# Composer 2 vs GPT-5.3 Codex

> Side-by-side benchmark comparison for Composer 2 and GPT-5.3 Codex across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/composer-2-vs-gpt-5-3-codex
- Last updated: September 21, 2026

- Shared sourced benchmarks: 2
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

Evidence is too thin for a benchmark verdict: Composer 2 and GPT-5.3 Codex share only 2 sourced benchmark rows.

## Summary

- Only 2 shared sourced benchmark rows are available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- Composer 2 has the lower published output-token price.
- GPT-5.3 Codex has the larger published context window at 400K.

## Model Snapshot

| Property | Composer 2 | GPT-5.3 Codex |
|----------|----------|----------|
| Creator | Cursor | OpenAI |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 200K | 400K |
| Independent public score (not head-to-head) | null | 64.01 |
| Benchmarks Covered | 5 | 10 |
| Pricing (input/output) | $0.50 / $2.50 | $1.75 / $14.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Composer 2 public-lane score: 49.5 (Estimated · #64/154)
- GPT-5.3 Codex public-lane score: 61.7 (Estimated · #15/154)

| Benchmark | Composer 2 | GPT-5.3 Codex | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 61.7% | 77.3% | GPT-5.3 Codex |
| OSWorld-Verified | Coming soon | 64.7% | Coming soon |
| Gert Labs | Coming soon | 57.47% | Coming soon |
| JobBench | Coming soon | 33.7% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Composer 2 public-lane score: 49.5 (Estimated · #68/156)
- GPT-5.3 Codex public-lane score: 62.2 (Supported · #18/156)

| Benchmark | Composer 2 | GPT-5.3 Codex | Winner |
|-----------|-----------|-----------|--------|
| SWE Multilingual | 73.7% | Coming soon | Coming soon |
| SWE-Rebench | 58% | 58.2% | GPT-5.3 Codex |
| React Native Evals | 96.1% | Coming soon | Coming soon |
| Terminal-Bench 2.0 | 61.7% | Coming soon | Coming soon |
| SWE-bench Verified | Coming soon | 85% | Coming soon |
| SWE-bench Pro | Coming soon | 56.8% | Coming soon |
| Vibe Code Bench | Coming soon | 61.77% | Coming soon |
| LiveCodeBench (Vals) | Coming soon | 87.3% | Coming soon |
| SWE-bench (Vals) | Coming soon | 78.0% | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Composer 2 public-lane score: Coming soon
- GPT-5.3 Codex public-lane score: 78.3 (Unranked · 2 rankable rows)

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Composer 2 public-lane score: Coming soon
- GPT-5.3 Codex public-lane score: 75.7 (Unranked · 1 rankable row)

### Knowledge

- Winner: Insufficient shared evidence
- Composer 2 public-lane score: Coming soon
- GPT-5.3 Codex public-lane score: 65.7 (Estimated · #22/186)

### Instruction Following

- Winner: Insufficient shared evidence
- Composer 2 public-lane score: Coming soon
- GPT-5.3 Codex public-lane score: 91.2 (#14/124)

## FAQ

### Is there enough evidence to pick between Composer 2 and GPT-5.3 Codex?

Not yet. The models share only 2 sourced benchmark rows, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [Composer 2 vs Composer 2.5](/compare/composer-2-vs-composer-2-5)
- [GPT-5.3 Codex vs Composer 2.5](/compare/composer-2-5-vs-gpt-5-3-codex)
- [Composer 2 vs Composer 2 Fast](/compare/composer-2-vs-composer-2-fast)
- [GPT-5.3 Codex vs Composer 2 Fast](/compare/composer-2-fast-vs-gpt-5-3-codex)

## Explore More

- [Composer 2 profile](/models/composer-2)
- [GPT-5.3 Codex profile](/models/gpt-5-3-codex)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)