GLM-5.1 is Z.ai's flagship open-weight model, released in April 2026 with a sparse Mixture of Experts architecture totaling 754 billion parameters and roughly 40 billion active per token. It supports a 202,752-token context window and can generate up to 128,000 tokens per response, suiting it to long document analysis and extended code generation. Built for autonomous software engineering, GLM-5.1 reports a state-of-the-art 58.4 on SWE-Bench Pro, ahead of Claude Opus 4.6 (57.3) and GPT-5.4 (57.7), and is designed for multi-step agentic workflows where it can sustain a single task for up to eight hours across planning, execution, testing, and refinement. Rather than single-pass generation, it iteratively drafts, evaluates, and revises solutions toward production-ready code. Released under the MIT license on Hugging Face, GLM-5.1 supports function calling, thinking modes, structured output, context caching, and tool use, and can be self-hosted, fine-tuned, and deployed commercially without restrictive licensing terms. Stronger on coding and agentic tasks than on broad general reasoning, GLM-5.1 also handles multilingual content and supports streaming output during tool execution for real-time development feedback.
GLM 5.1 runs on 5 different routes through the Opper gateway. Compare residency, ZDR, and training posture at a glance โ full data-handling detail per route below.
| Provider | Region | Zero data retention | Training | Input | Output |
|---|---|---|---|---|---|
| Alibaba Cloud | EU | Enterprise | No | $0.82 | $3.30 |
| DeepInfra | US | Enterprise | No | $1.05 | $3.50 |
| Fireworks | US | Enterprise | No | $1.40 | $4.40 |
| Nebius | EU | Enterprise | No | $1.40 | $4.40 |
| Novita | US | Enterprise | No | $1.38 | $4.40 |
Training posture across routes: No training on prompts by default.
Each route hosting GLM 5.1 has its own privacy posture, residency, and GDPR terms. Postures are maintained by Opper with a last-verification timestamp.
Zero data retention is available via Opper Enterprise contract. No training on customer data. EU; DPA available.
Zero data retention is available via Opper Enterprise contract. No training on customer data. US; unknown.
Zero data retention is available via Opper Enterprise contract. No training on customer data. US; SCCs; DPA available.
Zero data retention is available via Opper Enterprise contract. No training on customer data. EU; DPA available.
Zero data retention is available via Opper Enterprise contract. No training on customer data. US; SCCs; DPA available.
Independent benchmark scores โ composite indices for reasoning, coding, and math, plus individual eval scores where available.
Call GLM 5.1 through the Opper gateway with one API key. Let your coding agent set it up, or call it directly โ Opper is drop-in compatible with the OpenAI, Anthropic, and Google AI SDKs.
Copy this and paste it into your coding agent โ Claude Code, Cursor, Codex, and more โ and it'll wire up Opper for you.
import OpenAI from "openai";const client = new OpenAI({apiKey: process.env.OPPER_API_KEY,baseURL: "https://api.opper.ai/v3/compat",});const completion = await client.chat.completions.create({model: "alibaba:eu/glm-5.1",messages: [{ role: "user", content: "Hello" }],});console.log(completion.choices[0].message.content);
Side-by-side on privacy, EU hosting, pricing, and benchmarks.
