Events

Events are the core unit of analytics in Emit Vision. Every captureEvent() call creates an event record with a name, properties, tags, and context — queryable in the dashboard.

Capturing an event

import { captureEvent } from "@emit-vision/sdk-js";
 
captureEvent("checkout_completed", {
  plan: "pro",
  seats: 5,
  billing: "annual",
});

Event naming conventions

Use snake_case with a verb_noun pattern. Consistent naming makes events easier to find and group in the dashboard.

Good	Avoid
`user_signed_up`	`UserSignedUp`, `signup`
`page_view`	`pageView`, `viewed page`
`checkout_completed`	`Checkout`, `done`
`button_clicked`	`click`, `btn_click`

Properties vs tags vs context

The captureEvent() signature accepts three distinct buckets for data:

captureEvent(
  "feature_enabled",
  { featureName: "dark-mode" },
  {
    tags: {
      experiment: "onboarding-v3",
      variant: "dark-first",
    },
    context: {
      route: "/settings",
      trigger: "toggle-switch",
    },
  },
);

Field	Purpose	When to use
`properties`	The event's own data	What happened: plan name, seat count, form values
`tags`	Indexed metadata for filtering	High-cardinality: feature flags, A/B variants, release channels
`context`	Ambient environment info	Where it happened: route, trigger, referrer

Put values you'll filter on frequently — feature flags, experiment variants — in tags. They're indexed differently and make dashboard queries faster.

Adding ambient context

Instead of repeating the same tags on every call, use setContext() and setTags() once:

import { setContext, setTags } from "@emit-vision/sdk-js";
 
// After login:
setContext({ userId: "user_123", orgId: "org_456" });
setTags({ plan: "pro", experiment: "new-nav" });
 
// Now every event automatically includes these
captureEvent("page_view", { path: "/dashboard" });

What you see in the dashboard

The Events tab shows a live stream of captured events. Each event shows:

Name and timestamp
Properties, tags, and context
User identification (if identify() was called)
Session link (if sessionId was set)
Release label (if release was set at init)

Querying events

The dashboard lets you filter events by name, property values, tags, user, session, release, and time range. Use the Explore view to build ad-hoc queries.

Reserved event names

Events starting with $ are reserved for internal SDK use:

Name	When it fires
`$flag_exposure`	After each `evaluateFlags()` call (can be disabled)
`$error`	Unhandled errors auto-captured by `autoCapture`
`$session_start`	First event in a session