Every report carries a single chronological chain. Lifecycle, tap and native log entries are automatic; console and navigation are integrations you add (see Console and Screen tracking); custom entries are yours.
{
"t": 1765800000123,
"seq": 42,
"kind": "network",
"level": "error",
"message": "POST /api/cart",
"data": {
"reqId": 17,
"status": 500
}
}Kinds
| Kind | Recorded when |
|---|---|
navigation | A screen transition — only once wired. |
tap | The user touches the screen. Captured at the window level, so React Native touchables count. |
console | Your JS logs — only with the console integration added. |
network | Not captured on React Native — see Console & network. |
lifecycle | The app backgrounds, foregrounds, or resumes. |
error | A native exception below the bridge. An uncaught JS error becomes a report instead — see Crash reporting. |
custom | You called addBreadcrumb. |
Adding your own
const { addBreadcrumb } = useTraceItX();
addBreadcrumb({
message: 'Coupon applied',
kind: 'custom',
level: 'info',
data: { code: 'SUMMER25', discount: 0.25 },
});addBreadcrumb never throws. An unknown kind coerces to custom and an
invalid level is dropped rather than passed through — instrumentation must not
be able to break the app it is instrumenting.
Put identifiers in data, not in message. data survives as structured
fields; message is prose, and prose is truncated first.
Crossing the bridge
Crumbs added from JS are forwarded to the native buffer, which is where the chain actually lives — the same buffer the crash reporter reads when it builds an unattended report. That is why such a report still carries the trail that led to it.
The cost is that a crumb added in the same tick as a hard crash may not make the crossing. Rare, and the alternative — keeping the chain in JS — loses the whole trail on every native crash instead of the last entry on some.
The shared clock
t is absolute epoch milliseconds, on the same clock as the session replay, so
a viewer can line a crumb up against the frame on screen when it fired. seq
breaks ties inside the same millisecond.
Limits
Caps and trimming behaviour are in Errors & limits.