We build the runtime, evaluation and gateway layer that lets teams put large language models into production without rebuilding their stack — routing, guardrails, evals and cost control in one place.
Three pieces. Each one solves a problem that shows up the moment you move past a prototype.
Multi-provider model orchestration with deterministic fallbacks. Failover, retries and prompt versioning handled below your application code.
runtime.route(model, policy)
Continuous evaluation on your own traffic. Regression gates in CI, drift alerts, and per-release scorecards instead of vibes.
eval.gate(release, threshold)
One endpoint, one bill, per-team budgets. Unified auth, rate limits, PII redaction and audit logs across every provider you use.
gateway.enforce(tenant)
Teams usually land here after their second model migration. We shorten that path.
// routing + guardrails, one file import { nexus } from "@nexus/runtime"; export default nexus({ routes: [{ when: { task: "support-reply" }, prefer: "fast", maxCostPer1k: 0.9, fallback: ["gpt-class", "claude-class"] }], guard: { redact: ["pii", "secrets"], blockOnEvalDrop: 0.04 }, telemetry: { tenant: true, audit: true } });
Nexus AI Labs is a two-person founding team based in Los Angeles. We spent years shipping ML systems inside companies where a failed model migration meant a failed quarter. The tooling we wanted didn't exist, so we built the boring, reliable version of it — routing, evals, and governance that hold up under real traffic.
Founder & CEO · MS Computer Science, Stanford
Previously ML infrastructure. Building Nexus since 2021.
We take on a small number of design partners each quarter. Tell us what you're building and where it's breaking.