GLM-5.1 vs Grok 4
GLM-5.1 (2026) and Grok 4 (2026) are frontier-tier reasoning models from Zhipu AI and xAI. GLM-5.1 ships a 200k-token context window, while Grok 4 ships a 256k-token context window. On pricing, GLM-5.1 costs $0.95/1M input tokens versus $3/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing.
GLM-5.1 is ~216% cheaper at $0.95/1M; pay for Grok 4 only for coding workflow support.
Specs
Pricing and availability
| GLM-5.1 | Grok 4 | |
|---|---|---|
| Input price | $0.95/1M tokens | $3/1M tokens |
| Output price | $3.15/1M tokens | $15/1M tokens |
| Providers |
Capabilities
| GLM-5.1 | Grok 4 | |
|---|---|---|
| Vision | ||
| Multimodal | ||
| Reasoning | ||
| Function calling | ||
| Tool use | ||
| Structured outputs | ||
| Code execution |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on multimodal input: Grok 4, function calling: GLM-5.1, and tool use: GLM-5.1. Both models share reasoning mode, structured outputs, and code execution, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, GLM-5.1 lists $0.95/1M input and $3.15/1M output tokens, while Grok 4 lists $3/1M input and $15/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts GLM-5.1 lower by about $4.99 per million blended tokens. Availability is 2 providers versus 3, so concentration risk also matters.
Choose GLM-5.1 when coding workflow support and lower input-token cost are central to the workload. Choose Grok 4 when coding workflow support, larger context windows, and broader provider choice are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency.
FAQ
Which has a larger context window, GLM-5.1 or Grok 4?
Grok 4 supports 256k tokens, while GLM-5.1 supports 200k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is cheaper, GLM-5.1 or Grok 4?
GLM-5.1 is cheaper on tracked token pricing. GLM-5.1 costs $0.95/1M input and $3.15/1M output tokens. Grok 4 costs $3/1M input and $15/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is GLM-5.1 or Grok 4 open source?
GLM-5.1 is listed under Proprietary. Grok 4 is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for multimodal input, GLM-5.1 or Grok 4?
Grok 4 has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for reasoning mode, GLM-5.1 or Grok 4?
Both GLM-5.1 and Grok 4 expose reasoning mode. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Where can I run GLM-5.1 and Grok 4?
GLM-5.1 is available on Z.ai and OpenRouter. Grok 4 is available on Microsoft Foundry, OpenRouter, and Replicate API. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-04-24. Data sourced from public model cards and provider documentation.