Saved data and limits
Saved data
rstmqtt saves connection settings, payload view, publish history and window size and position.
On Linux, these live in $XDG_DATA_HOME/rstmqtt, or ~/.local/share/rstmqtt by default.
Passwords and received messages are never saved. Enter your password again after restarting. Received history clears when you close the app or start a new connection.
make uninstall removes the app, launcher entry and saved settings.
Limits
History has a budget. On a busy broker, older messages make room for new ones.
| What | Limit |
|---|---|
| Messages per topic | Last 100 |
| Memory for topics and messages | About 256 MiB; oldest messages across all topics are evicted first |
| Topic levels | 100,000 |
| Packet size | 16 MiB; outgoing MQTT 5 packets also respect the broker’s announced limit |
| Messages waiting to be sent | 1,024 |
| Topics, filters, client id, username, password, MQTT 5 property strings | 65,535 bytes each |
| Rendered text in the details panel | About 64 KiB, until Show all; see large payloads |
Messages that exceed the topic-level limit or cannot fit after eviction count as dropped in the status bar.
Hover for the reason.
An oversized incoming packet ends the session as Failed to avoid repeatedly fetching it on reconnect. If a retained message caused it, remove that message from the broker before reconnecting.