A P2P-first Bitcoin transaction broadcast client for Teranode with Arc-compatible API

CI / CD		Quality
Security		Community

Project Navigation

📦 Installation	🚀 Quick Start	📚 Documentation
🐳 Docker Guide	☸️ Deployment Guide	🏗️ Architecture
🧪 Examples & Tests	⚡ Benchmarks	🛠️ Code Standards
🤖 AI Usage	📚 Resources	🤝 Contributing
👥 Maintainers	📝 License

📦 Installation

arcade requires a supported release of Go.

go get -u github.com/bsv-blockchain/arcade

🚀 Quick Start

Looking for per-network setup (mainnet / testnet / teratestnet / regtest)? See docs/getting-started.md.

Prerequisites

• Go 1.27+ (see go.mod for exact version)
• SQLite (included with most systems)
• Teranode broadcast URL (e.g., https://arc.taal.com)

Build from Source

git clone https://github.com/bsv-blockchain/arcade.git
cd arcade
go build -o arcade cmd/arcade/main.go

Configuration

Create config.yaml with your Teranode broadcast URL:

# Minimal working configuration with no dependencies
mode: all
network: main
storage_path: ~/.arcade

callback_url: "https://myhostname.com"

kafka:
  backend: memory
  consumer_group: arcade

store:
  backend: pebble
  pebble:
    path: ~/.arcade/pebble
    memtable_size_mb: 64
    l0_compaction_threshold: 4
    sync_writes: false

merkle_service:
  url: "https://merkle-service-us-1.bsvb.tech"

p2p:
  datahub_discovery: true

chaintracks_server:
  enabled: true

See config.example.yaml for all available options.

Run

arcade --config config.yaml

You should see output indicating the server is running on port 8080.

📚 Documentation

Overview

Arcade is a lightweight transaction broadcast service that:

• Registers transactions with Merkle Service
• Provides Arc-compatible HTTP API for easy migration
• Supports pluggable storage and event backends (in-memory)
• Tracks transaction status through the complete lifecycle
• Delivers notifications via webhooks and Server-Sent Events (SSE)

What is Teranode? Teranode is the next-generation BSV node implementation designed for enterprise-scale transaction processing. Arcade acts as a bridge between your application and the Teranode network, handling transaction submission and status tracking.

Features

• Arc-Compatible API - Drop-in replacement for Arc clients
• Chain Tracking - Blockchain header management with merkle proof validation
• Flexible Storage - Storage interface for different scaling needs
• Event Streaming - In-memory pub/sub for event distribution
• Webhook Delivery - Async notifications with retry logic
• [TODO] SSE Streaming - Real-time status updates with automatic catchup on reconnect
• Transaction Validation - Local validation before network submission
• Status Tracking - Complete audit trail of transaction lifecycle
• Extensible - All packages public, easy to customize
• API Reference – Dive into the godocs at pkg.go.dev/github.com/bsv-blockchain/arcade

API Usage

Submit Transaction (POST /tx)

curl -X POST http://localhost:3011/tx \
  -H "Content-Type: text/plain" \
  -H "X-CallbackUrl: https://myapp.com/webhook" \
  --data "<hex-encoded-transaction>"

Get Transaction Status (GET /tx/{txid})

curl http://localhost:3011/tx/{txid}

Health Check (GET /health)

curl http://localhost:3011/health

API Docs (GET /docs)

Interactive API documentation (Scalar UI) available at http://localhost:3011/docs

Transaction Status Flow

Client → Arcade
   ↓
RECEIVED (validated locally)
   ↓
SENT_TO_NETWORK (submitted to Teranode via HTTP)
   ↓
ACCEPTED_BY_NETWORK (acknowledged by Teranode)
   ↓
SEEN_ON_NETWORK (heard in subtree gossip - in mempool)
   ↓
MINED (heard in block gossip - included in block)

Or rejected:

REJECTED (from rejected-tx gossip)
DOUBLE_SPEND_ATTEMPTED (from rejected-tx gossip with specific reason)

Differences from Arc

• Simpler Deployment - Single binary with SQLite, no PostgreSQL/NATS required
• P2P-First - Direct gossip listening instead of node callbacks
• Teranode-Only - Designed for Teranode, no legacy node support
• Extensible - All packages public for customization

Configuration Reference

Required Fields

Field	Description	Default
teranode.broadcast_urls	Teranode broadcast service URLs (array)	Required

Optional Fields

Field	Description	Default
mode	Operating mode: embedded, remote	embedded
url	Arcade server URL (required for remote mode)	-
network	Bitcoin network: main, test, stn	main
storage_path	Data directory for persistent files	~/.arcade
log_level	Log level: debug, info, warn, error	info
server.address	HTTP server listen address	:3011
server.read_timeout	HTTP read timeout	30s
server.write_timeout	HTTP write timeout	30s
server.shutdown_timeout	Graceful shutdown timeout	10s
database.type	Storage backend: sqlite	sqlite
database.sqlite_path	SQLite database file path	~/.arcade/arcade.db
events.type	Event backend: memory	memory
events.buffer_size	Event channel buffer size	1000
teranode.datahub_urls	DataHub URLs for fetching block data (array)	-
teranode.auth_token	Authentication token for Teranode API	-
teranode.timeout	HTTP request timeout	30s
validator.max_tx_size_policy	Maximum transaction size (bytes); 0 tracks the network	0 (→ 10485760)
validator.max_script_size_policy	Maximum script size (bytes); 0 tracks the network	0 (→ 500000)
validator.max_tx_sigops_counts_policy	Maximum signature operations (0 = unlimited)	0
validator.min_fee_per_kb	Minimum fee per KB (satoshis); 0 tracks the network	0 (→ 100)
webhook.max_retries	Max webhook retry attempts	10
auth.enabled	Enable Bearer token authentication	false
auth.token	Bearer token (required if auth enabled)	-

Planned but not yet implemented:

• database.type: postgres - PostgreSQL storage backend
• events.type: redis - Redis event backend for distributed deployments

HTTP Headers

Arcade supports Arc-compatible headers:

• X-CallbackUrl - Webhook URL for async status updates
• X-CallbackToken - Token for webhook auth and SSE stream filtering
• X-FullStatusUpdates - Include all intermediate statuses (default: final only)
• X-SkipFeeValidation - Skip fee validation
• X-SkipScriptValidation - Skip script validation

Webhook Notifications

When you provide X-CallbackUrl, Arcade will POST status updates:

{
  "timestamp": "2024-03-26T16:02:29.655390092Z",
  "txid": "...",
  "txStatus": "SEEN_ON_NETWORK",
  "blockHash": "...",
  "blockHeight": 123456,
  "merklePath": "..."
}

Features:

• Automatic retries with linear backoff (1min, 2min, 3min, etc.)
• Configurable max retries via webhook.max_retries
• Every POST carries User-Agent: arcade-webhook/<version> — allowlist the arcade-webhook/ prefix at your edge so bot/WAF rules don't silently reject deliveries
• Delivery self-diagnosis: GET /tx/{txid}?callbackToken=<token> returns a callbacks array with attempts, lastAttemptAt, and lastResult ("delivered" or the last failure, e.g. "status 403") for your submissions — if attempts climbs while your endpoint sees nothing, something in front of it is rejecting the POSTs

SSE Streaming

Arcade provides real-time transaction status updates via SSE, offering an alternative to webhook callbacks.

How It Works

1. Submit Transaction with Callback Token:

   curl -X POST http://localhost:3011/tx \
     -H "Content-Type: text/plain" \
     -H "X-CallbackToken: my-token-123" \
     --data "<hex-encoded-transaction>"

2. Connect SSE Client:

   const eventSource = new EventSource('http://localhost:3011/events?callbackToken=my-token-123');
   
   eventSource.addEventListener('status', (e) => {
     const update = JSON.parse(e.data);
     console.log(`${update.txid}: ${update.status}`);
   });

3. Receive Real-Time Updates:

   id: 1699632123456789000
   event: status
   data: {"txid":"abc123...","status":"SENT_TO_NETWORK","timestamp":"2024-11-10T12:00:00Z"}
   

Catchup on Reconnect

When the SSE connection drops, the browser's EventSource automatically reconnects and sends the Last-Event-ID header. Arcade replays all missed events since that timestamp.

No client code needed - this is handled automatically by the EventSource API.

Event ID Format

Event IDs are nanosecond timestamps (time.UnixNano()), ensuring:

• Chronological ordering
• Virtually collision-free IDs
• Easy catchup queries by time

Use Cases

• Webhooks: Server-to-server notifications with retry logic
• SSE: Real-time browser updates with automatic reconnection
• Both: Use the same X-CallbackToken for webhooks AND SSE streaming

Filtering

Each SSE connection only receives events for transactions submitted with the matching callback token. This allows:

• Multiple users/sessions with isolated event streams
• Scoped access without complex authentication
• Simple token-based routing

See examples/sse_client.html and examples/sse_client.go for complete examples.

Remote Client

For applications that need Arcade functionality without running a full server, use the REST client:

import "github.com/bsv-blockchain/arcade/client"

c := client.New("http://arcade-server:3011")
defer c.Close() // Always close when done to clean up SSE connections

// Submit a single transaction
status, err := c.SubmitTransaction(ctx, rawTxBytes, nil)

// Submit multiple transactions
statuses, err := c.SubmitTransactions(ctx, [][]byte{rawTx1, rawTx2}, nil)

// Get transaction status
status, err := c.GetStatus(ctx, "txid...")

// Get policy configuration
policy, err := c.GetPolicy(ctx)

// Subscribe to status updates for a callback token
statusChan, err := c.Subscribe(ctx, "my-callback-token")
for status := range statusChan {
    fmt.Printf("Status: %s %s\n", status.TxID, status.Status)
}

Extending Arcade

All packages are public and designed for extension:

Custom Storage Backend

import "github.com/bsv-blockchain/arcade/store"

type MyStore struct {}

func (s *MyStore) GetOrInsertStatus(ctx context.Context, status *models.TransactionStatus) (*models.TransactionStatus, bool, error) {
    // Your implementation - returns (existing status, was inserted, error)
    // If transaction already exists, return existing status with inserted=false
}

// Implement other store.Store methods...

Custom Event Handler

import "github.com/bsv-blockchain/arcade/events"

type MyHandler struct {
    publisher events.Publisher
}

func (h *MyHandler) Start(ctx context.Context) error {
    ch, _ := h.publisher.Subscribe(ctx)
    for update := range ch {
        // Handle status update
    }
}

Troubleshooting

Server fails to start with "no teranodes configured"

• Ensure teranode.broadcast_urls is set in your config file with at least one valid URL

Transactions stuck in SENT_TO_NETWORK

• Check your Teranode broadcast URL is reachable
• Verify network connectivity and firewall rules

SQLite errors

• Ensure storage_path directory exists and is writable
• Check disk space availability

🏗️ Architecture

Key Components

• Arcade (arcade.go) - Core P2P listener that subscribes to block, subtree, and rejected-tx gossip topics
• Store (store/) - SQLite storage for transaction statuses and webhook tracking
• TxTracker (store/tracker.go) - In-memory index of transactions being monitored
• Event Publisher (events/) - In-memory pub/sub for distributing status updates
• Webhook Handler (handlers/webhook.go) - Delivers status updates with retry logic
• HTTP Routes (routes/fiber/) - Arc-compatible REST API including SSE streaming

Chain Tracking

Arcade uses go-chaintracks for blockchain header tracking and merkle proof validation. Headers are loaded from embedded checkpoint files on startup and updated via P2P block announcements.

For detailed architecture documentation, see doc.md.

🧪 Examples & Tests

All unit tests and examples run via GitHub Actions and use Go version 1.27.x. View the configuration file.

Run all tests (fast):

magex test

Run all tests with race detector (slower):

magex test:race

See examples/ for SSE client examples and the combined server example.

⚡ Benchmarks

Run the Go benchmarks:

magex bench

Note: Comprehensive benchmarks for P2P operations (peer discovery, message throughput, connection establishment) are planned for future releases. The current focus is on correctness and stability of the networking implementation.

🛠️ Code Standards

Read more about this Go project's code standards.

🤖 AI Usage & Assistant Guidelines

Read the AI Usage & Assistant Guidelines for details on how AI is used in this project and how to interact with AI assistants.

📚 Resources

• Architecture Documentation
• Observability — OTLP traces/metrics, structured log field canon, and transaction-lifecycle logging
• Teranode Documentation
• Arc API Reference

🤝 Contributing

View the contributing guidelines and please follow the code of conduct.

How can I help?

All kinds of contributions are welcome 🙌! The most basic way to show your support is to star 🌟 the project, or to raise issues 💬.

👥 Maintainers

Siggi	Dylan	MrZ

📝 License