The runtime for code no human wrote.

Agents generate and execute code constantly. rayJS runs it with near-zero startup, a footprint measured in kilobytes, deterministic results, and zero access to anything by default.

Request a rayJS demo See the numbers ↓

002

002 / INTERNAL MEASUREMENTS

Near-zero is the new baseline.

Agent systems execute code constantly. rayJS removes the cold-start and memory tax that turns every small decision into infrastructure.

STARTUP / SMALL SCRIPT

<1^ms

From launch to execution in less time than most systems take to notice a request.

RUNTIME OVERHEAD

100^s KB

A radically smaller footprint than general-purpose JavaScript infrastructure.

DENSITY / STABLE INSTANCE

10K^s runs

Tens of thousands of isolated executions launched in seconds.

EXECUTION TIME / LOWER IS BETTER

Closing in on V8.

rayJS now runs our internal suite within roughly 1.7× of V8 — while keeping the startup, footprint, determinism, and isolation agent platforms need.

V8 REFERENCE

1.0×

RAYJS CURRENT

1.7×

Figures shown are directional internal measurements. Workload, environment, and warmup affect results.

003

003 / LOCKED DOWN BY DEFAULT

Nothing gets in. Until you let it.

Every execution starts with zero access. Add only the capabilities the workload needs — an input, an approved API, a specific operation — and nothing else.

CAPABILITY LEDGER / DEFAULT POLICY

fs.readFile("/etc/passwd")DENIED
net.connect("0.0.0.0:443")DENIED
process.envDENIED
child_process.spawn("sh")DENIED
fetch("api.approved.example")GRANTED

Zero ambient authority

No filesystem, network, database, or system access unless you provide it.

Exact capability control

Expose the smallest useful surface for each task and each agent — an input, an approved API, a specific operation.

Deterministic execution

The same contained inputs produce the same reproducible result, every time.

004

004 / THE EXECUTION LANDSCAPE

Built for a different job.

Browsers optimize pages. Mobile engines optimize apps. Containers and microVMs isolate machines. rayJS is designed around the execution pattern agent platforms actually have.

ENGINEBUILT FORSTARTUPLOCKED DOWN BY DEFAULT

V8Browsers and long-lived servers. Peak throughput reference.warm processes—

JavaScriptCoreWebKit. Multi-tier engine built for browser and app workloads.warm processes—

HermesMobile apps. Compact bytecode and fast on-device startup.fast, on-device—

QuickJSEmbeddability. A small engine with broad modern support.milliseconds—

V8 isolatesEdge platforms. Lightweight per-function contexts.milliseconds—

FirecrackerMicroVM isolation with documented startup around 125 ms.~125 ms—

rayJSAgent execution: thousands of small, untrusted, disposable programs.<1 ms● zero access

Landscape descriptions reflect each project's public positioning. rayJS figures are directional internal measurements.

005 / SELECT CUSTOMER ACCESS

Bring us the code you would never let an agent run.

rayJS already supports customer workloads in production. We work directly with agent-platform teams to design safe, high-density execution around their real systems.

Request a rayJS demo →

TOOL EXECUTIONDETERMINISTIC REPLAY10K RUNTIME LAUNCH