GLM 5.1

• SWE-bench VerifiedCan the model fix real bugs in real open-source software projects? Share of tasks solved.74.2%#15 of 28
• GPQA DiamondVery hard multiple-choice questions in biology, physics and chemistry, written by PhD experts. Random guessing scores 25%.89.9%#33 of 116
• AIME mathCompetition-level math problems in the style of the American Invitational Mathematics Examination. Share solved.93.3%#35 of 112
• FrontierMathOriginal, unpublished math problems written by professional mathematicians, from advanced to research level. Share solved.36.8%#47 of 73
• SimpleQA VerifiedShort factual questions. Measures how often the model gets facts right instead of making something up.34.0%#47 of 69

Benchmark data: Epoch AI, licensed CC BY 4.0

Companies that serve this model through an API: 14. Prices per million tokens, cheapest first.

Availability and prices come from OpenRouter’s public API and are refreshed daily. Uptime is the share of successful requests over the last 24 hours. Some providers run a compressed version of open models (fp8, int4), which is cheaper but can be slightly less accurate.

Call GLM 5.1 through OpenRouter’s OpenAI-compatible API: create a key on openrouter.ai, then run one of these examples.

curl https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "z-ai/glm-5.1", "messages": [{"role": "user", "content": "Hello! What can you do?"}]}'

import os
from openai import OpenAI

client = OpenAI(base_url="https://openrouter.ai/api/v1", api_key=os.environ["OPENROUTER_API_KEY"])
reply = client.chat.completions.create(
    model="z-ai/glm-5.1",
    messages=[{"role": "user", "content": "Hello! What can you do?"}],
)
print(reply.choices[0].message.content)

import OpenAI from "openai";

const client = new OpenAI({ baseURL: "https://openrouter.ai/api/v1", apiKey: process.env.OPENROUTER_API_KEY });
const reply = await client.chat.completions.create({
  model: "z-ai/glm-5.1",
  messages: [{ role: "user", content: "Hello! What can you do?" }],
});
console.log(reply.choices[0].message.content);

The same code works with every model on this site: only the model ID changes. Many labs also offer their own API and SDK.

• 1,000 chat replies

  ≈ 500 tokens in, 300 out each
  $2.02
• Summarise a 100-page document

  ≈ 50,000 tokens in, 1,000 out
  $0.074
• An app with 10,000 requests a day for a month

  ≈ 1,000 tokens in, 400 out each
  $948

Cost calculator →

• Simon WillisonSep 29, 2026

  Quoting Anthropic Frontier Red Team

• ABC TecnologíaSep 18, 2026es

  ¿Quién puede permitirse frenar la IA?: el miedo a la extinción como estrategia de mercado

How much does GLM 5.1 cost?

GLM 5.1 costs $1.40 per million input tokens and $4.40 per million output tokens through the API. For example, 1,000 chat replies of about 500 tokens in and 300 out cost around $2.02.

What is the context window of GLM 5.1?

GLM 5.1 can read up to 204,800 tokens in one request, about 384 pages of text. It can write up to 131,072 tokens in a single answer.

Is GLM 5.1 open source?

Yes. Its weights are published (zai-org/GLM-5.1), so you can download it and run it on your own hardware, or use it through one of 14 API providers.

Who makes GLM 5.1?

GLM 5.1 is made by Z.ai (Zhipu). It became available through the API on April 7, 2026.

How good is GLM 5.1?

GLM 5.1 has an overall index of 149.9 in Epoch AI’s independent tests, ranking #47 of 136 models we track.

Can GLM 5.1 read images?

No. GLM 5.1 only accepts text as input.

What are the alternatives to GLM 5.1?

Models with a similar price from other companies include Qwen3.7 Max, Gemini 3.5 Flash and Mistral Medium 3.5. You can compare them side by side on this page.