# Aion 3.5

> Aion 3.5 is a language model from Aion Labs, released on 23 Sept 2026. It accepts text and generates text, with a 262K-token context window and up to 33K output tokens per response. As of 4 Oct 2026, the lowest listed API price is $3 per million input tokens and $6 per million output tokens (OpenRouter), across 1 provider we track.

Source page: https://www.aimodel.directory/models/aion-3-5
Last verified: 4 Oct 2026

## Specifications

- **Developer:** Aion Labs
- **Release date:** 23 Sept 2026 (source: OpenRouter, https://openrouter.ai/aion-labs/aion-3.5)
- **Status:** Generally available
- **Context window:** 262K (262,144 tokens) (source: OpenRouter, https://openrouter.ai/aion-labs/aion-3.5)
- **Max output:** 33K tokens (source: OpenRouter, https://openrouter.ai/aion-labs/aion-3.5)
- **Input:** Text (source: OpenRouter, https://openrouter.ai/aion-labs/aion-3.5)
- **Output:** Text (source: OpenRouter, https://openrouter.ai/aion-labs/aion-3.5)
- **Reasoning mode:** Yes (source: OpenRouter, https://openrouter.ai/aion-labs/aion-3.5)
- **Tool calling:** Yes (source: OpenRouter, https://openrouter.ai/aion-labs/aion-3.5)
- **Structured output:** No (source: OpenRouter, https://openrouter.ai/aion-labs/aion-3.5)

## API pricing (USD per 1M tokens)

| Provider | Input | Output | Cached input | Context |
|---|---|---|---|---|
| OpenRouter | $3 | $6 | $0.75 | 262K |

## FAQ

### What is the context window of Aion 3.5?

Aion 3.5 has a context window of 262,144 tokens (262K) and can generate up to 32,768 tokens in a single response, according to OpenRouter.

### How much does the Aion 3.5 API cost?

Aion 3.5 is listed from $3 per million input tokens and $6 per million output tokens (OpenRouter). Prices last verified 4 Oct 2026.

### When was Aion 3.5 released?

Aion Labs released Aion 3.5 on 23 Sept 2026, according to OpenRouter.

---
Data licensed CC BY 4.0. Cite as: AI Model Directory, "Aion 3.5", https://www.aimodel.directory/models/aion-3-5