An open-source secure AI browser engine built for the agentic era.
Describe it. Sepia finds it, acts on it, scales it — privately.
80
Median tokens
per page view
231
Tests passing
in CI
18
MCP tools
available
Every existing tool sends the model too much noise, breaks on redesigns, and is trivially detected by modern anti-bot systems. Enterprises deploying AI agents face three compounding failures.
Raw HTML dumps average 8,700+ tokens of noise per page. Screenshots are opaque. DOM trees carry structure without meaning. Every model call burns budget on content the model can't use.
CSS selectors break the moment a class is renamed. XPath breaks when a wrapper <div> is added. One redesign cycle takes down entire automation pipelines — maintenance costs compound faster than value delivered.
Header-level User-Agent spoofing is a decade-old technique. Modern anti-bot systems fingerprint TLS ClientHello, HTTP/2 frame ordering, Canvas, and WebGL — cross-correlating signals in milliseconds. A Chrome UA with Firefox TLS is detectable instantly.
The Business Impact
Every failed automation run costs engineering time to diagnose, customer experience to lose, and AI budget to waste. At enterprise scale, these failures compound into millions in hidden operational cost.
Sepia addresses token cost, layout fragility, and detection resistance in one unified engine — designed from the ground up for the agentic era.
Sepia distills each page to a compact semantic outline from the accessibility tree. One line per meaningful element. The model reasons about handles like [e12] button "Sign in" — never raw selectors.
Handles derive from meaning, not structure: role + accessible name + ordinal. When a site ships a redesign that moves your button to a different container, the handle is unchanged. When the element is gone, Sepia marks it stale and stops.
The configured fingerprint preset — UA, locale, timezone, viewport — is applied at context creation and validated before the session starts. navigator.webdriver is masked. If signals contradict each other, the session refuses to start.
From a single plain-language goal to scaled workflows across thousands of pages — Sepia handles the full spectrum of enterprise browser automation.
Automate login, session management, and multi-step authenticated flows. Credentials never enter the model context — privacy module redacts secrets before every observation.
Navigate search results, extract structured data, and aggregate information across pages. Returns typed RunTrace JSON — ready for downstream pipelines.
Fill complex multi-step forms — dropdowns, checkboxes, file uploads — with typed action validation. Model output is never eval'd; only a typed action enum is dispatched.
Chain actions across multiple pages in a single goal — add to cart, navigate to checkout, apply coupon, confirm. The agent loop maintains state across page transitions.
Run the same goal across N inputs in parallel. HTTP server mode supports up to configurable concurrent sessions with bearer-token-protected API. Kubernetes Helm chart included for enterprise scale.
Monitor pricing pages, track feature launches, and aggregate competitor data into structured reports. Ephemeral browser profiles ensure clean-session isolation between runs.
A deterministic core with side effects only at the edge. The serializer and resolver are pure functions — no LLM calls, fully unit-tested, identical in production and CI.
Plan
Parse plain-language goal into task
Observe
Build compact view from AX tree
Act
Validate & dispatch typed action
Verify
Check confidence, retry or stop
One-shot agent runs from the terminal. Returns structured RunTrace JSON with full step audit trail.
REST API for enterprise integrations. Bearer-token auth required. Configurable concurrency. Kubernetes Helm chart for scale.
18 tools for Claude Code, Claude Desktop, and Codex. No model key required — the host agent reasons; Sepia drives the browser.
file://, data://, javascript: schemes
Configure any model provider via environment variables. Local inference with Ollama needs no API key.
Anthropic
Claude Sonnet / Opus
OpenAI
GPT-4o / o3
OpenRouter
400+ models
Ollama
Local · no API key
Deep-dive into Sepia's architecture, security model, token economics, enterprise deployment patterns, and ROI analysis. Designed for CTOs, architects, and security teams evaluating AI browser infrastructure.