oix: Open WebUI SDK

A Python SDK for building apps for Open WebUI, with authenticated events and a signed API client.

Requires Python 3.11+ and Open WebUI with Apps support.

Install

python -m pip install oix

A minimal app

from oix import App

app = App(
    manifest_id="hello",
    name="Hello",
    scopes=["channels:messages:read", "channels:messages:write"],
)


@app.on("channel.message.created")
async def hello(event):
    if event.content == "hello":
        await event.reply("Hello!")


if __name__ == "__main__":
    app.run()

manifest_id identifies your app in its manifest. WebUI assigns a separate app_id to each installation; incoming events and their clients already carry that ID.

Save the example as app.py. Generate an Ed25519 key and an API key, then start the app:

umask 077
openssl genpkey -algorithm ED25519 -out app-private-key.pem
export APP_PRIVATE_KEY_FILE="$PWD/app-private-key.pem"
export API_KEY="$(python -c 'import secrets; print(secrets.token_urlsafe(32))')"
python app.py

The app listens on port 8000 at /events. Use app.run(port=8001, path="/manifest") to change these. Press Ctrl+C to stop it.

Keep both secrets in persistent deployment storage and reuse them across restarts. The SDK reads API_KEY and the PEM file at APP_PRIVATE_KEY_FILE. Explicit api_key and PEM private_key arguments override these defaults. Missing or invalid credentials fail at construction; startup never generates credentials.

In WebUI, enable Apps, add your public HTTPS event URL and the API key, approve the scopes, then connect. Invite the app into a channel. GET on the event URL provides the manifest; POST receives authenticated events.

Pass manifest=False to app.run() for a POST-only endpoint and enter the app details manually in WebUI. app.manifest supplies those details.

For localhost development, pass the exact WebUI origin in allowed_private_origins=("http://127.0.0.1:8080",). Configure WebUI's APP_ALLOWED_PRIVATE_ORIGINS to allow your app origin. Production callbacks require HTTPS and public destinations by default.

Events and replies

Register async handlers with @app.on(...) for:

• channel.mention: explicit app mentions; text is in event.data["text"].
• channel.action: a saved message button; event.data contains message_id, action_id, and context.
• channel.operation.status: a status request for deferred work.
• channel.message.created, channel.message.updated, channel.message.deleted: ordinary channel events, including messages without mentions. Request channels:messages:read for these.

All callbacks receive one event. Its event.client is bound to the originating instance and installation, and is excluded from event serialization. Events are verified against the originating WebUI before your handler runs. For interactions, the actor's admin status reflects their current authorization. Ordinary message events do not authorize commands on behalf of their authors.

For mentions, actions and operation-status handlers, return a string or AppChannelReply(content="...") for an inline private reply, or set visibility="channel" to post publicly in the channel. AppChannelReply also supports update, download, error, and deferred. Action(action_id="...", label="...", context={...}) buttons are supported only on saved channel messages. Button handlers must enforce any operation-specific rules themselves.

Return AppChannelReply(type="deferred", operation_id=event.id) for background work and implement a channel.operation.status handler. Keep status replies private. Your app manages workers, job storage, and restart recovery. Recheck await event.client.authorize(event.execution_token) before later sensitive work, and apply your app's own permissions.

Ordinary channel-event handlers return None. Use await event.send("...") to post in the current channel or await event.reply("...") to reference the source message. Both preserve its existing thread; replying to a top-level message stays top-level. Both require write access and accept actions=[...]. Deleted messages and events without a source message cannot be replied to.

event.content contains created/updated message content or the original mention text, unchanged. event.channel_id, event.message_id and event.parent_id use verified source information. The original actor, channel, message, data and token fields remain available.

Ordinary events are acknowledged after verification, then handlers run in background tasks. max_concurrency=32 bounds verification and ordinary handlers together; overload returns HTTP 503 without queuing or retries. Acknowledged work does not survive a process crash. Delivery is best effort, can arrive out of order, and has no replay guarantee. Keep durable work in your own job storage.

Self-authored message events are ignored by default for the current installation. Pass ignore_self_events=False to receive them. Other apps and model messages are not filtered. A mention can produce both a channel event and a mention interaction.

Interactions have a 2.5-second processing budget, including at most two seconds for verification. Ordinary verification has eight seconds; acknowledged handlers have no HTTP deadline. Timeout cancellation does not undo external side effects. Return a deferred reply for longer interactions.

Route buttons by exact action ID:

from oix import AppChannelReply


@app.action("cancel_publish")
async def cancel(event):
    return AppChannelReply(
        type="update", visibility="channel", content="Publishing cancelled."
    )

An exact action handler overrides the generic channel.action handler; only one runs. Register async handlers accepting one event. Duplicate registrations and unknown event names fail immediately.

Scopes

Apps request scopes in their manifest. Admins choose which to grant and can change that selection in app settings. Channel access also requires an invitation to the channel.

• channels:mentions:read: receive explicit app mentions, without message history.
• channels:messages:read: receive message events, read history and thread replies, and receive mentions.
• channels:messages:write: send messages and edit the app's own messages, including public callback replies.
• channels:read: list joined channels and their details, without messages.

Write access does not grant read access. Private replies do not require write access.

Runtime client

message = await event.client.create_message(
    event.channel_id, content="Working on it...", parent_id=event.parent_id
)
await event.client.update_message(message["id"], content="Done.", etag=message["etag"])

Content and actions are replacement values when editing. Omitted actions become an empty list; include any buttons you want to retain. AppChannelMessage remains exported for independent validation.

Available methods: get_me(), list_channels(), list_messages(channel_id, limit=50, before=None, parent_id=None), create_message(...), update_message(...), authorize(execution_token), and verify_event(event_token). Responses are WebUI JSON dictionaries/lists. APIError.status exposes HTTP failures, including 412 for stale edits. method, path and detail provide request context and at most 64 KiB of response detail, without authorization headers. Transport failures use aiohttp exceptions or TimeoutError. Message creation is never automatically retried.

One App can serve multiple independent WebUI instances. Each event supplies its WebUI origin and local installation ID; its client is bound to that pair. For proactive messages, save the destination URL and app ID alongside your subscription, then call app.client(webui_url, app_id) after restart. API-key holders are trusted to connect instances; a shared key does not provide tenant-specific business authorization.

Existing web servers

To mount the app in FastAPI, install oix[fastapi] and include its router:

from fastapi import FastAPI
from oix.fastapi import create_router

server = FastAPI()
server.include_router(create_router(app, path="/events"))

Run your existing server instead of calling app.run(). The router also accepts manifest=False. Its shutdown lifespan composes with your application's lifespan, including existing workers.

For another web framework, call app.authenticate(authorization) before reading a body, enforce a 1 MiB body limit while streaming, parse JSON, then await app.handle_event(payload, authorization=authorization). Return the resulting JSON with compact UTF-8 serialization. Responses are limited to 256 KiB of actual JSON bytes and message content to 32,000 characters. Call await app.close() during shutdown: it stops admission, waits up to 30 seconds for accepted handlers, then cancels and awaits remaining work. The built-in server and FastAPI adapter do this automatically.

Migrating from 0.3

Before:

@app.on("channel.message.created")
async def hello(event, client):
    await client.create_message(
        event.channel["id"], AppChannelMessage(content="Hello!")
    )

After:

@app.on("channel.message.created")
async def hello(event):
    await event.send("Hello!")

For explicit destinations use event.client.create_message(channel_id, content="..."). Change updates to event.client.update_message(message_id, content="...", etag=etag). Handlers no longer receive a second argument. Ordinary handlers run after acknowledgement and must return None; interactions can return strings for private replies.

Development

uv sync --extra fastapi
uv run ruff check .
uv run ruff format --check .
uv run pytest
uv build
uv run twine check dist/*