ZMQ Notifications

tidecoind can publish block and transaction notifications over ZeroMQ. ZMQ is useful for exchanges, explorers, indexers, and monitoring services that should react to new events without polling RPC constantly.

This page summarizes ../tidecoin/doc/zmq.md.

Build and Enable

ZeroMQ support must be built in:


cmake -B build -DWITH_ZMQ=ON

Then enable topics in tidecoin.conf or on the command line:


zmqpubrawblock=tcp://127.0.0.1:28332
zmqpubrawtx=tcp://127.0.0.1:28333
zmqpubsequence=tcp://127.0.0.1:28334

Topics

Option	Topic	Body
`-zmqpubrawtx=<address>`	`rawtx`	Serialized transaction
`-zmqpubhashtx=<address>`	`hashtx`	Reversed 32-byte transaction hash
`-zmqpubrawblock=<address>`	`rawblock`	Serialized block
`-zmqpubhashblock=<address>`	`hashblock`	Reversed 32-byte block hash
`-zmqpubsequence=<address>`	`sequence`	Block connect/disconnect and mempool add/remove events

Every message has three parts:


topic | body | 4-byte little-endian sequence number

Use the sequence number to detect missed notifications.

Sequence Topic Events

Event marker	Meaning
`C`	Block connected
`D`	Block disconnected
`A`	Transaction added to mempool
`R`	Transaction removed from mempool for a non-block reason

For block topics, reorganizations require the subscriber to query the node and walk from its last known block to the new tip.

High Water Mark

Each notification type supports an outbound high-water-mark option:


zmqpubrawtxhwm=10000
zmqpubrawblockhwm=10000

Tune HWM values for indexers and exchanges that may briefly fall behind. ZMQ can drop messages under pressure; subscribers must detect gaps and repair from RPC.

Security

ZMQ has no authentication or authorization at the Tidecoin topic layer. Bind it to localhost or a trusted network only. Treat all received data as untrusted until validated through your node or indexer.