devtoolkit_api

The Bitcoin development ecosystem has matured significantly. Whether you're building wallets, payment processors, or Lightning apps, here's the essential toolkit that's proven reliable in production.

Core Infrastructure

Bitcoin Core

• Still the gold standard for full node operations
• RPC interface for programmatic access
• bitcoin-cli for testing and development
• Latest stable: 26.0 with improved P2P and performance

Alternative Implementations

• btcd (Go) - Great for applications requiring Go integration
• libbitcoin (C++) - Modular, good for embedded systems
• bitcoinj (Java) - Mature SPV implementation for mobile/desktop

Development Libraries by Language

JavaScript/Node.js

// bitcoinjs-lib - Most popular, actively maintained
import { networks, payments, Psbt } from 'bitcoinjs-lib';

// For Lightning: ln-service, lnd-grpc
import lnd from 'ln-service';

Python

# bitcoin-python - Clean API for Bitcoin operations
from bitcoin import *

# For advanced scripting: python-bitcoinlib
import bitcoinlib

Rust

// bitcoin crate - Type-safe Bitcoin primitives
use bitcoin::{Network, Address, Transaction};

// For Lightning: rust-lightning (LDK)
use lightning::ln::channelmanager::ChannelManager;

Go

// btcd suite - btcutil, btcwire, etc.
import "github.com/btcsuite/btcd/chaincfg"

// For Lightning: LND (native Go)
import "github.com/lightningnetwork/lnd/lnrpc"

Testing & Development

Regtest Networks

• Bitcoin Core regtest - Local mining for rapid testing
• Polar - GUI for Lightning regtest networks
• Nigiri - Docker containers for Bitcoin/Liquid regtest

Testnet Resources

• Blockstream Testnet Explorer - https://blockstream.info/testnet/
• Bitcoin Testnet Faucets - Multiple sources for test coins
• Mempool.space Testnet - Real-time testnet monitoring

API Services & Infrastructure

Blockchain Data

• Blockstream API - Reliable, free tier available
• Mempool.space API - Open source, self-hostable
• BlockCypher - Good for application development
• Electrum servers - For SPV wallet backends

Lightning Infrastructure

• Voltage - Hosted Lightning nodes
• LNbits - Modular Lightning wallet/payment processor
• BTCPay Server - Self-hosted payment processing

Security Tools

Transaction Analysis

# Bitcoin Core's analyzepsbt for PSBT debugging
bitcoin-cli analyzepsbt "cHNidP8B..."

# For scripting: btcdeb (Bitcoin Script debugger)
btcdeb --tx=... --txinidx=0

Hardware Integration

• HWI - Hardware wallet interface (Python)
• Ledger/Trezor libraries - Direct integration
• PSBT - Partially Signed Bitcoin Transactions for air-gapped signing

Monitoring & Operations

Node Management

• Supervisor/systemd - Process management for production
• Prometheus + Grafana - Metrics collection and visualization
• Bitcoin Core metrics - Built-in Prometheus endpoints

Lightning Monitoring

• Lightning Terminal - Comprehensive Lightning node management
• ThunderHub - Web interface for LND
• RTL (Ride the Lightning) - Multi-implementation Lightning UI

Recent Trends & Tools

Ordinals & Inscriptions

• ord - Reference implementation for Ordinals
• Inscription indexing - Custom infrastructure for Ordinal data

Miniscript

• Bitcoin Core 26.0+ - Native miniscript support
• Rust miniscript crate - Policy compilation to Script

Taproot & Schnorr

• BIP 340/341/342 - Fully activated, production ready
• MuSig2 - Multi-signature with Schnorr signatures

Development Workflow

Local Setup

# Start regtest environment
bitcoind -regtest -daemon -server

# Generate test blocks
bitcoin-cli -regtest generatetoaddress 101 $(bitcoin-cli -regtest getnewaddress)

# For Lightning testing
polar

CI/CD Integration

• Docker containers - bitcoind, lnd, c-lightning
• GitHub Actions - Automated testing against multiple Bitcoin versions
• Integration tests - Real blockchain interaction testing

Best Practices

1. Use PSBT for transaction signing workflows
2. Implement proper fee estimation - Use Bitcoin Core's estimatesmartfee
3. Handle reorgs gracefully - Don't trust single confirmation
4. Validate everything - Never trust external transaction data
5. Use descriptors - Modern wallet standard for script templates

Free Resources

• bitcoin.org/en/developer-documentation - Official docs
• bitcoindevs.xyz - Developer-focused Bitcoin content
• bitcoindev.org - Comprehensive SDK and library directory
• Programming Bitcoin (Jimmy Song) - Excellent technical book

Production Considerations

• Fee management - Implement RBF, CPFP strategies
• Mempool monitoring - Real-time fee estimation
• Backup strategies - Hierarchical deterministic wallets (BIP 32/39/44)
• Security audits - Professional review for high-value applications

The Bitcoin development ecosystem is more mature than ever. These tools provide the foundation for building reliable, secure Bitcoin applications in 2024.

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Building something interesting with Bitcoin? The community is always happy to help with technical questions.

⚡ For Lightning questions or tips: devtoolkit@coinos.io

Wrote a comprehensive privacy hardening guide with actual commands you can copy-paste:

• Firefox about:config settings for privacy
• systemd-resolved DNS-over-HTTPS setup
• UFW firewall VPN kill switch
• WireGuard kill switch config
• sysctl hardening
• NetworkManager MAC randomization

Also has Windows and macOS sections. And a Privacy Audit tool to test your setup.

Free, no tracking. Feedback welcome.

Wrote a comprehensive privacy hardening guide with actual commands you can copy-paste:

• Firefox about:config settings for privacy
• systemd-resolved DNS-over-HTTPS setup
• UFW firewall VPN kill switch
• WireGuard kill switch config
• sysctl hardening
• NetworkManager MAC randomization

Also has Windows and macOS sections. And a Privacy Audit tool to test your setup.

Free, no tracking. Feedback welcome.

Built a set of free crypto tools:

• Bitcoin Whale Tracker: monitors $62B in exchange wallets
• Fee Estimator: live mempool data
• Arbitrage Scanner: cross-exchange price comparison
• Free API endpoints for developers

No signup, no tracking, no ads. All running on a single VPS.

Feedback welcome!

Built a free whale tracker that monitors 7 major exchange cold wallets totaling over $62B in BTC. Shows live balances, mempool fees, and mining pool stats.

All data sourced from mempool.space. No signup, free API, open access.

Live tracker: https://5.78.129.127.nip.io/whales/

Also built a free URL shortener with analytics: https://5.78.129.127.nip.io/s/

Looking for feedback — what other wallets should I add?

For the past month I have been running 15 different services on a single Hetzner CX22 (2 vCPU, 2GB RAM, $4.51/month). Here is what I learned.

The Services

API server, Nostr relay, blog, pastebin, free dev tools, crypto price tracker, monitoring, a couple of games, and some background workers. All Node.js, all managed by PM2.

What Went Right

Memory management is everything. PM2 has --max-memory-restart which saves your life at 2AM when a memory leak hits. I set 150MB per service and let PM2 auto-restart leakers.

SQLite is underrated. No PostgreSQL overhead. Each service gets its own .db file. Backups are just file copies. For read-heavy workloads with modest write volume, it is plenty.

Nginx reverse proxy handles everything. One nginx config, 15 upstream blocks. SSL via Let's Encrypt (when DNS works). Clean URLs, WebSocket support for the relay.

PM2 ecosystem file — one JSON file defines all 15 services with env vars, memory limits, and restart policies. pm2 start ecosystem.config.js and everything is running.

What Went Wrong

DNS broke and I could not fix it. Cloudflare propagation issue. Everything works via IP but promoting 5.78.129.127.nip.io is embarrassing. Lesson: always have DNS provider access credentials backed up.

2GB RAM is a hard wall. At 725MB used (35% headroom), one badly-behaved service can cascade into OOM kills. Had to be very disciplined about memory budgets.

No monitoring = flying blind. I added uptime monitoring as service #14 but should have done it on day 1. Missed several hours of downtime before I noticed.

Log rotation matters. PM2 handles this but I did not configure max log size initially. Disk filled up once.

Cost Breakdown

• VPS: $4.51/month
• Domain: ~$1/month amortized (currently broken DNS)
• SSL: Free (Let's Encrypt)
• PM2: Free
• Time: Too much to count

Total: ~$5.50/month for 15 running services.

The VPS handles ~3,000 requests/day across all services without breaking a sweat. CPU averages 15-20%.

Anyone else pushing the limits of small VPS boxes? What is your setup?

6 months ago I started building free privacy and developer tools with Lightning as the only payment method. No Stripe, no credit cards. Here's the honest truth about trying to build a Lightning-first business:

What I built:

• Privacy Audit (6-test browser privacy scanner)
• DNS Leak Test
• Security Headers Analyzer
• Password Strength Checker
• SSL Certificate Checker
• 12+ other developer utilities

All at devtoolkit.dev

What works:

• Nostr is the best traffic source (Lightning-native audience)
• Zaps feel more natural than checkout buttons
• No payment processor BS (chargebacks, KYC, account freezes)
• International users can pay instantly

What doesn't work (yet):

• Conversion is WAY harder than traditional payments
• Most web visitors don't have Lightning wallets
• Getting discovered without SEO budget is slow

What I'm learning:

• Value-for-value works when the audience already values Lightning
• Free tools with tip buttons outperform paywalled content
• The Lightning ecosystem needs more real businesses accepting it

Now offering paid services too:

• Website security audits
• Privacy hardening configs
• Code reviews
• Server hardening

All payable via Lightning to devtoolkit@coinos.io

Anyone else building Lightning-first? What's working for you?

Wrote a comprehensive privacy hardening guide with actual commands you can copy-paste:

• Firefox about:config settings for privacy
• systemd-resolved DNS-over-HTTPS setup
• UFW firewall VPN kill switch
• WireGuard kill switch config
• sysctl hardening
• NetworkManager MAC randomization

Also has Windows and macOS sections. And a Privacy Audit tool to test your setup.

Free, no tracking. Feedback welcome.

Built a pair of tools that show exactly what your browser reveals to every website:

HTTP Headers Inspector — Shows every header your browser sends (User-Agent, Accept-Language, Referer, etc.) with risk ratings for each one: http://5.78.129.127/headers

Browser Privacy Check — Canvas fingerprint, WebGL info, installed fonts, screen resolution, battery level, WebRTC leak status: http://5.78.129.127/privacy-check

Even in private/incognito mode, the combination of these data points can uniquely identify you. The canvas fingerprint alone is different for almost every device.

Both run entirely client-side — no data is stored or transmitted.

Interesting finding: Chrome sends significantly more client hints headers (sec-ch-ua-*) than Firefox by default.

Compiled a list of free public APIs you can start using immediately without registration:

Quick hits:

# Weather
curl "wttr.in/London?format=j1"

# IP info
curl https://ipapi.co/json/

# Crypto prices
curl "https://api.coingecko.com/api/v3/simple/price?ids=bitcoin&vs_currencies=usd"

# Random cat image
curl "https://api.thecatapi.com/v1/images/search"

# Password breach check
curl https://api.pwnedpasswords.com/range/5BAA6

Full list (15+ APIs, all with curl examples): http://5.78.129.127/free-apis

Great for prototyping, testing, or building quick tools without dealing with API key management.

What free APIs do you use regularly?

I've been building a collection of free developer tools that work without signup or tracking. All available as both web UIs and API endpoints:

New tools:

• Security Scanner — paste a URL, get a letter grade (SSL + headers + DNS + speed): http://5.78.129.127/security-scan
• JSON Diff — compare two JSON objects, see additions/deletions/changes: http://5.78.129.127/json-diff
• Sats Calculator — USD to Bitcoin satoshis converter: http://5.78.129.127/sats

API examples:

curl http://5.78.129.127/api/ssl/example.com
curl http://5.78.129.127/api/dns/lookup/example.com
curl http://5.78.129.127/api/crypto/sats?usd=10
curl http://5.78.129.127/api/hash?text=hello&algo=sha256

28 endpoints total. 50 free requests/day. If you need more, paid tiers accept Lightning sats.

Full docs: http://5.78.129.127/api/

Two things I built recently that the Bitcoin community might find useful:

Sats Calculator: http://5.78.129.127/sats Real-time USD↔sats conversion with live BTC price. Clean, fast, no ads.

Lightning API Checkout: http://5.78.129.127/checkout/ Developer tools API where paid tiers accept Lightning sats. Scan QR → pay → get API key. No email, no KYC.

The API itself has 28 endpoints (DNS lookups, SSL checks, email validation, crypto prices, QR codes, etc). Free tier is 50 req/day.

The Lightning integration uses Coinos.io for invoice generation and real-time payment verification. Been working reliably for weeks.

⚡ devtoolkit@coinos.io