Model card

Claude Sonnet 5

lx1-sonnet-5PremiumLive in the catalog

A generation past Sonnet 4.6 and the balance point of the premium tier: much of Opus's judgment at a fraction of the cost, with vision and a 200K window. For premium work you do all day — reviews, hard edits, anything that needs eyes on an image — this is the one that earns its place in the loop.

Context window200K tokens

Input · per Mtok$3

Output · per Mtok$15

Served byLayer X1 engine

Where it earns its keep[01/03]

01Near-frontier reasoning at a workable price
02Vision plus a 200K context window
03A strong, steady premium default

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.

Claude Sonnet 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-sonnet-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.