MODELS / OPENAI

GPT 5.5 (Fast)

GPT‑5.5 understands what you’re trying to do faster and can carry more of the work itself. It excels at writing and debugging code, researching online, analyzing data, creating documents and spreadsheets, operating software, and moving across tools until a task is finished.…

TEXTREASONINGFILE-INPUTIMPLICIT-CACHINGREASONINGTOOL-USEVISIONWEB-SEARCHWEBSOCKET-REALTIMEFAST
1M
CONTEXT WINDOW
128K
MAX OUTPUT TOKENS
$12.50
INPUT PRICE / 1M TOKENS
$75
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/openai/gpt-5.5-fast",
    "messages": [{ "role": "user", "content": "Hello!" }],
    "stream": true
  }'
SPECIFICATIONS

The full spec sheet.

Context, pricing, modalities, routing, and deployment: everything GPT 5.5 (Fast) supports, in one table.

MODEL ID
blackboxai/openai/gpt-5.5-fast
DEVELOPED BY
OpenAI
MODEL TYPE
Text
RELEASED
Apr 24, 2026
CONTEXT WINDOW
1M
MAX OUTPUT TOKENS
128K
INPUT MODALITIES
text, image, pdf
OUTPUT MODALITIES
text
INPUT PRICE
$12.50 / 1M tokens
OUTPUT PRICE
$75 / 1M tokens
CACHE READ
$1.25 / 1M tokens
REASONING
Supported
DATA RETENTION
Standard retention
DEDICATED DEPLOYMENT
Not available (closed-weight model)
SUPPORTED PARAMETERS
max_tokenstemperaturestoptoolstool_choicereasoninginclude_reasoning