Zen LM - Open Foundation Models for Agentic AI
95 open Zen models across Zen3, Zen4, and Zen5. Chat, code, vision, audio, image, embeddings, rerankers, and safety.
From edge-class Zen5 Nano (0.8B) to the Zen5 Max frontier MoE. 8K to 1M context windows. OpenAI- and Anthropic-compatible API. One key, one billing surface — the Zen API, resold natively.
Zen 5 - Next-Generation Agentic Models
Native agentic training, chain-of-thought reasoning, and Zen Embedding for retrieval.
Zen5 Chat Ladder
| Model | Parameters | Architecture | Context | Tier |
|---|---|---|---|---|
| Zen5 Nano 0.8B | 0.9B dense | Multimodal dense | 32K | Edge |
| Zen5 Nano 2B | 2B dense | Multimodal dense | 32K | Starter |
| Zen5 Nano 4B | 5B dense | Multimodal dense | 32K | Starter |
| Zen5 Nano 9B | 10B dense | Multimodal dense | 32K | Pro |
| Zen5 Flash | 4B dense | Zen dense | 32K | Starter |
| Zen5 Mini | 230B (10B active) | Zen agentic MoE | 192K | Pro |
| Zen5 DEFAULT | 35B (3B active) | Zen frontier MoE | 256K | Pro |
| Zen5 Coder | 80B sparse | Zen Coder MoE | 256K | Pro |
| Zen5 Pro | 284B (37B active) | Zen Flash MoE | 1M | Ultra |
| Zen5 Max FRONTIER | Full Zen Pro weights | Zen Pro MoE | 1M+ | Ultra Max |
Zen5 Embedding
| Model | Parameters | Dimensions | Context | Endpoint |
|---|---|---|---|---|
| Zen5 Embedding 0.6B | 0.6B | 1024 | 32K | /v1/embeddings |
| Zen5 Embedding 4B | 4B | 2560 | 32K | /v1/embeddings |
| Zen5 Embedding 8B | 8B | 4096 | 32K | /v1/embeddings |
Zen 4 - Production Chat & Code
The everyday Zen production family. MoE flagships, thinking models, and a dedicated coder line.
Zen4 Chat
| Model | Parameters | Architecture | Context | Tier |
|---|---|---|---|---|
| Zen4 Mini | Dense | Dense | 128K | Starter |
| Zen4 | 744B (40B active) | MoE | 202K | Ultra Max |
| Zen4 Pro | 80B (3B active) | MoE | 131K | Ultra |
| Zen4 Thinking | 80B (3B active) | MoE + CoT | 131K | Pro Max |
| Zen4 Ultra | 744B (40B active) | MoE + CoT | 262K | Ultra Max |
| Zen4.1 | Dense | Dense | 1M | Ultra |
| Zen4 Max FLAGSHIP | Dense | Dense | 1M | Ultra Max |
Zen4 Coder
| Model | Parameters | Architecture | Context | Tier |
|---|---|---|---|---|
| Zen4 Coder Flash | 30B (3B active) | MoE | 262K | Pro Max |
| Zen4 Coder | 480B (35B active) | MoE | 163K | Ultra |
| Zen4 Coder Pro | 480B | Dense BF16 | 131K | Ultra Max |
Zen 3 - Multimodal & Specialty
Vision, audio, web, safety, embeddings, image generation, and edge.
Zen3 Chat & Vision
| Model | Parameters | Modalities | Context | Tier |
|---|---|---|---|---|
| Zen3 Omni | ~200B dense | Text + Vision + Audio | 202K | Pro Max |
| Zen3 VL (default 30B-A3B) | 30B (3B active) | Vision + Language | 262K | Pro Max |
| Zen3 VL 2B / 8B / 32B | 2B / 9B / 33B | Vision + Language | 32K - 128K | Starter - Pro Max |
| Zen3 VL 235B-A22B FRONTIER VL | 235B (22B active) | Vision + Language (MoE) | 256K | Ultra Max |
| Zen3 Web 8B / 14B / 32B | 8B / 15B / 32B | Web agentic / browser | 32K | Starter - Pro Max |
| Zen3 Nano | 8B dense | Edge chat | 128K | Starter |
| Zen3 Guard | 4B dense | Safety classifier | 65K | Pro |
Zen3 Embedding & Reranker
| Model | Type | Parameters | Context | Endpoint |
|---|---|---|---|---|
| Zen3 Embedding (small / medium / default) | Text embedding | 0.6B / 4B / N/A | 8K - 40K | /v1/embeddings |
| Zen3 Reranker (small / medium / default) | Reranker | 0.6B / 4B / 8B | 40K | /v1/rerank |
| Zen3 VL Embedding 2B / 8B | Multimodal embedding | 2B / 8B | 32K | /v1/embeddings |
| Zen3 VL Reranker 2B / 8B | Multimodal reranker | 2B / 9B | 32K | /v1/rerank |
Zen3 Image, Audio & Speech
| Family | Models | Endpoint | Pricing |
|---|---|---|---|
| Zen3 Image | image, image-max, image-dev, image-fast, image-sdxl, image-playground, image-ssd, image-jp | /v1/images/generations | from $0.00013/step |
| Zen3 Audio (STT) | audio, audio-fast, asr, asr-0.6B, asr-aligner, asr-v1 | /v1/audio/transcriptions | from $0.002/min |
| Zen3 TTS | tts, tts-hd, tts-fast, tts-0.6B, tts-voice-design, tts-custom-voice | /v1/audio/speech | from $2/1M chars |
Why Zen
One API, Three Generations
Zen3, Zen4, and Zen5 share one OpenAI- and Anthropic-compatible API. Migrate generations without changing client code.
Frontier Agentic
Zen5 Mini hits 80.2% SWE-Bench Verified and 76.3% BrowseComp. Zen5 ladder is trained on 200K+ real-world environments via large-scale RL.
Edge to Frontier
From Zen5 Nano 0.8B (phone / browser WASM class) to Zen5 Max (1M+ context, Mac Studio Ultra class). Same family, same identity layer.
Full Modality Coverage
Chat, code, vision-language, web agentic, embeddings, rerankers, image generation, streaming ASR, and TTS - all under the Zen brand.
Long Context
Up to 1M tokens on Zen5 Pro and Zen5 Max. 256K standard on Zen5 default and Zen5 Coder. 8K-262K across the rest of the catalog.
Open Weights Where It Counts
Zen5 default is Apache-2.0. Zen5 Pro ships as 81 GB IQ2_XXS-imatrix GGUF on HuggingFace. Run frontier models on a single 128 GB box.
Zen Agentic Dataset
10B+ tokens of real-world tool use and multi-step reasoning
Tokens
Real agentic training data across the Zen5 ladder
Environments
Real-world environments used in large-scale RL
SWE-Bench Verified
Zen5 Mini on the SWE-Bench Verified benchmark
BrowseComp
Zen5 Mini on the BrowseComp web-agent benchmark