GLM-5.1 vs GPT Realtime
GLM-5.1 and GPT Realtime are both current production-tier models. GLM-5.1 is meaningfully cheaper at $1 / $3.2 per 1M. GLM-5.1 leads on coding, reasoning, long-context retrieval.
Specs side by side
| Metric | Z.ai GLM-5.1 | OpenAI GPT Realtime |
|---|---|---|
| Input price (per 1M) | $1 | $4 |
| Output price (per 1M) | $3.2 | $16 |
| Context window | 200k tokens | 128k tokens |
| Speed tier | balanced | ultra |
| Open weights | Yes | No |
| EU region | No | Yes |
| Free tier | bigmodel.cn | No |
| Prompt caching | No | No |
| Vision input | No | No |
| Extended thinking | Yes | No |
When to choose each
Choose GLM-5.1 if…
- Cost is a priority ($1 / $3.2 per 1M vs $4 / $16 per 1M)
- You need open weights for self-hosting or fine-tuning
- You want a free tier for prototyping
- Coding is central to your workload
- Reasoning is central to your workload
Choose GPT Realtime if…
- Low latency matters (ultra vs balanced)
- EU data residency is required
- You need realtime speech-to-speech
Benchmark delta
GLM-5.1 leads on
- Coding
- Reasoning
- Long-context retrieval
- Multilingual
GPT Realtime leads on
GPT Realtime has no meaningful benchmark lead in this pair.
FAQ — GLM-5.1 vs GPT Realtime
GLM-5.1 vs GPT Realtime — which is better?
GLM-5.1 and GPT Realtime are both current production-tier models. GLM-5.1 is meaningfully cheaper at $1 / $3.2 per 1M. GLM-5.1 leads on coding, reasoning, long-context retrieval. The right pick depends on your use case — see "When to choose each" above for a data-driven decision.
How does GLM-5.1 pricing compare to GPT Realtime?
GLM-5.1 costs $1 / $3.2 per 1M vs GPT Realtime at $4 / $16 per 1M. GLM-5.1 is cheaper on output tokens by roughly 400%.
Does GLM-5.1 or GPT Realtime have the bigger context window?
GLM-5.1 has a 200k-token context window — 2× the 128k context of GPT Realtime. Enough for long reports and multi-document analysis.
Is there a free tier for GLM-5.1 or GPT Realtime?
GLM-5.1: yes — Free tier with monthly token allowance. GPT Realtime: no — Paid-only.
Which is better for coding — GLM-5.1 or GPT Realtime?
GLM-5.1 leads on coding benchmarks (GLM-5.1: 93/100, GPT Realtime: 78/100). For production coding agents also weigh tool-use performance — GLM-5.1 scores 86, GPT Realtime scores 84.