# ERNIE 4.5 21B A3B Thinking: AI model fact sheet

- **Provider:** baidu
- **Released:** 2025-10-09
- **Context window:** 131,072 tokens
- **API pricing:** $0.07 / 1M input, $0.28 / 1M output
- **OpenRouter ID:** baidu/ernie-4.5-21b-a3b-thinking
- **Capabilities:** conversation, reasoning, analysis, code-generation

Baidu's lightweight reasoning MoE model (21B total, 3B active per token) refined for deep multi-step reasoning across logic, math, science, and code. 128K context, Apache-2.0.

Source: real side-by-side outputs, pricing and specs at https://rival.tips/models/ernie-4.5-21b-a3b-thinking