GPT-5.4 is OpenAI's established reasoning model — 1M context, 128K max output, and a drop-in /v1/chat/completions endpoint. The cost-efficient route in the GPT family for production traffic that doesn't need GPT-5.5's newest reasoning gains.
gpt-5.4Chat models run on the api.reapi.ai gateway, which has its own console and its own key. Open the console to run GPT-5.4 through the OpenAI-compatible Chat Completions surface.
Credit-based — 1 credit = $0.001 USD. Pay only for completed generations.
One 1K-token prompt with a 1K-token answer at the cheapest tier.
GPT-5.4 is OpenAI's established reasoning model, served on reAPI as a drop-in OpenAI-compatible /v1/chat/completions endpoint. It reads a 1M-token context window, returns up to 128K tokens in a single response, and covers function calling, JSON-mode output and low-latency streaming — the cost-efficient route in the GPT family for production traffic that does not need GPT-5.5's newest reasoning gains. Billing is per 1M tokens, with input and output priced separately.
Real-world workflows and production use cases you can build and ship with this model.
Run GPT-5.4 as the default model behind a chatbot, support assistant, or internal copilot. The cost-efficient pricing in the GPT family keeps per-request spend low while you still get reasoning, streaming, and tool use behind one endpoint.
Read the API docs
Feed entire policy documents, transcripts, contracts, or research sets into a single GPT-5.4 call. The 1M token context window means you rarely need to chunk — the model sees the whole document and returns a coherent summary, review, or comparison.
Pull structured JSON out of free-text inputs, classify tickets and reviews into a fixed taxonomy, or normalise messy fields against a schema. GPT-5.4 returns reliable JSON via `response_format` and standard OpenAI tool calling — no custom parser required.
The GPT-5.4 API speaks OpenAI Chat Completions verbatim. Moving an existing OpenAI integration is a base URL, an API key, and a model-string change — not a platform rewrite. Same `messages` array, same `stream` / `temperature` / `top_p` / `frequency_penalty` / `presence_penalty` parameters, same SSE wire format.
GPT-5.4 is the lowest-priced route in the GPT family — pay-as-you-go in USD, no monthly minimum. Pick it for established workloads where the volume is high and the marginal cost of each call matters more than squeezing the last few points of reasoning quality.
A single api.reapi.ai key unlocks GPT-5.4 alongside GPT-5.5, Claude Opus 4.7, Gemini 3.1 Pro, and every other frontier chat model on the platform. Compare vendors, add fallbacks, and route traffic per call with a configuration change instead of an integration project.
Sign up at api.reapi.ai, open the console, generate an API key under API Keys, and top up tokens under Top Up. The chat workspace is separate from the reapi.ai image/video gateway — keys do not cross over.
OpenPOST https://api.reapi.ai/v1/chat/completions with `model: "gpt-5.4"`, your `messages` array, and any optional parameters. The endpoint uses the standard chat-completions format, including streamed responses.
OpenOpen the GPT-5.4 docs for the full request schema, error envelope, and language-specific code samples (cURL, Python, Node.js, Go).
Opencurl https://api.reapi.ai/v1/chat/completions \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "gpt-5.4",
"group": "default",
"messages": [
{ "role": "user", "content": "Hello" }
],
"stream": true,
"temperature": 0.7,
"top_p": 1,
"frequency_penalty": 0,
"presence_penalty": 0
}'Rejected synchronously with the failing field named. Check enum values, ranges, and URL fields — nothing is charged.
401 means a missing or invalid Bearer key; 402 means the reserve exceeds your balance. Manage keys and credits in the console.
Reference material and outputs pass automated moderation. Rejected tasks fail with a clear error and a full refund.
A task that reaches a failed state is never charged — the reserve refunds automatically. Keep the task id and retry when ready.
Common questions about this model.
Try it in the playground or grab an API key to integrate now.
