How much does the GLM 5.3 Flash API cost?

On FastMetal, GLM 5.3 Flash is billed per token in yen: ¥13.19 per 1M input tokens and ¥43.98 per 1M output tokens, before tax. Usage is drawn from a prepaid balance; there is no subscription or monthly fee.

Can I call GLM 5.3 Flash with the OpenAI SDK?

Yes. Point base_url at https://api.fastmetal.ai/v1 and pass "glm-5.3-flash" as the model; existing OpenAI-style code works unchanged, including streaming, tool calls and structured output.

What is the context window of GLM 5.3 Flash?

1,310,720 tokens, shared between the prompt and the response.

What do I need to try GLM 5.3 Flash?

Create an account and add credit; the model is then available both in the browser chat and over the API. There is no contract or minimum spend.

Back to Models

z-ai/glm-5-3-flash

GLM 5.3 Flash

GLM-5.3-Flash is a native multimodal model from Z.ai. It is suited for efficient coding and long-horizon agent tasks. Its hybrid sparse and linear attention architecture maintains accurate long-context behavior while...

8/26/2026

1,310,720 tokens

Input: ¥13.1938/M

Output: ¥43.9793/M

Try in Chat Get API Key

Specifications

Modalities

Input

text

image

video

Output

text

Supported Parameters

frequency_penalty

include_reasoning

logit_bias

logprobs

max_tokens

min_p

presence_penalty

reasoning

reasoning_effort

repetition_penalty

response_format

seed

stop

structured_outputs

temperature

tool_choice

tools

top_k

top_logprobs

top_p

Max Output Tokens

131,072

Code Examples

curl https://api.fastmetal.ai/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "glm-5.3-flash",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

How GLM 5.3 Flash actually answers

Real responses to our standard prompts, recorded on FastMetal.

Count the number of 'r's in 'strawberry'

Count the number of 'r's in 'strawberry'. Explain your reasoning step by step.

# Counting 'r's in 'strawberry' **Step 1: Write out the word letter by letter** s - t - r - a - w - b - e - r - r - y **Step 2: Check each letter one at a time** | Position | Letter | Is it 'r'? | |----------|--------|-----------| | 1 | s | No | | 2 | t | No | | 3 | r | **Yes! (1)** | | 4 | a | No | | 5 | w | No | | 6 | b | No | | 7 | e | No | | 8 | r | **Yes! (2)** | | 9 | r | **Yes! (3)** | | 10 | y | No | **Step 3: Add up the matches** The 'r's appear at positions 3, 8, and 9. ## Answer: There are **3** 'r's in "strawberry" 🍓

7.2s response449 output tokens

Debug This Error

I'm getting the following error in my Node.js application: TypeError: Cannot read properties of undefined (reading 'map') at UserList (/app/components/UserList.js:12:25) at renderWithHooks (/app/node_modules/rea…

## What's happening The error means the `users` prop is `undefined` at the time `UserList` renders. Since you can't call `.map()` on `undefined`, JavaScript throws the TypeError. This usually happens for one of these reasons: 1. **The parent isn't passing the prop** — rendering `<UserList />` without `users`, or with a typo'd prop name like `user={users}`. 2. **Data hasn't loaded yet** — the parent fetches data asynchronously and its state starts as `undefined`: ```jsx const [users, setUsers] = useState(); // undefined until fetch resolves! return <UserList users={users} />; ``` 3. **API response shape mismatch** — the array is nested, e.g., you need `response.data.users` inst…

31.3s response1639 output tokens

Code Review

Please review the following Python function and suggest improvements for readability, performance, and best practices: def get_data(url, retries=3): import requests import time for i in range(retries):…

Solid foundation — you're already passing an explicit `timeout` and implementing retries, which many people skip. Here's a breakdown by category: ## Correctness & robustness (most important) - **Bare `except:`** catches *everything*, including `KeyboardInterrupt` and `SystemExit`, and silently discards the error. Catch specific exceptions: `requests.RequestException` for network issues, `ValueError` for invalid JSON. - **Retrying non-retryable failures**: a 401/403/404 will never succeed on retry, so you're sleeping 6 seconds for nothing. Only retry transient errors (5xx, 429, timeouts/connection errors). - **`item["active"]` raises `KeyError`** on malformed data. Use `item.get("active")`…

116.1s response6185 output tokens

Compare these answers side by side with other models →

Frequently asked questions

How much does the GLM 5.3 Flash API cost?: On FastMetal, GLM 5.3 Flash is billed per token in yen: ¥13.19 per 1M input tokens and ¥43.98 per 1M output tokens, before tax. Usage is drawn from a prepaid balance; there is no subscription or monthly fee.
Can I call GLM 5.3 Flash with the OpenAI SDK?: Yes. Point base_url at https://api.fastmetal.ai/v1 and pass "glm-5.3-flash" as the model; existing OpenAI-style code works unchanged, including streaming, tool calls and structured output.
What is the context window of GLM 5.3 Flash?: 1,310,720 tokens, shared between the prompt and the response.
What do I need to try GLM 5.3 Flash?: Create an account and add credit; the model is then available both in the browser chat and over the API. There is no contract or minimum spend.