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Errors

The Errors page groups exceptions thrown by your driver so you can focus on unique issues rather than wading through duplicates. Each error group shows how often it occurs, when it was last seen, and a trend sparkline.

Errors page showing grouped errors with counts and sparklines

Error Groups​

Errors are automatically grouped by their fingerprint (see Error Grouping for details). The error list shows:

  • Type and Value — the error type (e.g. LuaError) and the error message
  • Count — total number of occurrences
  • Last Seen — when the error last occurred (hover for full timestamp)
  • Age — how long ago the error was first seen
  • Trend — a sparkline showing occurrence frequency over the last 24 hours

This lets you quickly see which errors are frequent, which are new, and which are trending up or down.

Error Detail​

Click an error group to open the detail page.

Error detail page showing stack trace, occurrences, and metadata

This gives you everything you need to diagnose the issue:

Stack Trace​

A formatted, syntax-highlighted view of the call stack showing file names, line numbers, and function names. If you've uploaded source maps, the stack trace maps back to your original source files rather than the bundled output.

Occurrences​

A table of every individual occurrence of this error, showing:

  • Error ID — unique identifier (click to view that specific occurrence)
  • Timestamp — when it happened
  • Message — the error message for this occurrence
  • Version — the driver version that produced it

Navigate between occurrences using the Previous / Next buttons, or jump to the first or last occurrence.

Info​

Metadata about the error group:

  • Affected versions — which driver versions have produced this error
  • Affected controllers — which controllers it's occurred on
  • Affected drivers — which drivers it's appeared in
  • Event name — the handler that was executing when the error occurred

Context​

Expandable sections showing:

  • Tags — key-value pairs attached to the error
  • Context data — full JSON payload from the error context
  • Grouping info — the fingerprint strategy, hash, and raw grouping data used to identify this error group

Histogram​

A bar chart above the error list shows error volume over time. Hover for counts at each time bucket. The histogram adjusts automatically based on the selected time range.

Real-Time Streaming​

New errors stream in via WebSocket. When a new occurrence of an existing error arrives, the group's count, last seen, and sparkline update in place. New error groups appear at the top of the list.

The same pause/resume controls from Events and Logs are available — pause the stream to inspect, and a badge shows how many errors are buffered.

Automatic Capture​

Errors in event handlers are captured automatically. You don't need to add any error handling code — just add the Anvil SDK and errors appear in Anvil.

Note that errors in C4:SetTimer and C4:url() callbacks need manual instrumentation because C4 is a protected userdata object. See Manual Capture for details.

Keyboard Navigation​

  • j / k — move down / up through error groups
  • Enter — open the selected error's detail page