MODELS / ANTHROPIC

Claude Sonnet 5.5

Claude Sonnet 5.5 is a step-change improvement over Sonnet 5 for well-scoped everyday work like building features, fixing bugs, and creating polished documents, slides, and spreadsheets. It also writes more clearly than Sonnet 5.

TEXTREASONINGEXPLICIT-CACHINGFILE-INPUTREASONINGTOOL-USEVISIONWEB-SEARCHSTRUCTURED-OUTPUT
1M
CONTEXT WINDOW
128K
MAX OUTPUT TOKENS
$2
INPUT PRICE / 1M TOKENS
$10
OUTPUT PRICE / 1M TOKENS
QUICKSTART

Call it in one request.

OpenAI-compatible: change the base URL, and the setup is complete.

curl https://enterprise.blackbox.ai/v1/chat/completions \
  -H "Authorization: Bearer $BLACKBOX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "blackboxai/anthropic/claude-sonnet-5.5",
    "messages": [{ "role": "user", "content": "Hello!" }],
    "stream": true
  }'
SPECIFICATIONS

The full spec sheet.

Context, pricing, modalities, routing, and deployment: everything Claude Sonnet 5.5 supports, in one table.

MODEL ID
blackboxai/anthropic/claude-sonnet-5.5
DEVELOPED BY
Anthropic
MODEL TYPE
Text
RELEASED
Sep 28, 2026
CONTEXT WINDOW
1M
MAX OUTPUT TOKENS
128K
INPUT MODALITIES
text, image, pdf
OUTPUT MODALITIES
text
INPUT PRICE
$2 / 1M tokens
OUTPUT PRICE
$10 / 1M tokens
CACHE READ
$0.2 / 1M tokens
CACHE WRITE
$2.50 / 1M tokens
REASONING
Supported
DATA RETENTION
Standard retention
DEDICATED DEPLOYMENT
Not available (closed-weight model)
SUPPORTED PARAMETERS
max_tokensstoptoolstool_choicereasoninginclude_reasoningresponse_formatstructured_outputs