Tags & Context

setTag#

function setTag(
  key: string,
  value: string | number | boolean,
): void;

Set a single tag. The tag is attached to every event sent from this point on.

import { setTag } from '@reliableapp/frontend-core';

setTag('plan', 'pro');
setTag('region', 'us-east-1');
setTag('app_version', '2.4.0');

setTags#

function setTags(
  tags: Record<string, string | number | boolean>,
): void;

Merge-set multiple tags at once. Equivalent to calling setTag for each key, but cheaper:

import { setTags } from '@reliableapp/frontend-core';

setTags({
  plan: 'pro',
  region: 'us-east-1',
  app_version: '2.4.0',
  experiment_cohort: 'B',
});

Lifecycle#

Tags persist for the lifetime of the session — they're attached to every event sent until either:

• The page is reloaded (a new session starts)
• The user is identified with a different externalId (session rotates)
• You overwrite the tag with a new setTag call (same key, new value)

Per-event tags#

For tags that apply to a single event only, pass them via captureException or captureMessage options. Per-event tags are merged over scope tags, with per-event values winning on conflict:

setTag('flow', 'general');

captureException(err, {
  tags: { flow: 'checkout' }, // overrides 'general' for this event only
});

// Subsequent events still see flow='general' from scope

Naming conventions#

Tag keys aren't enforced, but a few conventions make dashboard filtering pleasant:

• Use snake_case for keys — consistent with the rest of the API.
• Keep values short — they're rendered as filter chips in the UI.
• Use stable values, not unique IDs — tags are for grouping. Put unique values (user IDs, request IDs) in traits on identify, or in event-specific data.