Aion-3.5 API

aion-labs/aion-3.5
Aion 3.5 is a multi-model roleplaying and storytelling system from AionLabs that uses collaborative generation to produce stronger narrative structure, tension, and conflict.
Context
256K tokens
Input
$4.1262 / 1M tokens
Output
$8.2524 / 1M tokens
Released
Sep 23, 2026

How to use Aion-3.5 API

Install any OpenAI-compatible SDK, point it at api.aimlapi.com/v1, and set the model to aion-labs/aion-3.5.
import requests

r = requests.post(
    "https://api.aimlapi.com/v1/chat/completions",
    headers={"Authorization": "Bearer " + AIMLAPI_KEY},
    json={
      "model": "aion-labs/aion-3.5",
      "messages": [
        {
          "role": "user",
          "content": "Hello!"
        }
      ]
    },
)
print(r.json())
const r = await fetch("https://api.aimlapi.com/v1/chat/completions", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.AIMLAPI_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "model": "aion-labs/aion-3.5",
    "messages": [
      {
        "role": "user",
        "content": "Hello!"
      }
    ]
  }),
});
console.log(await r.json());
curl -X POST https://api.aimlapi.com/v1/chat/completions \
  -H "Authorization: Bearer $AIMLAPI_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"aion-labs/aion-3.5","messages":[{"role":"user","content":"Hello!"}]}'

OpenAI-compatible — swap the base URL and it works with your existing SDK.

Aion-3.5 API Pricing

TypePrice
Input
$4.1262 / 1M tokens
Output
$8.2524 / 1M tokens
Cached input
$1.03155 / 1M tokens

A documented caveat is that Aion Labs offers a free tier with request and token limits, including 15 requests per minute and 20,000 tokens per minute/day on the free tier.

Frequently asked questions

Aion-3.5 is a multi-model roleplaying and storytelling system from AionLabs built on the GLM family of models.

It uses a collaborative generation process where multiple specialized models each contribute to a response. This is intended to produce stronger narrative structure and more compelling tension and conflict.

It is optimized for roleplaying and storytelling tasks. The model is focused on narrative quality rather than general-purpose chat alone.

Aion-3.5 is a multi-model system. Multiple specialized models work together during generation.

Aion-3.5 is built on the GLM family of models.

Yes, the model supports tools. It can work with function-style tool use.

Yes, structured output is supported for this model.

Yes, streaming is supported.

Yes, parallel tool calls are supported.

Yes, file input and web search are supported.

Start building with Aion-3.5

Get API Key
1000+ models, one API.