A minimal, cyberpunk Bitcoin block explorer written in Go. Served directly from a Bitcoin Core full node over JSON-RPC. No database, no indexer, no JavaScript framework — just your node and a single static binary.

Features

• Zero external dependencies beyond Bitcoin Core — no Electrum, no database
• Server-side rendered with html/template; no JavaScript
• Single binary — templates and CSS are embedded at compile time
• Per-network UI accent — mainnet green, testnet3 cyan, testnet4 amber, regtest purple
• LRU cache for immutable blocks and confirmed transactions
• Address scans with CSS-only progress bar and <meta> auto-refresh (no polling JS)
• Supports mainnet, testnet3, testnet4, regtest

Views

Route	Description
GET /	Overview — latest N blocks + chain summary
GET /block/:id	Block detail by hash or height
GET /tx/:txid	Transaction — confirmed or mempool, inputs/outputs, raw JSON
GET /address/:addr	Address validation + links to scans
GET /address/:addr/utxos	UTXO set scan with live progress bar
GET /address/:addr/history	Block filter tx history (requires blockfilterindex)
GET /node	Node info — version, connections, chain
GET /search	Routes height / hash / txid / address to the right view

Requirements

• Go 1.22+
• Bitcoin Core v25+ (v28+ for testnet4)
• blockfilterindex=1 in bitcoin.conf for address history scans
• txindex=1 optional — not required (verbosity-3 getrawtransaction provides prevouts)

Build

git clone https://github.com/alex27riva/mempunk
cd mempunk
make build

The version is read automatically from the current git tag (git describe --tags --always). Tag a release before building:

git tag v1.0.0
make build   # embeds "v1.0.0" in the binary

Without make, or on systems without make installed:

go build -ldflags "-X github.com/alex27riva/mempunk/internal/version.Version=$(git describe --tags --always)" -o mempunk ./cmd/mempunk

The binary embeds all templates and the stylesheet; no extra files needed at runtime.

Configuration

cp config.example.yaml config.yaml
$EDITOR config.yaml

Minimal config:

network: mainnet

rpc:
  host: "127.0.0.1"
  user: "bitcoin"
  password: "your-rpc-password"
  # or cookie auth:
  # cookie_file: "/home/bitcoin/.bitcoin/.cookie"

server:
  listen: "0.0.0.0:2100"

Every field can be overridden with a MEMPUNK_* environment variable:

MEMPUNK_RPC_PASSWORD=secret MEMPUNK_LOG_LEVEL=debug ./mempunk

Configuration reference

Key	Default	Description
network	mainnet	mainnet | testnet3 | testnet4 | regtest
rpc.host	127.0.0.1	Bitcoin Core RPC host
rpc.port	network default	8332 / 18332 / 48332 / 18443
rpc.user / rpc.password	—	RPC auth (mutually exclusive with cookie)
rpc.cookie_file	—	Path to .cookie file
server.listen	0.0.0.0:2100	HTTP listen address
log.level	info	debug | info | warn | error
log.format	text	text | json
explorer.latest_blocks	12	Blocks shown on the overview page
explorer.block_tx_details	true	Load full tx list on block pages
explorer.block_tx_page_size	200	Initial tx count per block page; "load more" doubles it
explorer.shorten_hashes	true	Show hashes as 00000000…392e92b5 in list views
explorer.cache_size	1000	LRU cache entries (0 = disabled)

Running

./mempunk
# or during development:
go run ./cmd/mempunk

mempunk verifies connectivity and chain on startup (getblockchaininfo + getnetworkinfo) and exits fast on misconfiguration.

By default it listens on 0.0.0.0:2100. To expose it publicly, put it behind a reverse proxy:

location / {
    proxy_pass http://127.0.0.1:2100;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
}

Running as a systemd service

Create /etc/systemd/system/mempunk.service:

[Unit]
Description=mempunk Bitcoin block explorer
After=network.target bitcoind.service
Wants=bitcoind.service

[Service]
Type=simple
User=mempunk
WorkingDirectory=/home/mempunk
ExecStart=/home/mempunk/mempunk
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target

Install and start:

# create dedicated user with home directory (matches RaspiBlitz conventions)
sudo useradd -m -s /usr/sbin/nologin mempunk

# install binary and config
sudo cp mempunk /home/mempunk/
sudo cp config.yaml /home/mempunk/
sudo chown -R mempunk:mempunk /home/mempunk

# enable and start
sudo systemctl daemon-reload
sudo systemctl enable --now mempunk

# check logs
sudo journalctl -u mempunk -f

Open the firewall port:

sudo ufw allow 2100 comment "mempunk HTTP"

If using cookie auth (recommended on RaspiBlitz), grant read access to .cookie and set the path in config.yaml:

sudo usermod -aG bitcoin mempunk

rpc:
  cookie_file: "/home/bitcoin/.bitcoin/.cookie"

bitcoin.conf

Recommended settings for full mempunk functionality:

server=1
rpcuser=bitcoin
rpcpassword=your-password

# required for address history scans
blockfilterindex=1

# optional — mempunk works without it
# txindex=1

Project layout

cmd/mempunk/          # entrypoint
internal/
  config/             # YAML config, env overrides, network params
  rpc/                # JSON-RPC client (read-only, 30s / 5min timeouts)
  cache/              # generic LRU cache
  version/            # build metadata (Version/GitCommit/BuildDate), set via ldflags
  explorer/           # RPC orchestration, view models, address scans
  handlers/           # thin Echo HTTP handlers
  render/             # Echo renderer backed by embedded templates
web/
  templates/          # html/template files (embedded)
  static/style.css    # cyberpunk stylesheet (embedded)
config.example.yaml

Tech stack

• Go — standard library + minimal deps
• Echo v4 — HTTP framework
• html/template — server-side rendering
• log/slog — structured logging
• embed — single binary, no external assets

License

MIT