> ## Documentation Index
> Fetch the complete documentation index at: https://docs.getzenstep.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Pre-init Queue
> How Zenstep's call queue works — safe to call identify() and track() before the snippet has loaded.
## Overview
Zenstep uses a queue pattern (similar to the GA4 dataLayer) to handle calls made before the snippet bundle has evaluated. This means you can safely call `window.zenstep.identify()` and `window.zenstep.track()` anywhere in your page — even in `` scripts that run before ``.
***
## How it works
When the snippet's `
...
```
***
## Queue inspection
You can inspect the queue at any time via `window.zenstep._q`. Each entry is a tuple of `[methodName, argsArray]`:
```javascript theme={null}
console.log(window.zenstep._q);
// [["identify", ["user_123", { plan: "grow" }]], ["track", ["feature_used"]]]
```
After the snippet initialises, `_q` is an empty array (all calls have been replayed).
***
## Order guarantee
Calls are replayed in FIFO order. If you call `identify()` before `track()`, the queue processes them in that order. This matters because `track()` uses the identity set by the most recent `identify()` call.
***
## Edge cases
**Snippet fails to load** — if the CDN is unreachable, `snippet.js` never evaluates. Calls remain in `_q` but are never replayed. Your page continues to function normally — Zenstep fails silently.
**Multiple `identify()` calls** — if you call `identify()` twice before the snippet loads, both are queued. The second call merges attributes into the first (Zenstep does not replace the full identity object on re-identification).