Model comparison
GPT-5.3 Codex vs Longcat Flash Chat
GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 42.1 on the Noometry Index.
Last verified . 0 shared benchmarks.
Summary
- The widest gap is in coding, where GPT-5.3 Codex leads 48.6 to 43.5.
- Longcat Flash Chat has downloadable open weights; the other is API-only.
Side by side
| GPT-5.3 Codex | Longcat Flash Chat | |
|---|---|---|
| Provider | OpenAI | Meituan |
| Noometry Index | 45.8 | 42.1 |
| Released | 2026-02-05 | — |
| Weights | Proprietary | Open |
| Context window | 400K | — |
| Max output | 128K | — |
| Input $ / M tokens | $1.75 | — |
| Output $ / M tokens | $14 | — |
| Results tracked | 8 | 19 |
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Category by category
Coding GPT-5.3 Codex leads
GPT-5.3 Codex: 48.6 (#56), Longcat Flash Chat: 43.5 (#87)
| Benchmark | GPT-5.3 Codex | Longcat Flash Chat |
|---|---|---|
| SWE-bench Verified | 74.8% | — |
| LMArena WebDev | 1409 | — |
| WeirdML | 79.3% | — |
| LMArena Coding | — | 1471 |
| ALE-Bench | 1,655 | — |
Agentic & Tool Use Not comparable
GPT-5.3 Codex: 48.0 (#9), Longcat Flash Chat: —
| Benchmark | GPT-5.3 Codex | Longcat Flash Chat |
|---|---|---|
| Terminal-Bench | 78.4% | — |
| METR Time Horizons | 74.5% | — |
| Vending-Bench 2 | 5,940 | — |
Reasoning Not comparable
GPT-5.3 Codex: —, Longcat Flash Chat: 19.0 (#272)
| Benchmark | GPT-5.3 Codex | Longcat Flash Chat |
|---|---|---|
| Kagi LLM Benchmark | — | 43.9% |
| NYT Connections (extended) | — | 17.7% |
| LMArena Hard Prompts | — | 1440 |
| Epoch Capabilities Index | 156.77 | — |
Math Not comparable
GPT-5.3 Codex: —, Longcat Flash Chat: 39.4 (#107)
| Benchmark | GPT-5.3 Codex | Longcat Flash Chat |
|---|---|---|
| LMArena Math | — | 1442 |
Knowledge Not comparable
GPT-5.3 Codex: —, Longcat Flash Chat: 40.6 (#116)
| Benchmark | GPT-5.3 Codex | Longcat Flash Chat |
|---|---|---|
| LMArena Expert | — | 1454 |
Multilingual Not comparable
GPT-5.3 Codex: —, Longcat Flash Chat: 51.9 (#101)
| Benchmark | GPT-5.3 Codex | Longcat Flash Chat |
|---|---|---|
| LMArena Non-English | — | 1404 |
| LMArena Chinese | — | 1465 |
| LMArena French | — | 1456 |
| LMArena German | — | 1408 |
| LMArena Japanese | — | 1373 |
| LMArena Korean | — | 1371 |
| LMArena Russian | — | 1395 |
| LMArena Spanish | — | 1445 |
Instruction Following Not comparable
GPT-5.3 Codex: —, Longcat Flash Chat: 74.4 (#96)
| Benchmark | GPT-5.3 Codex | Longcat Flash Chat |
|---|---|---|
| LMArena Instruction Following | — | 1411 |
Long Context Not comparable
GPT-5.3 Codex: —, Longcat Flash Chat: 43.5 (#93)
| Benchmark | GPT-5.3 Codex | Longcat Flash Chat |
|---|---|---|
| LMArena Longer Query | — | 1425 |
Writing & Preference Not comparable
GPT-5.3 Codex: —, Longcat Flash Chat: 61.0 (#91)
| Benchmark | GPT-5.3 Codex | Longcat Flash Chat |
|---|---|---|
| LMArena Text | — | 1427 |
| LMArena Creative Writing | — | 1388 |
| LMArena Multi-Turn | — | 1418 |
Frequently asked questions
Is GPT-5.3 Codex better than Longcat Flash Chat?
GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 42.1 on the Noometry Index.
Is GPT-5.3 Codex or Longcat Flash Chat better for coding?
GPT-5.3 Codex scores higher on coding benchmarks: 48.6 versus 43.5 in the Noometry coding category.
How many benchmarks do GPT-5.3 Codex and Longcat Flash Chat share?
0 benchmarks have published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and Longcat Flash Chat has 19.