Free GLM 5.3 API: Use GLM 5.3 and GLM 5.3 Flash Without Paying

FreeTheAI serves two GLM models on its free tier. Both work through one key and one base URL, and both are listed with their current limits on the models page.

Both models list a very large context window and up to about 131K output tokens on their model pages. Use the full model ID, including the fta/zai/ prefix, in every request.

1. Create a free account at freetheai.org/signup with a Gmail, Outlook, Yahoo, or iCloud address and confirm your email.
2. Open Dashboard > API keys and create a key. It is shown once, so copy all of it.
3. Do today's check-in. Free models unlock until 00:00 UTC.
4. Send a request to the base URL below.

curl https://api.freetheai.org/v1/chat/completions \
  -H "Authorization: Bearer ftai_your_key_here" \
  -H "Content-Type: application/json" \
  -d '{"model": "fta/zai/glm-5.3", "messages": [{"role": "user", "content": "Say hello in five words."}]}'

In an app, the base URL is https://api.freetheai.org/v1. Apps that ask for the full address (JanitorAI, for example) need https://api.freetheai.org/v1/chat/completions.

GLM 5.3 reasons before it answers unless you ask it not to. Thinking helps with code and hard questions, but it makes replies slower and uses more tokens. To turn it off for a request, send either of these fields:

{
  "model": "fta/zai/glm-5.3",
  "thinking": { "type": "disabled" },
  "messages": [{ "role": "user", "content": "Summarize this in one line." }]
}

Or use the OpenAI-style switch "reasoning_effort": "none". Leave both out to keep the model's default. The reasoning, when there is some, arrives in reasoning_content, separate from the reply text.

GLM 5.3 reads text only. A request that includes a picture gets a clear 400 error that says the model accepts text only. Send pictures to fta/zai/glm-5.3-flash instead, as standard OpenAI image_url content parts (a data URL or an https link).

• Roleplay apps: JanitorAI, SillyTavern, Chub AI, and RisuAI all work with fta/zai/glm-5.3.
• Coding agents: Claude Code, Cline, OpenCode, and Kilo Code. Tool calls work.
• Chat apps: Open WebUI, LibreChat, Chatbox, and more in the setup guides.