Passage Platform

Low-level session control with Playwright-style browser commands.

What is Platform?

Passage Platform gives you direct control over browser sessions. Your backend connects via WebSocket to a session actor, sends commands (navigate, click, type, evaluate), and yields to the user when human interaction is needed. The client SDK executes commands in a webview on the user’s device.

Architecture

The session actor is the core — a stateful process that relays commands between your backend (the “worker”) and the client SDK. Commands flow one at a time: your backend sends a command, the client executes it, and the result comes back. When the user needs to interact, you yield control and wait for conditions to be met.


┌─────────────┐         ┌────────────────┐         ┌─────────────────┐
│ Your Backend│         │ Session Actor  │         │   Client SDK    │
│  (worker)   │         │   (stateful)   │         │   (webview)     │
└──────┬──────┘         └───────┬────────┘         └────────┬────────┘
       │                        │                           │
       │  worker.command        │  server.command           │
       │───────────────────────►│──────────────────────────►│
       │                        │                           │
       │                        │  client.command_response  │
       │  server.command_result │◄──────────────────────────│
       │◄───────────────────────│                           │
       │                        │                           │
       │  worker.yield_to_user  │  server.set_interactive   │
       │───────────────────────►│──────────────────────────►│
       │                        │                           │
       │                        │    ┌──────────────────┐   │
       │                        │    │ User interacts   │   │
       │                        │    │ in webview       │   │
       │                        │    └──────────────────┘   │
       │                        │                           │
       │                        │  client.events (stream)   │
       │  server.command_result │◄──────────────────────────│
       │◄───────────────────────│  (condition matched)      │
       │                        │                           │

Key concepts

Sessions — The session lifecycle and state machine
Commands — Playwright-style browser commands (navigate, click, type, evaluate)
Yield to User — Hand control to the user and wait for conditions
Events — Telemetry events streamed from the client

Protocol

For full wire-level details on the WebSocket protocol:

Protocol Overview — Message format and connection model
WebSocket Connection — Connecting, authentication, and roles

Get started

Quickstart — Create a session and send your first command
Building a Worker — Write a complete automation backend