Octa Engineering Notes                                   Christian Elías
Request for Comments: OCTA-6                                   octa.page
Category: Informational                                         May 2026


                  av.js — self-hosted analytics embed

Abstract

   API reference for av.js: the minimal analytics snippet for
   Avelor-hosted projects. Covers the embed pattern, the pageview
   payload structure, custom event API, session ID strategy, and
   implementation constraints like keepalive fetches and localhost
   filtering.

Status of This Memo

   This memo documents notes notes for the Internet community. It does
   not specify an Internet standard of any kind. Distribution of this
   memo is unlimited. The canonical version lives at
   https://octa.page/doc/av-js-analytics-embed/ and the machine-readable
   source at https://octa.page/doc/av-js-analytics-embed.md

   "av.js" is a minimal analytics snippet that reports pageviews and
   custom events to "analytics.avelor.es/collect". Drop a "<script>"
   tag, set "data-project", done.

1.  Embed

   <script src="https://analytics.avelor.es/av.js" data-project="project-slug"></script>

   "data-project" is required — without it the script exits immediately.
   Requests from "localhost", "127.0.0.1", and "::1" are also silently
   skipped.

2.  What it sends on load

   A "POST /collect" with:

   {
     "project_id": "project-slug",
     "url": "/path?query",
     "referrer": "https://example.com",
     "session_id": "lxk3r2abc9d"
   }

   "session_id" is generated once per tab and stored in "sessionStorage"
   under "_av_sid". It survives navigation within the tab but not across
   tabs or sessions.

3.  Custom events

   window.avelor.track('event-name', { key: 'value' });

   Event name is truncated to 100 chars. "properties" is a free-form
   object or "null". Full payload:

   {
     "type": "event",
     "project_id": "project-slug",
     "session_id": "lxk3r2abc9d",
     "name": "click-cta",
     "url": "/",
     "properties": { "variant": "A" }
   }

4.  Implementation notes

   o  "keepalive: true" on the fetch call — the request survives page
      navigation, so events sent just before a redirect are not lost.
   o  "credentials: 'omit'" — no cookies or auth headers sent to the
      collector.
   o  Network errors are swallowed — a dead collector does not break the
      host page.


Christian Elías              Informational                      [Page 1]