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OpenAI Responses

gpt-5.3-chat

GPT-5.3 Chat is an update to ChatGPT's most-used model that makes everyday conversations smoother, more useful, and more directly helpful. It delivers more accurate answers with better contextualization and significantly reduces unnecessary refusals, caveats, and overly cautious phrasing that can interrupt conversational flow.

👁Vision🧠Reasoning🔧Tool calling⚡Caching
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Specifications

Context window128K tokens
Max output16K tokens
API typechat
AddedMar 18, 2026
Model IDopenai-responses/gpt-5.3-chat
Data retentionYes (30 days)
Used for trainingNo
Provider location🇺🇸 US
Privacy policyOpenAI Privacy Policy→

Benchmarks

Benchmarks haven't been published yet for this exact variant.

Some variants (region-specific deployments, highspeed tiers) share benchmarks with their base model — check the base model page or the OpenAI Responses models overview.

Pricing

Input / 1M
$1.75
Output / 1M
$14.00
Cache write / 1M
$14.00
Cache read / 1M
$0.17
Estimated cost
100K input + 10K output$0.31
1M input + 100K output$3.15
10M input + 1M output$31.50

Requesty charges exactly what the upstream provider charges — no markup, no per-request fees. Prompt caching and smart routing can reduce effective cost by 30-80%.

Quickstart

Drop-in compatible with the OpenAI SDK. Change the base URL, swap in your Requesty API key, and set the model to openai-responses/gpt-5.3-chat.

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from openai import OpenAI

client = OpenAI(
    api_key="YOUR_REQUESTY_API_KEY",
    base_url="https://router.requesty.ai/v1",
)

response = client.chat.completions.create(
    model="openai-responses/gpt-5.3-chat",
    messages=[
        {"role": "user", "content": "Explain quantum computing in one paragraph."},
    ],
)

print(response.choices[0].message.content)

Other OpenAI Responses models

gpt-5.5
1.1M ctx$5.00/1M
gpt-5.5-pro
1.1M ctx$30.00/1M
gpt-5.4-mini
400K ctx$0.75/1M
gpt-5.4-nano
400K ctx$0.20/1M
gpt-5.4
1.1M ctx$2.50/1M
SWE-Bench 82%
gpt-5.3-codex
400K ctx$1.75/1M

Frequently asked questions

How much does gpt-5.3-chat cost?
gpt-5.3-chat is priced at $1.75 per million input tokens and $14.00 per million output tokens when accessed via Requesty. Prompt caching is supported, which can cut effective input cost by up to 90% on repeated context. Requesty charges exactly what the upstream provider charges — we don't add markup.
What is the context window of gpt-5.3-chat?
gpt-5.3-chat has a context window of 128K tokens, with a maximum output of 16K tokens per response. That's roughly 171 words of input you can fit in a single prompt.
What can gpt-5.3-chat do?
gpt-5.3-chat supports vision input, tool calling, extended reasoning, prompt caching. You can call it through any OpenAI-compatible client by pointing base_url to Requesty.
How do I use gpt-5.3-chat with the OpenAI SDK?
Install the OpenAI SDK, set base_url to "https://router.requesty.ai/v1", set your API key to your Requesty key, and set the model to "openai-responses/gpt-5.3-chat". The Quickstart above shows Python, JavaScript and cURL snippets.

Access gpt-5.3-chat through Requesty

One API key, 400+ models, OpenAI-compatible. No markup on provider prices, automatic failover, and smart caching built-in.

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