> ## Documentation Index
> Fetch the complete documentation index at: https://docs.timeback.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Integration levels

> What Level 1 and Level 2 mean, what's required, and how review works

Timeback supports incremental integration. Start with Level 1 to get approved without rearchitecting your app. Each level unlocks more platform features and deeper integration with Timeback's learning systems.

## Overview

| Feature                            | Level 1 | Level 2 |
| ---------------------------------- | :-----: | :-----: |
| Launch and runtime support         |    ✔    |    ✔    |
| Core learning events (XP, mastery) |    ✔    |    ✔    |
| Rostering via OneRoster            |    ✔    |    ✔    |
| Staging and production credentials |    ✔    |    ✔    |
| Use Timeback placement data        |    ✗    |    ✔    |
| Use PowerPath learning engine      |    ✗    |    ✔    |
| Use QTI content formats            |    ✗    |    ✔    |
| Use Timeback spaced repetition     |    ✗    |    ✔    |

## Level 1: Minimal viable

Level 1 is the minimum viable integration. Your app works on the Timeback platform and follows the [non-negotiables](/beta/about-timeback/concepts/non-negotiables), but you keep your own learning engine, content formats, and algorithms.

### Technical requirements

| Requirement       | Description                                                                                           |
| ----------------- | ----------------------------------------------------------------------------------------------------- |
| App registration  | Register app via [first steps](/beta/build-on-timeback/first-steps)                                   |
| Rostering         | Student rostering via [supported session flows](/beta/build-on-timeback/sdk/identity)                 |
| Activity tracking | Record learning sessions via [Custom Activities](/beta/build-on-timeback/sdk/activity-tracking/intro) |

### Non-negotiable behaviors

These are tested during review. Apps that violate them will be rejected.

* XP reflects real learning minutes (1 XP = 1 minute of focused learning)
* No XP below 80% accuracy
* Mastery verified before advancement
* Learning events are complete and accurate

<Tip>
  Read [the full non-negotiables](/beta/about-timeback/concepts/non-negotiables) for the complete
  list.
</Tip>

### Not required at Level 1

You keep your own:

* Learning engine and algorithms (e.g. no [PowerPath](/beta/build-on-timeback/clients/powerpath))
* Content formats (e.g. no [QTI](/beta/build-on-timeback/clients/qti))
* Placement and diagnostic logic
* Spaced repetition implementation

## Level 2: Fully native

Level 2 apps use Timeback's learning systems instead of building their own. You read Timeback's placement data and act on it. You use our learning engine, content formats, and spaced repetition algorithms.

<Tip>
  **Building a new app?**

  <hr />

  If you are starting from scratch, [talk to us
  first](/beta/build-on-timeback/start-building/native-apps). We will share curriculum gaps and
  help you build for Level 2 from day one.
</Tip>

### What changes from Level 1

| Capability          | What it means                                                                               |
| ------------------- | ------------------------------------------------------------------------------------------- |
| Placement data      | Leverage Timeback's placement data                                                          |
| Learning engine     | Use [PowerPath](/beta/build-on-timeback/clients/powerpath) for sequencing and mastery logic |
| Content formats     | Store and retrieve content in [QTI](/beta/build-on-timeback/clients/qti) format             |
| Standards alignment | Align to curriculum standards via [CASE](/beta/api-reference/overview)                      |
| Spaced repetition   | Use Timeback's review scheduling algorithm                                                  |

### Why Level 2

* Don't reinvent placement, sequencing, or spaced repetition
* Your app automatically benefits from platform-wide improvements
* Deeper analytics and cross-app progress sharing

## What to expect during review

The Timeback team checks your app against the [non-negotiables](/beta/about-timeback/concepts/non-negotiables) and [Level 1 requirements](#level-1-minimal-viable).

| What we check        | How                                               |
| -------------------- | ------------------------------------------------- |
| XP policy adherence  | Verify awarded XP matches 1 XP = 1 focused minute |
| Accuracy gating      | Confirm no XP below 80% accuracy                  |
| Mastery verification | Check that advancement requires proof             |
| Event emission       | Validate Caliper events are complete and accurate |
| Launch compatibility | Test LTI launch and runtime behavior              |

If your app does not meet requirements, you receive specific feedback and can fix and resubmit.