TEXTREASONINGFILE-INPUTIMPLICIT-CACHINGREASONINGTOOL-USEVISIONWEB-SEARCHWEBSOCKET-REALTIMEFAST
400K
CONTEXT WINDOW
128K
MAX OUTPUT TOKENS
$3.50
INPUT PRICE / 1M TOKENS
$28
OUTPUT PRICE / 1M TOKENS
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-5.3-codex-fast",
"messages": [{ "role": "user", "content": "Hello!" }],
"stream": true
}'import os
from openai import OpenAI
client = OpenAI(
api_key=os.environ.get("BLACKBOX_API_KEY"),
base_url="https://enterprise.blackbox.ai/v1",
)
stream = client.chat.completions.create(
model="blackboxai/openai/gpt-5.3-codex-fast",
messages=[{"role": "user", "content": "Hello!"}],
stream=True,
)
for chunk in stream:
print(chunk.choices[0].delta.content or "", end="", flush=True)import OpenAI from 'openai';
const client = new OpenAI({
apiKey: process.env.BLACKBOX_API_KEY,
baseURL: 'https://enterprise.blackbox.ai/v1',
});
const stream = await client.chat.completions.create({
model: 'blackboxai/openai/gpt-5.3-codex-fast',
messages: [{ role: 'user', content: 'Hello!' }],
stream: true,
});
for await (const chunk of stream) {
process.stdout.write(chunk.choices[0]?.delta?.content || '');
}The full spec sheet.
Context, pricing, modalities, routing, and deployment: everything GPT 5.3 Codex (Fast) supports, in one table.
- MODEL ID
- blackboxai/openai/gpt-5.3-codex-fast
- DEVELOPED BY
- OpenAI
- MODEL TYPE
- Text
- RELEASED
- Feb 5, 2026
- CONTEXT WINDOW
- 400K
- MAX OUTPUT TOKENS
- 128K
- INPUT MODALITIES
- text, image, pdf
- OUTPUT MODALITIES
- text
- INPUT PRICE
- $3.50 / 1M tokens
- OUTPUT PRICE
- $28 / 1M tokens
- CACHE READ
- $0.35 / 1M tokens
- REASONING
- Supported
- DATA RETENTION
- Standard retention
- DEDICATED DEPLOYMENT
- Not available (closed-weight model)
- SUPPORTED PARAMETERS
- max_tokenstemperaturestoptoolstool_choicereasoninginclude_reasoning