Kimi K3-256K API
About
Build advanced reasoning agents with Kimi K3-256K, a specialized AI model optimized for complex logic and chain-of-thought tasks. This model delivers available completely free of charge, native tool calling support, open weights architecture. Access Kimi K3-256K via the Kimi For Coding (kimi.com) API with up to 131K output tokens.
Capabilities
Input Modalities
textimage
Output Modalities
text
Reasoning
Yes
Structured Output
Limits
Context Window
262K
Tokens
Input Limit
262K
Tokens
Max Output
131K
Tokens
Pricing
Standard (per 1M tokens)
Input
Free
Output
Free
Caching (per 1M tokens)
Read
Free
Write
Free
Frequently Asked Questions
Kimi K3-256K by Kimi For Coding (kimi.com) costs Free per 1M input tokens and Free per 1M output tokens. Cached reads cost Free per 1M tokens. Cache writes cost Free per 1M tokens.
Model Details
ID
k3-256k
Provider
Kimi For Coding (kimi.com)Family
kimi-k3
Release Date
Jul 16, 2026
Knowledge Cutoff
N/A
API Integration
NPM Package
@ai-sdk/openai-compatible
Environment Variables
KIMI_API_KEY
API Base URL
https://api.kimi.com/coding/v1