Run a testnet node

You can either download a pre-built binary or build from source (Build from source).

Download a pre-built binary

# Linux example
curl -L -o coincync-node \
  https://coincync.network/release/v1.0.1-testnet/coincync-node-linux-x86_64
chmod +x coincync-node
./coincync-node --network testnet --data-dir ~/.coincync

Where to run a node, where NOT to mine: running a coincync-node (P2P relay, RPC, no PoW computation) on a cloud VPS is fine. Mining is different — DigitalOcean, Cloudflare, AWS, GCP, and most major hosting providers explicitly prohibit cryptocurrency mining in their TOS and will terminate accounts that compute PoW. Run coincync-miner / coincync-tui-miner on personal hardware (your laptop, desktop, or a server you physically own). RandomX is CPU-only by design specifically so home machines can secure the chain — that’s the architecture, not a workaround.

Quick start

./coincync-node --network testnet --data-dir ~/.coincync

That’s it. The node will:

1. Open (or create) a RocksDB database under ~/.coincync/testnet/
2. Initialize the genesis block if the database is empty (and verify its hash against the hardcoded constant in src/testnet.rs)
3. Start the P2P listener on 0.0.0.0:28080
4. Start the JSON-RPC server on 127.0.0.1:28081
5. Connect to the public testnet seed nodes and begin syncing

Stop the node with Ctrl-C. Restart it later — chain state is on disk; it picks up where it left off.

What success looks like

The first ~30 seconds of log output should look something like this:

INFO  CoinCync 1.0 node starting
INFO  Network:  Testnet
INFO  Data dir: "~/.coincync"
INFO  Opening database at "~/.coincync/testnet"
INFO  Chain tip: height=0, hash=41f970df
INFO  Starting P2P listener on 0.0.0.0:28080
INFO  Starting RPC server on 127.0.0.1:28081
INFO  RPC server bound, methods: get_info, get_blockchain_info, ...
INFO  Connected to seed1.coincync.network:28080
INFO  Sync started — target height 12345
INFO  Node is running. Ctrl-C to stop.

If you see CRITICAL: Genesis hash mismatch! instead, your build is corrupt or you modified src/testnet.rs without recomputing the hash. Don’t ignore that error — it means the binary you built will fork off the live testnet on the very first block.

Talk to the running node

In a second terminal:

# How's the chain tip?
curl -sX POST http://127.0.0.1:28081 \
     -H 'content-type: application/json' \
     -d '{"jsonrpc":"2.0","id":1,"method":"get_info"}' | jq .

# Block at a specific height
curl -sX POST http://127.0.0.1:28081 \
     -H 'content-type: application/json' \
     -d '{"jsonrpc":"2.0","id":1,"method":"get_block_by_height","params":[100]}' | jq .

# Mempool stats
curl -sX POST http://127.0.0.1:28081 \
     -H 'content-type: application/json' \
     -d '{"jsonrpc":"2.0","id":1,"method":"get_mempool_info"}' | jq .

The full method inventory is in JSON-RPC reference.

Common CLI flags

Networks

Try the local explorer

If you want to see the block explorer alongside your node, pass --explorer:

./target/release/coincync-node --network testnet --explorer

Then visit http://127.0.0.1:28083/ in your browser. Localhost-only by default — nobody on the LAN or the public internet can see it. This is for local development only; for a public block explorer use the standalone Caddy stack in /deploy/explorer/.

Operating a public seed (operators)

If you run infrastructure that should accept inbound peers: open TCP 28080 in your cloud firewall (not only the host), install coincync-node under systemd, and verify DNS/TCP health. Broader deployment notes are in Deploying a node. In the source tree, scripts live under deploy/ops/ (README): install-testnet-node.sh, verify-community-bootstrap.sh, plus scripts/verify-community-join-readiness.ps1 on Windows.

Next steps

• Create a wallet — generate a seed phrase, derive an address, receive testnet CYNC from the faucet
• Deploying a node — systemd unit, docker compose, firewall rules, monitoring
• JSON-RPC reference — every method the node exposes, with sample requests