# Aion 3.5

> Aion 3.5 is a reasoning model from Aion Labs built on the GLM family of models. Several specialized models contribute to each response, which gives stronger narrative structure, tension and conflict and a more nuanced treatment of mature and darker themes, so it suits fiction writing. 262,144-token context.

**ID**: `aion-labs/aion-3.5`  
**Creator**: aion-labs  
**Category**: text  
**Context**: 262K tokens  
**Pricing**: $3.00 / $6.00 per 1M · billed by your provider (BYOK)  
**Released**: 2026-09-23  
**Web page**: https://anyrouter.dev/model/aion-labs/aion-3.5

**Input modalities**: text  
**Output modalities**: text  

**Capabilities**: chat, streaming, reasoning, function-calling

## Usage

**Endpoint**: `POST https://anyrouter.dev/api/v1/chat/completions`

```bash
curl https://anyrouter.dev/api/v1/chat/completions \
  -H "Authorization: Bearer $ANYROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "aion-labs/aion-3.5",
  "messages": [
    {
      "role": "user",
      "content": "Say hi in 3 words."
    }
  ]
}'
```

## Providers

| Provider | Input | Output |
| --- | --- | --- |
| aion-labs-byok | $3.00/M (list) | $6.00/M (list) |
| nousresearch-byok | $3.00/M (list) | $6.00/M (list) |
| infron-byok | $3.00/M (list) | $6.00/M (list) |
| aimlapi-byok | $3.17/M (list) | $6.35/M (list) |
| openrouter-byok | $3.00/M (list) | $6.00/M (list) |

BYOK routes are billed by your own provider key — AnyRouter charges $0. Rates marked (list) are the provider's published list price.

## Model card


### Strengths [1]

- Several specialized models contribute to each response (vendor-stated).
- Stronger narrative structure, tension and conflict in stories (vendor-stated).

### Use cases [1]

- Fiction writing

### API notes [1]

- Supports tool calls.
- Reasoning effort levels low, high and max (default high).

### Links

- docs: https://aionlabs.ai/docs/

### Sources

1. [Aion Labs model list](https://api.aionlabs.ai/v1/models) (accessed 2026-11-02)
2. [Aion Labs](https://aionlabs.ai) (accessed 2026-11-02)

## Source

- Upstream docs: https://api.aionlabs.ai/v1/models