glm-5.1 vs glm-5.3-flash
Side-by-side comparison of glm-5.1 and glm-5.3-flash: benchmarks, pricing, context window and capabilities. Both are accessible through Requesty's unified API. glm-5.3-flash outperforms glm-5.1 on 4 of 4 shared benchmarks.
glm-5.1
Input / 1M
$1.40
Output / 1M
$4.40
Context
200K
Model ID
zai/glm-5.1
glm-5.3-flash
Input / 1M
$0.15$0.07
Output / 1M
$0.50$0.25
Context
1M
Model ID
zai/glm-5.3-flash
Benchmark comparison
Intelligence Indexreasoning
glm-5.131.9%
glm-5.3-flash46.2%
Coding Indexcoding
glm-5.155.8%
glm-5.3-flash71.5%
GPQA Diamondreasoning
glm-5.186.8%
glm-5.3-flash91.2%
Terminal-Bench Hardagentic
glm-5.143.2%
glm-5.3-flashN/A
τ²-Benchagentic
glm-5.197.7%
glm-5.3-flashN/A
SciCodecoding
glm-5.1N/A
glm-5.3-flash51.6%
Humanity's Last Examreasoning
glm-5.130.1%
glm-5.3-flash39.9%
Scores sourced from official model cards, Artificial Analysis, and public leaderboards. Benchmarks measure specific skills and don't capture every aspect of model quality.
Pricing & specifications
| glm-5.1 | glm-5.3-flash | |
|---|---|---|
| Input price / 1M | $1.40 | $0.15$0.07 |
| Output price / 1M | $4.40 | $0.50$0.25 |
| Context window | 200K tokens | 1M tokens |
| Max output | 128K tokens | 128K tokens |
| Vision input | N/A | Yes |
| Tool calling | Yes | Yes |
| Reasoning | Yes | Yes |
| Prompt caching | Yes | Yes |
| Computer use | N/A | N/A |
| Provider | Z.ai | Z.ai |
Questions people ask
Is glm-5.1 better than glm-5.3-flash?
glm-5.3-flash outperforms glm-5.1 on 4 of 4 shared benchmarks. See the benchmark comparison above for specifics: glm-5.1 and glm-5.3-flash have different strengths across reasoning, coding, math and multimodal tasks.
Which is cheaper, glm-5.1 or glm-5.3-flash?
glm-5.3-flash is cheaper. glm-5.1 costs $1.40/$4.40 per 1M input/output tokens, while glm-5.3-flash costs $0.07/$0.25. The prices shown are what you pay: glm-5.3-flash runs at 50% off its list rate of $0.15 per 1M input and $0.50 per 1M output until 9 Sep 2026.
Can I use glm-5.1 and glm-5.3-flash through the same API?
Yes. Requesty provides a single OpenAI-compatible API that routes to both. Change just the "model" parameter to switch between "zai/glm-5.1" and "zai/glm-5.3-flash", no other code changes needed.
What are the context windows?
glm-5.1 supports up to 200K tokens of context. glm-5.3-flash supports up to 1M tokens. Longer context means you can feed larger documents or codebases in a single prompt, though quality often degrades past 128K for most models.
Switch between glm-5.1 and glm-5.3-flash with one line of code
Requesty provides a single OpenAI-compatible API for 600+ models. Change the model parameter, not your code.