# Composer 2 Fast vs GPT-5.3 Codex

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

- Canonical page: https://benchlm.ai/compare/composer-2-fast-vs-gpt-5-3-codex
- Last updated: September 10, 2026

- Shared sourced benchmarks: 0
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

No benchmark verdict yet: there is no shared sourced benchmark row for Composer 2 Fast and GPT-5.3 Codex.

## Summary

- Composer 2 Fast and GPT-5.3 Codex do not currently share a sourced benchmark row. The mirror therefore compares metadata, pricing, context windows, and each model's separately reported coverage without naming a benchmark winner.

## Model Snapshot

| Property | Composer 2 Fast | GPT-5.3 Codex |
|----------|----------|----------|
| Creator | Cursor | OpenAI |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 200K | 400K |
| Independent public score (not head-to-head) | null | 64.29 |
| Benchmarks Covered | 1 | 8 |
| Pricing (input/output) | N/A | $1.75 / $14.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Composer 2 Fast public-lane score: Coming soon
- GPT-5.3 Codex public-lane score: 61.6 (Estimated · #15/152)

| Benchmark | Composer 2 Fast | GPT-5.3 Codex | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | Coming soon | 77.3% | Coming soon |
| 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 Fast public-lane score: Coming soon
- GPT-5.3 Codex public-lane score: 62 (Estimated · #17/151)

| Benchmark | Composer 2 Fast | GPT-5.3 Codex | Winner |
|-----------|-----------|-----------|--------|
| React Native Evals | 94.9% | Coming soon | Coming soon |
| SWE-bench Verified | Coming soon | 85% | Coming soon |
| SWE-bench Pro | Coming soon | 56.8% | Coming soon |
| SWE-Rebench | Coming soon | 58.2% | Coming soon |
| Vibe Code Bench | Coming soon | 61.77% | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Composer 2 Fast public-lane score: Coming soon
- GPT-5.3 Codex public-lane score: 75.6 (Unranked · 1 rankable row)

### Reasoning

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

### Knowledge

- Winner: Insufficient shared evidence
- Composer 2 Fast public-lane score: Coming soon
- GPT-5.3 Codex public-lane score: 65.6 (Estimated · #23/183)

### Instruction Following

- Winner: Insufficient shared evidence
- Composer 2 Fast public-lane score: Coming soon
- GPT-5.3 Codex public-lane score: 92.6 (#15/123)

## FAQ

### Can I compare Composer 2 Fast and GPT-5.3 Codex on BenchLM yet?

Not fully yet. BenchLM is tracking both models, but sourced benchmark coverage is still incomplete for a fair score-level comparison.

### Why does this page show "coming soon" values?

BenchLM only calls winners when public benchmark coverage is available on both sides of the comparison.

## Related Comparisons

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

## Explore More

- [Composer 2 Fast profile](/models/composer-2-fast)
- [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)