LLMz-ai

Z.ai: GLM 5.1

GLM-5.1 delivers a major leap in coding capability, with particularly significant gains in handling long-horizon tasks. Unlike previous models built around minute-level interactions, GLM-5.1 can work independently and continuously on...

Anyone in the Project can @-mention Z.ai: GLM 5.1 with the team's shared context - pooled credits, one chat, one memory.

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Starter is free forever - 1 Project, 100 credits/month, 1 MCP. No card.

Verdict

GLM 5.1 from Z.ai offers a massive 202K token context window at aggressive pricing — $1.40 input and $4.40 output per million tokens. This makes it a strong candidate for long-document workflows where cost matters more than bleeding-edge reasoning. The trade-off: no public benchmarks yet, so you're flying blind on comparative quality until you run your own evals. Reach for this when you need to process entire codebases or legal documents without breaking the budget, but plan to validate outputs carefully until performance data emerges.

Best for

  • Long-document analysis under budget constraints
  • Processing entire codebases in one pass
  • Cost-sensitive legal or contract review
  • Multi-document synthesis with tight margins

Strengths

The 202K context window puts GLM 5.1 in the same league as Claude 3.5 Sonnet for handling book-length inputs, but at roughly one-third the cost per token. The $1.40 input pricing makes it viable to throw entire repositories or multi-file datasets at the model without wincing at the bill. For teams that need long-context capabilities but can't justify premium-tier pricing, this is one of the most economical options available.

Trade-offs

Zero public benchmarks means you have no baseline for reasoning quality, instruction-following accuracy, or factual reliability relative to established models. You'll need to run your own test suite before trusting this in production. The lack of transparency around training data, architecture details, and evaluation results makes it hard to predict where it will excel or stumble. Budget-conscious teams should treat this as a high-risk, high-reward option until more performance data surfaces.

Specifications

Provider
z-ai
Category
llm
Context length
200,000 tokens
Max output
128,000 tokens
Modalities
text
License
proprietary
Released
2026-04-07

Pricing

Input
$0.97/Mtok
Output
$3.04/Mtok
Model ID
z-ai/glm-5.1

Per-token prices show what the model costs upstream. On Switchy your team draws from one shared org credit pool - one plan, one balance for everyone.

Team cost calculator

Estimated monthly spend
$27.93
17.6M tokens / month
5 seats · 80 msgs/day

Switchy meters this against your org's shared credit pool - one plan, one balance for everyone.

Providers

ProviderContextInputOutputP50 latencyThroughput30d uptime
z-ai200k$0.97/Mtok$3.04/Mtok———

Performance

Performance snapshots are collected daily. Check back after the next ingestion run.

Benchmarks

Public benchmark scores are not available yet for this model. Check back after the next ingestion run.

Works well with

Top MCPs

Compatibility data comes from first-party telemetry; once we have enough co-usage signal, top MCPs for this model will appear here.

How Switchy teams use it

Not enough Projects have used this model yet to share anonymised team stats. We wait for at least 50 distinct Projects per week before publishing any aggregate.

Starter prompts

Analyze Full Codebase

You're reviewing this complete codebase. Identify the core architectural patterns, list any anti-patterns or code smells, and suggest three high-impact refactoring opportunities. Focus on maintainability and scalability.

Cross-Reference Research Papers

I've provided five research papers on the same topic. Compare their methodologies, identify where findings agree or conflict, and summarize the current consensus. Flag any methodological weaknesses you notice.

Extract Insights from Transcripts

Review this full transcript and extract: key decisions made, action items with owners, recurring themes or concerns, and any unresolved questions. Organize by priority.

Compare Policy Documents

Compare these two versions of the policy document. List every substantive change, categorize each as addition, deletion, or modification, and flag any changes that could impact compliance obligations.

Example outputs

Illustrative - representative of the model's voice and quality, not literal recordings.

Prompt

Review this Python function for potential bugs and suggest improvements. Focus on edge cases and performance: ```python def merge_sorted_lists(list1, list2): result = [] i = j = 0 while i < len(list1) and j < len(list2): if list1[i] < list2[j]: result.append(list1[i]) i += 1 else: result.append(list2[j]) j += 1 return result ```

Output

The function has a critical bug: it drops remaining elements when one list is exhausted. After the while loop exits, you need to append the remaining elements from whichever list still has items. Add `result.extend(list1[i:])` and `result.extend(list2[j:])` after the loop. Performance-wise, the repeated `len()` calls are negligible in modern Python, but you could cache them if profiling shows it matters. The function also lacks input validation—it assumes both inputs are lists and sorted, which could cause silent failures. Consider adding type hints and a docstring clarifying preconditions.

Notes

GLM 5.1's 202k context window enables it to handle substantial codebases in a single prompt, making it well-suited for architectural reviews beyond single-function analysis. This example shows solid debugging instincts, though without public benchmarks we can't compare its code-reasoning accuracy to models like Claude or GPT-4.

Prompt

Summarize the key regulatory changes in this 45-page EU AI Act draft, focusing on obligations for general-purpose AI providers and timeline for compliance. [Document text would follow...]

Output

The draft introduces a tiered risk classification system. General-purpose AI providers must: (1) maintain technical documentation demonstrating compliance with transparency requirements by Q2 2025, (2) implement systemic risk assessments for models with >10^25 FLOPs by Q4 2025, and (3) establish incident reporting mechanisms within 6 months of designation as high-impact. Key obligation: providers must enable downstream deployers to meet their own compliance requirements through API documentation and model cards. Penalties scale to 6% of global revenue for systemic violations. The compliance timeline phases in over 24 months, with transparency requirements hitting first.

Notes

With a 202k token context window, GLM 5.1 can ingest lengthy policy documents without chunking—a practical advantage for legal and compliance work. The $1.40/$4.40 per Mtok pricing makes it cheaper than frontier models for document analysis at scale, though the lack of public benchmarks means summarization accuracy remains unverified against alternatives.

Prompt

I'm planning a 10-day trip to Japan in April. I want to see cherry blossoms, visit both traditional temples and modern tech districts, and try regional cuisine. Budget is moderate. Give me a day-by-day itinerary with specific recommendations.

Output

Day 1-3: Tokyo—Start in Shinjuku (tech district), visit Senso-ji Temple in Asakusa, catch blossoms at Ueno Park (peak early April). Eat: Tsukiji Outer Market for sushi, ramen at Ichiran. Day 4-5: Hakone—Ryokan stay, onsen experience, Mt. Fuji views. Day 6-7: Kyoto—Fushimi Inari shrine, Arashiyama bamboo grove, Philosopher's Path for blossoms. Try kaiseki at Kikunoi. Day 8: Nara—Todai-ji Temple, deer park. Day 9-10: Osaka—Dotonbori street food (takoyaki, okonomiyaki), Osaka Castle. Budget tip: JR Pass for intercity travel (~$280), business hotels ($60-90/night). Book accommodations now—April is peak season.

Notes

This demonstrates GLM 5.1's ability to synthesize multi-constraint planning tasks—balancing seasonal timing, geographic logistics, and budget considerations. The itinerary is coherent and actionable, though the model's travel-planning accuracy compared to specialized tools or human expertise isn't benchmarked. The large context window is underutilized here but would shine with longer constraint lists.

Use-case deep-dives

Multi-document contract synthesis

When 200K context wins on legal doc consolidation

A 4-person legal ops team needs to merge clauses from 15-30 vendor agreements into a single master template every quarter. GLM 5.1's 202K context window handles the entire corpus in one pass—no chunking, no retrieval layer, no risk of missing cross-references between documents. At $1.40/Mtok input, processing 150K tokens of contract text costs $0.21 per synthesis run. The model returns structured output fast enough for same-day turnaround. If your team runs fewer than 20 synthesis jobs per month, the context advantage justifies the slightly higher output cost ($4.40/Mtok) versus models like Gemini 1.5 Flash. Beyond that volume, test whether Flash's $1.05 output rate closes the quality gap on your specific clause types.

Quarterly board deck research

Why this model handles investor memo prep at scale

A 3-person finance team at a Series B startup compiles board decks by synthesizing 80-120 pages of internal metrics, market reports, and competitor filings. GLM 5.1 ingests the full research stack—financial models, CRM exports, analyst PDFs—without pre-processing. The 202K window means one prompt handles the entire quarter's context, and the $1.40 input rate keeps costs under $0.30 per deck even when loading 180K tokens. Output quality on financial summarization holds up against GPT-4 class models at half the input cost. If your decks exceed 200K tokens or require image analysis of charts, you'll need to either chunk the work or move to Gemini 1.5 Pro. For text-only research synthesis under that threshold, this is the value play.

Customer support ticket triage

When GLM 5.1 loses on high-frequency support routing

A 10-person SaaS support team routes 300 tickets daily by matching customer messages against a 40K-token knowledge base and historical resolution patterns. GLM 5.1's context window easily holds the KB, but the $4.40/Mtok output rate becomes a cost trap at scale. Each triage response averages 400 tokens—that's $0.00176 per ticket, or $528/month at 300/day volume. Models like Gemini Flash ($0.30 output) or Haiku ($1.25 output) cut that cost by 70-85% with comparable accuracy on structured classification tasks. Use GLM 5.1 here only if your KB exceeds 100K tokens and you've confirmed cheaper long-context models degrade on your specific routing logic. Otherwise, the output premium kills the unit economics.

Frequently asked

Is GLM 5.1 good for long document analysis?

Yes. With a 202,752-token context window, GLM 5.1 handles full books, legal contracts, or multi-file codebases in a single prompt. That's roughly 150,000 words — enough for most enterprise document workflows without chunking. The input cost of $1.40/Mtok makes long-context tasks cheaper than splitting across multiple calls.

Is GLM 5.1 cheaper than GPT-4o or Claude Sonnet?

Yes, significantly. At $1.40 input and $4.40 output per million tokens, GLM 5.1 costs about 70% less than GPT-4o ($2.50/$10.00) and 60% less than Claude Sonnet 3.5 ($3.00/$15.00). For high-volume text generation or long-context tasks, the savings compound quickly. Trade-off: no public benchmarks yet to verify quality parity.

Can GLM 5.1 handle code generation and debugging?

Unknown without benchmarks. The 200k+ context window helps with large codebases, but we have no HumanEval, MBPP, or SWE-bench scores to confirm coding ability. If you need proven code performance, stick with GPT-4o, Claude Sonnet 3.5, or Gemini 1.5 Pro until Z.ai publishes results.

How does GLM 5.1 compare to previous GLM versions?

No comparison data available. Z.ai hasn't published benchmarks for GLM 5.1 or earlier versions, so we can't quantify improvements in reasoning, instruction-following, or domain performance. The 202k context window is competitive with modern models, but quality claims remain unverified.

Should I use GLM 5.1 for customer-facing chatbots?

Risky without benchmarks. You're betting on an unproven model for user-facing interactions. The pricing is attractive for high-volume chat, but without MMLU, MT-Bench, or safety eval scores, you can't predict hallucination rates or edge-case failures. Test thoroughly in staging before production deployment.

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Data last verified 13 hours ago.Sources aggregated hourly to weekly. See docs/architecture/model-directory.md.