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GPT-5.4 Mini is available through Anyfast via the OpenAI Responses API (/v1/responses). It brings GPT-5.4 capabilities to a faster, lower-cost model for high-volume workloads.

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Key capabilities

  • Responses API — Uses the newer /v1/responses endpoint with input instead of messages
  • Reasoning control — Configure reasoning effort: none (default), low, medium, high, or xhigh
  • Coding and agents — Optimized for coding, computer use, and subagent workloads
  • Long context — Supports a 400K token context window and up to 128K output tokens
  • Multimodal input — Accepts text and image input, with text output
  • Tool use — Supports function calling and Responses API tools such as web search, file search, code interpreter, and computer use
  • Streaming — Supports real-time token streaming via SSE

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Quick example

curl https://www.anyfast.ai/v1/responses \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-5.4-mini",
    "input": [
      { "role": "user", "content": "Explain quantum entanglement in simple terms." }
    ],
    "reasoning": {
      "effort": "medium",
      "summary": "auto"
    },
    "text": {
      "format": { "type": "text" },
      "verbosity": "medium"
    },
    "store": true
  }'

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Parameters

ParameterTypeRequiredDescription
modelstringYesMust be gpt-5.4-mini
inputarrayYesList of { role, content } objects
streambooleanNoEnable SSE streaming. Default: false
top_pfloatNoNucleus sampling threshold. Default: 1
max_output_tokensintegerNoMaximum output tokens to generate
reasoningobjectNo{ effort, summary } — controls reasoning depth. effort supports none, low, medium, high, and xhigh
textobjectNo{ format, verbosity } — controls output format and verbosity
toolsarrayNoList of tools the model may call
storebooleanNoStore response for later retrieval. Default: true

API Reference

View the interactive API playground for GPT-5.4 Mini.