The AI arena is free today

Open Superagent

GPT-5.1 Codex vs Seed 2.0 Lite

GPT-5.1 Codex and Seed 2.0 Lite are closely matched at 29.5 and 31.9 on the LLM Stats Score.

OpenAI · ByteDance · Updated for 2026

Which is better?

GPT-5.1 Codex and Seed 2.0 Lite are closely matched on the overall LLM Stats Score at 29.5 and 31.9.

In the 1 individual benchmarks reported for both models, GPT-5.1 Codex wins 1; this is a narrower head-to-head signal than the composite indexes.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose GPT-5.1 Codex

  • you value its reported benchmark strengths — it wins 1 of 1 exact shared results

Choose Seed 2.0 Lite

  • you want the most recent training data — it shipped Feb 2026

At a glance

The differences that matter most.

GPT-5.1 Codex
OpenAI
Seed 2.0 Lite
ByteDance
Core performance indexes
LLM Stats Score
29.5
#136
31.9
#116
Reasoning
29.6
#128
31.5
#115
Coding
20.9
#100
17.9
#122
Cost, coverage & limits
Benchmark wins
1 of 1
0 of 1
Input price
$1.25 / M
— / M
Output price
$10.00 / M
— / M
Context window
400,000
—

Individual benchmarks

3 reported for GPT-5.1 Codex · 5 for Seed 2.0 Lite

1 shared

GPT-5.1 Codex outperforms in 1 benchmarks (SWE-Bench Verified), while Seed 2.0 Lite is better at 0 benchmarks.

GPT-5.1 Codex significantly outperforms across most benchmarks.

Wed Oct 07 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only GPT-5.1 Codex specifies input context (400,000 tokens). Only GPT-5.1 Codex specifies output context (128,000 tokens).

OpenAI
GPT-5.1 Codex
Input400,000 tokens
Output128,000 tokens
ByteDance
Seed 2.0 Lite
Input- tokens
Output- tokens
Wed Oct 07 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both GPT-5.1 Codex and Seed 2.0 Lite support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

GPT-5.1 Codex

Text
Images
Audio
Video

Seed 2.0 Lite

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

GPT-5.1 Codex

Proprietary

Closed source

Seed 2.0 Lite

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5.1 Codex was released on 2025-11-19, while Seed 2.0 Lite was released on 2026-02-14.

Seed 2.0 Lite is 3 months newer than GPT-5.1 Codex.

GPT-5.1 Codex

Nov 19, 2025

10 months ago

Seed 2.0 Lite

Feb 14, 2026

7 months ago

2mo newer

Knowledge Cutoff

When training data ends

GPT-5.1 Codex has a knowledge cutoff of 2024-09-30, while Seed 2.0 Lite has a cutoff of 2024-01-01.

GPT-5.1 Codex has more recent training data (up to 2024-09-30), making it potentially better informed about events through that date compared to Seed 2.0 Lite (2024-01-01).

GPT-5.1 Codex

Sep 2024

8 mo newer
Seed 2.0 Lite

Jan 2024

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against GPT-5.1 Codex and Seed 2.0 Lite side-by-side, then vote on the output you prefer.

GPT-5.1 Codex
✓ Preferred
Seed 2.0 Lite
Open in Playground

FAQ

Common questions about GPT-5.1 Codex vs Seed 2.0 Lite.

Which is better, GPT-5.1 Codex or Seed 2.0 Lite?

GPT-5.1 Codex and Seed 2.0 Lite are closely matched on the LLM Stats Score at 29.5 and 31.9. GPT-5.1 Codex is made by OpenAI and Seed 2.0 Lite is made by ByteDance. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does GPT-5.1 Codex compare to Seed 2.0 Lite in benchmarks?

GPT-5.1 Codex scores SWE-Bench Verified: 73.7%, SWE-Lancer: 66.3%, Terminal-Bench 2.0: 52.8%. Seed 2.0 Lite scores AIME 2025: 93.0%, AIME 2026: 88.3%, GPQA: 85.1%, LiveCodeBench v6: 81.7%, SWE-Bench Verified: 73.5%.

What are the context window sizes for GPT-5.1 Codex and Seed 2.0 Lite?

GPT-5.1 Codex supports 400K tokens and Seed 2.0 Lite supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between GPT-5.1 Codex and Seed 2.0 Lite?

Key differences include LLM Stats Score (29.5 vs 31.9). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT-5.1 Codex and Seed 2.0 Lite?

GPT-5.1 Codex is developed by OpenAI and Seed 2.0 Lite is developed by ByteDance.

Related comparisons