Sylphx

Lumen gets better every day

One engine, four tiers, the same model ids forever. Watch it work below — then see the daily measurements that prove the trend.

Animated sample session: a request streams back a complete Lumen answer in real time.

4
tiers, evaluated daily
Index calibrating
Position-swapped
judging, every duel

The trend is measured, not asserted.

A five-part quality score, refreshed by scheduled runs, published for every tracked model — not a number we picked once and kept repeating.

No version numbers to chase

New lanes are admitted, rated, and promoted as the market moves. Every improvement lands behind the exact model id you already integrated — automatically, continuously, forever.

400,000 tokens

The advertised context window today — a floor enforced in code. It only rises from here. Never regressed, never just a marketing figure.

Every claim is checked in production

Quality isn't asserted once. It's re-verified continuously, on real traffic, before anything ships.

Shadow duels

A sibling lane invisibly answers the same request, off your path. A family-disjoint judge compares both — position-swapped both ways, so order never decides the winner.

Zero retention

Only the anonymous win/loss score survives a duel. Never the prompt, the output, or who sent it.

Promotion gates

A lane earns a serving seat only after enough judged duels at or above the pool's median — shipped as a reviewed config change, rolled back automatically if live quality slips.

One engine. Four ways to spend on it.

Every tier runs the same router, the same lanes, the same certification. Tier separation — Flash ≤ Standard ≤ Pro ≤ Ultra — is checked continuously against production duels, never asserted once.

Lumen Flash

Cheapest lane that clears the bar. Maximum thrift.

sylphx/lumen-flash
Choose it whenLatency-sensitive UI or bulk light tasks
Default

Lumen

The default. Best value in the family.

sylphx/lumen
Choose it whenNot sure which tier you need

Lumen Pro

The predicted best. You pay for the ceiling.

sylphx/lumen-pro
Choose it whenYour agent plans, architects, or reasons hard

Lumen Ultra

Council on demand

Zero tolerance — plus a council when it's hard.

sylphx/lumen-ultra
Choose it whenThe answer is worth waiting for when it's hard

Ready to build?

Get your API key in under a minute. No credit card required to start.

quick start
import OpenAI from "openai"

const client = new OpenAI({
  apiKey: "sk-sx-...",
  baseURL: "https://api.sylphx.ai/v1",
})

const response = await client.chat.completions.create({
  model: "sylphx/lumen",
  messages: [{ role: "user", content: "Hello!" }],
})

console.log(response.choices[0].message.content)