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

# Changelog

> What's new in the Reactor SDKs and models.

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New releases, breaking changes, and notable improvements across the Reactor platform: JavaScript SDK, Python SDK, models, and API. Subscribe to updates in [Discord](https://discord.gg/tMcJM8N5N3).

<Update label="June 7, 2026" description="js-sdk · Multi-client connections">
  ### Breaking

  * **Publishing an input track is now explicit.** Output tracks still stream automatically on connect, but `sendonly` (input) tracks send nothing until your app calls [`publishTrack()`](/sdk-reference/reactor-class#publishtrack) (or renders [`<WebcamStream>`](/sdk-reference/react-components#webcamstream)). Apps that relied on input media flowing at connect must now publish explicitly once the connection is `ready`. See [Tracks](/concepts/tracks).

  ### New

  * **Output track pause/resume.** New [`pauseTrack()`](/sdk-reference/reactor-class#pausetrack) and [`resumeTrack()`](/sdk-reference/reactor-class#resumetrack) methods, plus an `autoResumeTracks` connect option (default `true`), control when each output track streams.
  * **Multi-client sessions.** A single session can now back several connections at once. `connect()` accepts `sessionId` and `connectionId` options to attach to a session or connection your backend created.
</Update>

<Update label="May 18, 2026" description="Pricing">
  ### Changed

  * **Per-second and per-hour pricing in dollars.** Model pricing is now displayed as US-dollar rates on the [Pricing & Billing](/resources/billing) page.
</Update>

<Update label="May 8, 2026" description="Docs · Pricing & billing">
  ### New

  * **Pricing & billing docs.** Published [Pricing & Billing](/resources/billing), covering session pricing, idle vs. active billing, and recoverable-state behavior.
  * **Beta status callouts.** Added a banner across docs and the [Overview](/overview) noting that Reactor is in beta. APIs and pricing may evolve.
</Update>

<Update label="April 21, 2026" description="Authentication · API">
  ### New

  * **Token TTL with `expires_after`.** Auth tokens now carry an `expires_after` field so clients can refresh proactively instead of waiting for a 401. See [Authentication](/authentication).
</Update>

<Update label="April 15, 2026" description="js-sdk · reactor-sdk · Concepts">
  ### New

  * **File uploads in the Python SDK.** `reactor-sdk` now supports `upload_file()` returning a `FileRef` that can be passed into `send_command()`.
  * **File uploads in the JavaScript SDK.** `uploadFile()` and `FileRef` are available in `@reactor-team/js-sdk` for passing files (images, audio, blobs) as command arguments.
  * **New concept page:** [File Uploads](/concepts/file-uploads) documents the upload-then-reference pattern in both SDKs.
</Update>

<Update label="March 29, 2026" description="API">
  ### Breaking

  * **Token endpoint is now POST.** The auth-token endpoint moved from `GET` to `POST` to allow request-body parameters. Update any direct API callers; the SDKs handle this automatically once upgraded.
</Update>

<Update label="March 26, 2026" description="js-sdk 2.7 · reactor-sdk 0.4">
  ### Breaking

  * **New SDK protocol.** Wire-level protocol overhaul shipped in `@reactor-team/js-sdk` 2.7 and `reactor-sdk` 0.4. Older SDK versions will no longer connect. Upgrade to the latest release.
  * **Removed `fetchInsecureToken()` and JWT helpers.** The development-only insecure token helpers were removed; all auth now flows through the standard token endpoint.

  ### Improved

  * **Maple theme refresh.** Docs site updated to Mintlify's Maple theme with Lucide icons, new codeblock styling, and refreshed colors.
  * **Navigation split** into separate "SDK" and "API Reference" tabs.
</Update>

<Update label="March 18, 2026" description="Helios">
  ### New

  * **Image conditioning for Helios.** `set_image()` accepts a reference image to steer generation, with cut or blend transitions for swapping mid-stream. See [Helios](/model-api-reference/helios/overview).

  ### Improved

  * Image size guidance clarified: 64KB limit with JPEG quality 0.5 recommended for set-image calls.
</Update>

<Update label="March 16, 2026" description="js-sdk 2.6.0">
  ### Breaking

  * **API renames in `@reactor-team/js-sdk` 2.6.0.** Several public methods and types were renamed for consistency with the Python SDK. Update import paths and call sites.
</Update>

<Update label="March 10, 2026" description="Helios">
  ### New

  * **Helios launch.** Reactor's first interactive real-time video generation model, built on a 14B-parameter Diffusion Transformer. Produces a continuous infinite stream you can steer with prompts and reference images.
  * **Helios prompt guide.** A dedicated [Prompt Guide](/model-api-reference/helios/prompt-guide) covering scene composition, transitions, and steering techniques.
</Update>

<Update label="March 1, 2026" description="Docs">
  ### Improved

  * **Renamed "Realtime AI" → "Realtime Video AI"** across the docs to better reflect what Reactor does. No API or SDK changes.
</Update>

<Update label="February 16, 2026" description="reactor-sdk (Python)">
  ### New

  * **Python SDK launched.** `reactor-sdk` is now available on PyPI, async-first, with parity for sessions, commands, and message handling. See [Using the SDK](/sdk-reference/using-the-sdk).
</Update>

<Update label="February 4, 2026" description="js-sdk">
  ### Breaking

  * **`sendCommand()` replaces `sendMessage()`.** The command API was renamed to clarify the distinction between commands (client → model) and messages (model → client). Update all `sendMessage` call sites. See [Commands and messages](/concepts/commands-and-messages).
  * **Removed message queueing.** Commands now have explicit `waiting` state instead of implicit queueing. Applications can decide whether to drop, replace, or buffer in-flight commands.
</Update>

<Update label="February 3, 2026" description="Authentication · API">
  ### Breaking

  * **JWT auth replaces `insecureApikey`.** All client connections now require a short-lived JWT minted server-side from your API key. The `insecureApikey` development flow is removed.
  * **New API Reference section.** Published a complete [API Reference](/sdk-reference/using-the-sdk) covering the `Reactor` class, React components, hooks, types, and events.
</Update>

<Update label="January 10, 2026" description="Docs">
  ### New

  * **Reactor docs site launched.** Initial release with [Overview](/overview) and [Quickstart](/quickstart). Ported from the legacy readme.io site.
</Update>