Question 1

What is GPT-5.4?

Accepted Answer

GPT-5.4 is a model from OpenAI, released on Mar 5, 2026. GPT-5.4 is OpenAI’s latest frontier model, unifying the Codex and GPT lines into a single system. It features a 1M+ token context window (922K input, 128K output) with support for text and image inputs, enabling high-context reasoning, coding, and multimodal analysis within the same workflow. The model delivers improved performance in coding, document understanding, tool use, and instruction following. It is designed as a strong default for both general-purpose tasks and software engineering, capable of generating production-quality code, synthesizing information across multiple sources, and executing complex multi-step workflows with fewer iterations and greater token efficiency.

Question 2

How much does GPT-5.4 cost?

Accepted Answer

On the Respan gateway, input starts at $1.25 per 1M tokens on Azure OpenAI, and output starts at $10.00 per 1M tokens on Azure OpenAI, after gateway discounts. Averaged across 7 providers, it costs $2.32 per 1M input tokens and $14.29 per 1M output tokens.

Question 3

Which providers serve GPT-5.4 on Respan?

Accepted Answer

7 providers serve GPT-5.4: Azure OpenAI, Inference.net, OpenAI, OpenRouter, and Perplexity. Azure OpenAI and Perplexity require your own provider API key (BYOK).

Question 4

What is GPT-5.4's context window?

Accepted Answer

GPT-5.4 accepts up to 1.1M tokens of context on its largest provider route.

Question 5

How do I use GPT-5.4 with the Respan gateway?

Accepted Answer

Point any OpenAI-compatible SDK at https://api.respan.ai/api/ with your Respan API key and set the model to "openai/gpt-5.4". To set it up with a coding agent, copy the agent setup prompt at the top of this page.

Question 6

How fast is GPT-5.4?

Accepted Answer

Over the last 30 days of requests through the Respan gateway, the fastest provider was OpenAI at 16 tokens per second, and the lowest response latency was 0.6 seconds on OpenAI. Speed varies with request size and provider.

Question 7

Where does GPT-5.4 rank on the Respan Index?

Accepted Answer

GPT-5.4 scores 47.2 out of 100 on the Respan Index v1.1, ranking #28 of 138 models. By category: Coding 25.9, Agents 61.1, Reasoning 52.9, Knowledge & language 46.7, and Human preference 50.3. The Respan Index combines independent and lab-reported benchmark results into one score, using benchmark data collected by llmmetric.com.

Question 8

How does GPT-5.4 score on benchmarks?

Accepted Answer

GPT-5.4 has 46 published benchmark scores, including WeirdML 77.7%, Tau2-bench Telecom 98.9%, and GPQA Diamond 93.3%. Each score links to where it was published; the data is collected by llmmetric.com.

Provider	Context	Input	Output
Azure OpenAIBYOK only`azure_openai/gpt-5.4`	272K	$1.25/M	$10.00/M
Azure OpenAIBYOK only`azure/gpt-5.4`	1.1M	$2.50/M	$15.00/M
Inference.net`inference_net/gpt-5.4`	1.1M	$2.50/M	$15.00/M
OpenAI`openai/gpt-5.4`	1.1M	$2.50/M	$15.00/M
OpenAI`openai/gpt-5.4-2026-03-05`	1.1M	$2.50/M	$15.00/M
OpenRouter`openrouter/openai/gpt-5.4`	1.1M	$2.50/M	$15.00/M
PerplexityBYOK only`perplexity/openai/gpt-5.4`	1.1M	$2.50/M	$15.00/M

GPT-5.4

Providers

Certified where it counts.

Pricing

Cost by volume

Throughput and latency

Output speed

Response latency

Benchmarks

Respan Indexv1.1

Coding8

Apps

GPT-5.4 FAQ

Works with your entire stack

Built for AI agents.
Break less.
Ship more.

Agents10

Reasoning9

Math7

Knowledge4

Multimodal3

Arena4

Other1