gpt-5.5 vs gpt-5.3-codex
Side-by-side comparison of gpt-5.5 and gpt-5.3-codex: benchmarks, pricing, context window and capabilities. Both are accessible through Requesty's unified API. gpt-5.5 outperforms gpt-5.3-codex on 5 of 5 shared benchmarks.
gpt-5.5
Input / 1M
$5.00
Output / 1M
$30.00
Context
1.1M
Model ID
openai/gpt-5.5
gpt-5.3-codex
Input / 1M
$1.75
Output / 1M
$14.00
Context
400K
Model ID
openai-responses/gpt-5.3-codex
Benchmark comparison
Intelligence Indexreasoning
gpt-5.545.6%
gpt-5.3-codex36.9%
Coding Indexcoding
gpt-5.574.9%
gpt-5.3-codexN/A
GPQA Diamondreasoning
gpt-5.593.5%
gpt-5.3-codex91.5%
Terminal-Bench Hardagentic
gpt-5.560.6%
gpt-5.3-codex53.0%
τ²-Benchagentic
gpt-5.593.9%
gpt-5.3-codex86.0%
Humanity's Last Examreasoning
gpt-5.545.8%
gpt-5.3-codex42.5%
Scores sourced from official model cards, Artificial Analysis, and public leaderboards. Benchmarks measure specific skills and don't capture every aspect of model quality.
Pricing & specifications
| gpt-5.5 | gpt-5.3-codex | |
|---|---|---|
| Input price / 1M | $5.00 | $1.75 |
| Output price / 1M | $30.00 | $14.00 |
| Context window | 1.1M tokens | 400K tokens |
| Max output | 128K tokens | 128K tokens |
| Vision input | Yes | Yes |
| Tool calling | Yes | Yes |
| Reasoning | Yes | Yes |
| Prompt caching | Yes | Yes |
| Computer use | N/A | N/A |
| Provider | OpenAI Inc. | OpenAI Responses |
Questions people ask
Is gpt-5.5 better than gpt-5.3-codex?
gpt-5.5 outperforms gpt-5.3-codex on 5 of 5 shared benchmarks. See the benchmark comparison above for specifics: gpt-5.5 and gpt-5.3-codex have different strengths across reasoning, coding, math and multimodal tasks.
Which is cheaper, gpt-5.5 or gpt-5.3-codex?
gpt-5.3-codex is cheaper. gpt-5.5 costs $5.00/$30.00 per 1M input/output tokens, while gpt-5.3-codex costs $1.75/$14.00.
Can I use gpt-5.5 and gpt-5.3-codex through the same API?
Yes. Requesty provides a single OpenAI-compatible API that routes to both. Change just the "model" parameter to switch between "openai/gpt-5.5" and "openai-responses/gpt-5.3-codex", no other code changes needed.
What are the context windows?
gpt-5.5 supports up to 1.1M tokens of context. gpt-5.3-codex supports up to 400K tokens. Longer context means you can feed larger documents or codebases in a single prompt, though quality often degrades past 128K for most models.
Switch between gpt-5.5 and gpt-5.3-codex with one line of code
Requesty provides a single OpenAI-compatible API for 600+ models. Change the model parameter, not your code.