Model card

GPT-5.5

lx1-gpt-5.5FrontierLive in the catalog

A frontier generalist that stays composed across long agent runs: strong reasoning, reliable tool calling, and a very large context window. The model to reach for when the work is broad and unforgiving — research that has to be right, refactors that span the repo, plans that can't drift.

Context window400K tokens

Input · per Mtok$2.5

Output · per Mtok$15

Served byLayer X1 engine

Where it earns its keep[01/03]

01Frontier reasoning across broad, open-ended work
02Holds tool discipline over long chains
03400K context for repo-scale tasks

Capabilities

Tool callingYes

Strict, schema-faithful tool calls, enforced by the engine on every request — safe to build an agent loop on.

ReasoningYes

Thinks before it answers. Budget max_tokens generously — hidden reasoning counts against it.

VisionYes

Reads images — screenshots, diagrams, and UI states — inline in the conversation.

Behind the endpoint[02/03]

One endpoint. Served by our engine.

GPT-5.5 is served through the Layer X1 engine — zero-downtime serving is the design target, not a status-page apology. You request it by name; everything else is our problem.

Call it by name

curl https://api.layerx1.in/v1/messages \
  -H "x-api-key: lx1_your_key" \
  -H "content-type: application/json" \
  -d '{
    "model": "lx1-gpt-5.5",
    "max_tokens": 1024,
    "messages": [{ "role": "user", "content": "Hello" }]
  }'

OpenAI-style clients work too — send the same model name to /v1/chat/completions with a Bearer key. See the docs for both dialects.

Your agent doesn't change.
Everything underneath does.

$export ANTHROPIC_BASE_URL=https://api.layerx1.in

Get a key Read the docs

Start free · no card · Starter from $5/mo

One endpoint. Served by our engine.

Your agent doesn't change.Everything underneath does.

Your agent doesn't change.
Everything underneath does.