User ID Tracking

Embed one Proxyify key in your app and serve thousands of users — then see exactly who spent what, all from your dashboard.

Why you need this

A typical SaaS setup looks like this: you hold one Proxyify key on your backend, your app makes AI calls on behalf of many end-users, and you want to know per-user cost for billing, abuse detection, or debugging. Without user tracking, all requests look identical in the dashboard — you can only see aggregate usage.

With X-Proxyify-User-Id you get a per-user breakdown without managing a separate API key per user.

How it works

Add the header to every request your backend makes to Proxyify. Use whatever identifier you already use in your system — a database primary key, a UUID, or a hashed email.

http

POST /v1/chat/completions HTTP/1.1
Authorization: Bearer prx-...
Content-Type: application/json
X-Proxyify-User-Id: user_7a3f

{
  "model": "openai/gpt-4o",
  "messages": [{ "role": "user", "content": "Hello" }]
}

Proxyify reads the header, stores it as end_user_id on every log entry, and never forwards it to the upstream provider.

Code examples

python

import requests

def chat(user_id: str, message: str):
    return requests.post(
        "https://proxyify.dev/v1/chat/completions",
        headers={
            "Authorization": "Bearer prx-...",
            "Content-Type": "application/json",
            "X-Proxyify-User-Id": user_id,   # e.g. str(request.user.pk)
        },
        json={
            "model": "openai/gpt-4o",
            "messages": [{"role": "user", "content": message}],
        },
    ).json()

javascript (node)

async function chat(userId, message) {
  const res = await fetch("https://proxyify.dev/v1/chat/completions", {
    method: "POST",
    headers: {
      "Authorization": "Bearer prx-...",
      "Content-Type": "application/json",
      "X-Proxyify-User-Id": userId,
    },
    body: JSON.stringify({
      model: "openai/gpt-4o",
      messages: [{ role: "user", content: message }],
    }),
  });
  return res.json();
}

Viewing in the dashboard

Go to Dashboard → Usage. Every log row shows a User ID column:

If no User ID was sent — the cell shows —
If a User ID was sent — it appears as a clickable blue badge
Clicking the badge instantly filters the log table to show only that user's requests
You can also type a User ID directly into the End-User ID filter field
The Export CSV button respects the current filter — export all requests for a single user with one click

Rules & limits

Property	Value
Header name	`X-Proxyify-User-Id`
Max length	255 characters (truncated silently if longer)
Allowed characters	Any printable string — UUID, integer, slug, hashed email
Optional?	Yes — omitting it never causes an error
Forwarded upstream?	No — Proxyify strips it before forwarding
Applies to	All modalities: text, image, video, STT, TTS

Security note

The User ID is a label you assign — Proxyify does not verify or authenticate it. Never use raw user-supplied input (e.g. request.GET["user_id"]) as the header value without sanitising it first. Use your own internal identifier (a database PK or a server-signed token) to prevent spoofing.