ZeroDOM

Point it at an app as two users. It finds the broken access control.

ZeroDOM drives your real, logged-in browser as two identities, replays the same requests as each, and flags where one user reaches what another can't — IDOR / broken access control, caught deterministically. Open-core, runs local, no account, no API key, nothing leaves your machine.

Under the hunt is a deterministic, token-lean perception engine for AI agents — the same core powers scan, crawl and any browser-driving task. IDOR is just where it bites hardest.

Quickstart

See it run in 10 seconds — no account, no browser download (bare zerodom <url> is a static fetch):

pip install zerodom
zerodom https://news.ycombinator.com     # the interaction graph + a token report

Find an IDOR. Save two logged-in sessions as Playwright storage_state files (one per account), then diff a protected endpoint across both:

zerodom compare https://app.example.com/api/admin/dashboard \
  --as user=user.json --as admin=admin.json

{
  "identities": { "user": { "status": 401 }, "admin": { "status": 200 } },
  "only_admin": ["Manage users", "Billing & plans", "Overview"],
  "note": "admin authorized (200) where user denied (401) — broken access control if the only difference is client-controllable"
}

Same request, two identities, a 401-vs-200 split → a lead to confirm. No LLM guessing: ZeroDOM surfaces the tell with the exact replay that proves it. You confirm the bug.

How it hunts

• zerodom compare — one endpoint across identities: a 401-vs-200 split, or a byte-identical cross-tenant response, is the IDOR tell.
• zerodom sweep URL --as user=… --as admin=… — the whole app in one command: crawls as one identity to map the GET surface, replays every in-scope URL across all identities, reports only the deterministic tells (--format md for a report table).
• zerodom crawl / scan / audit — recon: routes/forms/API plus the callable API surface (method + body) and DOM-XSS sinks read from the page's JS, response-header posture (CSP/CORS/cookie) and a csrf-posture correlation, and resolving the selectors in an existing test suite.
• zerodom repeat / probe / race — act & verify: a Repeater (--save HAR/.http evidence), a tampered-body diff for mass assignment (probe --tamper), and a concurrent burst to flag a check-then-act race (race; HTTP/2 multiplexing via the zerodom[race] extra).

It drives your real Chrome (relay mode) over chrome.debugger — cookies, MFA, SSO already done — or a throwaway browser (--stealth). Read-only by default; scope is enforceable and lockable. Route through Burp/Caido with --proxy. Only test targets you're authorized to.

From an AI agent (MCP)

ZeroDOM is a native MCP server. Claude, Cursor, LangGraph, CrewAI, the OpenAI Agents SDK, Pydantic AI and more load the full 39-tool set from one config:

{ "mcpServers": { "zerodom": { "command": "uvx", "args": ["--from", "zerodom", "zerodom-mcp"] } } }

Run zerodom setup for a guided first-run. Runnable per-framework examples: examples/integrations/.

Why the agent sees so few tokens

A live page becomes a flat list where every entry has an id that resolves to exactly one element, and the CSS selector never enters the model's context:

[01] a 'Show HN: ZeroDOM — agents only need to know what they can click'
[02] a 'dev'
[03] a '214 comments'

Deterministic (lxml in, graph out, no LLM). Measured and re-runnable: ~71% fewer tokens than Playwright MCP's aria_snapshot(mode="ai") (mean; ~53–96% per site), 99.00% of 10,756 audited selectors across 111 live sites resolve to exactly one element, parse median 55ms.

Open core

Everything in the package — parser, CLI, relay, stealth, scan/crawl/compare/audit, the clearance ladder, the MCP server — is the free, Apache-2.0 Core, complete on its own: one operator, local, no account, no key. Enterprise is an additive team layer (fleet dashboard, compliance export packs, SSO/RBAC, SLA) that never gates, phones home from, or adds telemetry to the Core. Details: contact@vexralabs.com.

GitHub · Docs · Site · Discord — Apache-2.0, a Vexra Labs project.