LongCat Flash Lite vs GPT-5.3 Codex (xhigh): Which AI Model Is Better?

Updated March 26, 2026· Based on independent benchmark data

Quick Verdict

GPT-5.3 Codex (xhigh) leads in intelligence with a score of 54.0 vs 23.9. For speed, LongCat Flash Lite wins at 125 tok/s vs 72 tok/s.

Head-to-Head Comparison

Metric	LongCat Flash Lite	GPT-5.3 Codex (xhigh)
Intelligence Score	23.9	54.0
Coding Score	16.5	53.1
Math Score	N/A	N/A
Speed (tok/s)	125 tok/s	72 tok/s
Latency (TTFT)	3.04s	83.91s
Input Price / 1M tokens	Free	$1.75
Output Price / 1M tokens	Free	$14
Context Window	N/A	N/A
Max Output Tokens	N/A	N/A
Input Modalities	Text	Text

Detailed Analysis

Intelligence & Quality

GPT-5.3 Codex (xhigh) outperforms LongCat Flash Lite on the intelligence index with a score of 54.0 compared to 23.9. For coding tasks, GPT-5.3 Codex (xhigh) has the edge with a coding score of 53.1 vs 16.5.

Speed & Latency

LongCat Flash Lite generates output significantly faster at 125 tok/s compared to GPT-5.3 Codex (xhigh)'s 72 tok/s, making it 1.7x faster for streaming responses. Time to first token is 3.04s for LongCat Flash Lite vs 83.91s for GPT-5.3 Codex (xhigh), which affects perceived responsiveness in interactive applications.

Pricing

LongCat Flash Lite is completely free, while GPT-5.3 Codex (xhigh) costs $1.75/1M input tokens and $14/1M output tokens.

Best Use Cases

Choose LongCat Flash Lite when you need faster output (125 tok/s). Choose GPT-5.3 Codex (xhigh) when you need higher intelligence (54.0), stronger coding performance (53.1).

Choose LongCat Flash Lite if:

✓You need faster throughput (125 tok/s vs 72 tok/s)
✓You want lower latency (3.04s vs 83.91s TTFT)
✓You want zero cost (Free vs paid)

Choose GPT-5.3 Codex (xhigh) if:

✓You need higher intelligence (score: 54.0 vs 23.9)
✓You prioritize coding performance (score: 53.1 vs 16.5)

Frequently Asked Questions

Is LongCat Flash Lite better than GPT-5.3 Codex (xhigh) for coding?

GPT-5.3 Codex (xhigh) scores higher on coding benchmarks (53.1 vs 16.5), making it the better choice for programming tasks.

Is LongCat Flash Lite faster than GPT-5.3 Codex (xhigh)?

LongCat Flash Lite is faster, producing output at 125 tok/s compared to GPT-5.3 Codex (xhigh)'s 72 tok/s.

Can LongCat Flash Lite process images?

No, LongCat Flash Lite does not support image input. Neither model supports image input.

Should I use LongCat Flash Lite or GPT-5.3 Codex (xhigh)?

It depends on your priorities. GPT-5.3 Codex (xhigh) scores higher on intelligence (54.0), but LongCat Flash Lite may be better for specific use cases like cost savings or speed-critical applications.

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View LongCat Flash Litedetails →View GPT-5.3 Codex (xhigh)details →Full pricing comparison →

Data last synced: March 26, 2026