> For the complete documentation index, see [llms.txt](https://docs.millimetric.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.millimetric.ai/readme.md).

# Welcome

Millimetric is a hosted analytics product where the **HTTP API is the source of truth**. You call it from your server, your browser, or an AI agent — every client speaks the same protocol.

## What you get

* **One HTTP API**, three first-class clients (browser SDK, Node SDK, MCP server for AI agents).
* **No cookies** — `anonymous_id` lives in `localStorage` and only when *you* call `track()`.
* **No raw IPs at rest** — IPs are HMAC'd with a daily-rotating salt; only country survives.
* **Smart attribution** — a server-side classifier separates Facebook *social* from Facebook *paid*, Google organic from Google Ads, and every other common combination, with a confidence label and an audit trail.
* **First-class MCP** — agents emit events with `track_event` and query their own data with `top_sources`, `get_stats`, `query_events`.

## Pick your path

| If you want to…                                                | Go here                                      |
| -------------------------------------------------------------- | -------------------------------------------- |
| See a working example in 60 seconds                            | [Quickstart](/quickstart.md)                 |
| Understand what an event is                                    | [Events](/core-concepts/events.md)           |
| Understand what to put in `properties`                         | [Properties](/core-concepts/properties.md)   |
| Stitch anonymous → known users                                 | [Identities](/core-concepts/identities.md)   |
| Know how Facebook *social* vs *paid* gets decided              | [Attribution](/core-concepts/attribution.md) |
| See exactly what gets stored                                   | [Privacy](/core-concepts/privacy.md)         |
| Reference every endpoint                                       | [API overview](/api-reference/overview.md)   |
| Drop the SDK into React / Next / Vue / Svelte                  | [Framework recipes](/sdks/frameworks.md)     |
| Connect an AI agent                                            | [MCP server](/mcp-for-ai-agents/overview.md) |
| Build a signup funnel, e-commerce dashboard, attribution model | [Recipes](/recipes/recipes.md)               |

## Three keys you'll meet everywhere

| Key prefix  | Where it lives                     | What it can do                   |
| ----------- | ---------------------------------- | -------------------------------- |
| `pk_live_…` | Browsers                           | Ingest only — origin-allowlisted |
| `sk_live_…` | Servers, scripts, anywhere private | Ingest only — full powers        |
| `rk_live_…` | Servers, MCP clients, dashboards   | Read only                        |

Mint them in the dashboard (`apps/web`). You'll see the secret exactly once.

## Send your first event

```bash
curl -X POST https://api.millimetric.ai/v1/track \
  -H "Authorization: Bearer sk_live_..." \
  -H "Content-Type: application/json" \
  -d '{
    "event": "signup",
    "anonymous_id": "u_abc",
    "user_id": "user_42",
    "properties": { "plan": "free" }
  }'
```

That's the whole API surface for ingest. Add `url` + `referrer` and the [classifier](/core-concepts/attribution.md) gives you `source / medium / campaign` for free.

The next thing to read is the [Quickstart](/quickstart.md), then [Events](/core-concepts/events.md) and [Properties](/core-concepts/properties.md) for the conceptual ground floor.


---

# Agent Instructions
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## Querying This Documentation
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