GLM-5.1 vs o3 Mini
GLM-5.1 (2026) and o3 Mini (2025) are frontier-tier reasoning models from Zhipu AI and OpenAI. GLM-5.1 ships a 200k-token context window, while o3 Mini ships a 200k-token context window. On Google-Proof Q&A, GLM-5.1 leads by 6.5 pts. On pricing, GLM-5.1 costs $0.98/1M input tokens versus $1.10/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Pick GLM-5.1 for reasoning; o3 Mini is better when coding workflow support matters more.
Decision scorecard
Local evidence first| Signal | GLM-5.1 | o3 Mini |
|---|---|---|
| Best for | reasoning-heavy apps, tool-calling agents, and provider-routed production | reasoning-heavy apps, tool-calling agents, and provider-routed production |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 200k | 200k |
| Cheapest output | $3.08/1M tokens | $4.40/1M tokens |
| Provider routes | 5 tracked | 4 tracked |
| Shared benchmarks | Google-Proof Q&A leader | 2 rows |
Decision tradeoffs
- GLM-5.1 holds a shared-benchmark lead on Google-Proof Q&A, ahead by 6.5 points.
- GLM-5.1 has the lower cheapest tracked output price at $3.08/1M tokens.
- GLM-5.1 has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags GLM-5.1 for Coding, RAG, and Agents.
- Local decision data tags o3 Mini for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
GLM-5.1
$1,554
Cheapest tracked route/tier: Z.ai
o3 Mini
$1,980
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $426. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
- o3 Mini is $1.32/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
- GLM-5.1 is $1.32/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-07 | 2025-01-31 |
| Context window | 200k | 200k |
| Parameters | 754B total, 40B active | — |
| Architecture | mixture of experts | decoder only |
| License | MIT(OSI) | Proprietary |
| Openness | Open source | Proprietary |
| Commercial use | Commercial use allowed | Commercial use with conditions |
| Knowledge cutoff | 2025-11 | 2025-04 |
Pricing and availability
| Pricing attribute | GLM-5.1 | o3 Mini |
|---|---|---|
| Input price | $0.98/1M tokens | $1.10/1M tokens |
| Output price | $3.08/1M tokens | $4.40/1M tokens |
| Providers |
Capabilities
| Capability | GLM-5.1 | o3 Mini |
|---|---|---|
| Vision | No | No |
| Multimodal | No | No |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | GLM-5.1 | o3 Mini |
|---|---|---|
| Google-Proof Q&A | 86.2 | 79.7 |
| Chatbot Arena | 1472.0 | 1335.0 |
Deep dive
On shared benchmark coverage, Google-Proof Q&A has GLM-5.1 at 86.2 and o3 Mini at 79.7, with GLM-5.1 ahead by 6.5 points; Chatbot Arena has GLM-5.1 at 1472 and o3 Mini at 1335, with GLM-5.1 ahead by 137 points. The largest visible gap is 137 points on Chatbot Arena, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint is close: both models cover reasoning mode, function calling, tool use, structured outputs, and code execution. That makes context budget, benchmark fit, and provider maturity more important than a simple checklist. If your application depends on one integration detail, verify it against the provider route you plan to use, not just the base model listing.
For cost, GLM-5.1 lists $0.98/1M input and $3.08/1M output tokens on the cheapest tracked provider, while o3 Mini lists $1.10/1M input and $4.40/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts GLM-5.1 lower by about $0.48 per million blended tokens. Availability is 5 providers versus 4, so concentration risk also matters.
Choose GLM-5.1 when coding workflow support, lower input-token cost, and broader provider choice are central to the workload. Choose o3 Mini when coding workflow support are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, GLM-5.1 or o3 Mini?
GLM-5.1 supports 200k tokens, while o3 Mini 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 o3 Mini?
GLM-5.1 is cheaper on tracked token pricing. GLM-5.1 costs $0.98/1M input and $3.08/1M output tokens. o3 Mini costs $1.10/1M input and $4.40/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is GLM-5.1 or o3 Mini open source?
GLM-5.1 is listed under MIT. o3 Mini 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 reasoning mode, GLM-5.1 or o3 Mini?
Both GLM-5.1 and o3 Mini 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.
Which is better for function calling, GLM-5.1 or o3 Mini?
Both GLM-5.1 and o3 Mini expose function calling. 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 o3 Mini?
GLM-5.1 is available on Z.ai, OpenRouter, Fireworks AI, Vercel AI Gateway, and Novita AI. o3 Mini is available on OpenRouter, Azure OpenAI, OpenAI API, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-06-04. Data sourced from public model cards and provider documentation.