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GLM-5.3-Flash vs GPT-5 Codex

Comparing GLM-5.3-Flash and GPT-5 Codex across benchmarks, pricing, and capabilities.

Zhipu AI · OpenAI · Updated for 2026

Which is better?

GLM-5.3-Flash and GPT-5 Codex trade strengths across price, capabilities, and technical limits. The better choice depends on the workload.

Based on current benchmark, pricing, and model metadata for 2026.

Choose GLM-5.3-Flash

  • you want the most recent training data — it shipped Aug 2026
  • you need open weights you can self-host or fine-tune

Choose GPT-5 Codex

  • you are already invested in the OpenAI ecosystem

At a glance

The differences that matter most.

GLM-5.3-Flash
Zhipu AI
GPT-5 Codex
OpenAI
Benchmark wins
—
—
Input price
$0.15 / M
— / M
Output price
$0.50 / M
— / M
Context window
1,048,576
—
Released
Aug 2026
Sep 2025
License
MIT
Proprietary

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

GLM-5.3-Flash and GPT-5 Codexdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Arena Performance

Playground indexes and blind preference scores

Context Window

Maximum input and output token capacity

Only GLM-5.3-Flash specifies input context (1,048,576 tokens). Only GLM-5.3-Flash specifies output context (131,072 tokens).

Zhipu AI
GLM-5.3-Flash
Input1,048,576 tokens
Output131,072 tokens
OpenAI
GPT-5 Codex
Input- tokens
Output- tokens
Thu Aug 27 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

GLM-5.3-Flash supports multimodal inputs, whereas GPT-5 Codex does not.

GLM-5.3-Flash can handle both text and other forms of data like images, making it suitable for multimodal applications.

GLM-5.3-Flash

Text
Images
Audio
Video

GPT-5 Codex

Text
Images
Audio
Video

License

Usage and distribution terms

GLM-5.3-Flash is licensed under MIT, while GPT-5 Codex uses a proprietary license.

License differences may affect how you can use these models in commercial or open-source projects.

GLM-5.3-Flash

MIT

Open weights

GPT-5 Codex

Proprietary

Closed source

Release Timeline

When each model was launched

GLM-5.3-Flash was released on 2026-08-26, while GPT-5 Codex was released on 2025-09-15.

GLM-5.3-Flash is 12 months newer than GPT-5 Codex.

GLM-5.3-Flash

Aug 26, 2026

1 days ago

11mo newer
GPT-5 Codex

Sep 15, 2025

11 months ago

Knowledge Cutoff

When training data ends

GPT-5 Codex has a documented knowledge cutoff of 2024-09-30, while GLM-5.3-Flash's cutoff date is not specified.

We can confirm GPT-5 Codex's training data extends to 2024-09-30, but cannot make a direct comparison without GLM-5.3-Flash's cutoff date.

GLM-5.3-Flash

—

GPT-5 Codex

Sep 2024

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against GLM-5.3-Flash and GPT-5 Codex side-by-side, then vote on the output you prefer.

GLM-5.3-Flash
✓ Preferred
GPT-5 Codex
Open in Playground

FAQ

Common questions about GLM-5.3-Flash vs GPT-5 Codex.

Which is better, GLM-5.3-Flash or GPT-5 Codex?

GLM-5.3-Flash (Zhipu AI) and GPT-5 Codex (OpenAI) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does GLM-5.3-Flash compare to GPT-5 Codex in benchmarks?

GLM-5.3-Flash scores CharXiv-R: 89.4%, Terminal-Bench 2.1: 84.3%, MMVU: 80.5%, Toolathlon: 78.4%, Chartography: 78.0%. GPT-5 Codex scores SWE-Bench Verified: 74.5%.

What are the context window sizes for GLM-5.3-Flash and GPT-5 Codex?

GLM-5.3-Flash supports 1.0M tokens and GPT-5 Codex 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 GLM-5.3-Flash and GPT-5 Codex?

Key differences include multimodal support (yes vs no), licensing (MIT vs Proprietary). See the full comparison above for benchmark-by-benchmark results.

Who makes GLM-5.3-Flash and GPT-5 Codex?

GLM-5.3-Flash is developed by Zhipu AI and GPT-5 Codex is developed by OpenAI.

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