Step 5 Preview
600B open weights, trained for long-running agents
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Step 5 Preview is StepFun's open-weight MoE for coding, financial research and long-running agents. It has 600B total parameters, 27B active per token and a 1M-token context, with deployment support for vLLM, SGLang and Transformers.
PH · launched Oct 17, 2026 · 83 upvotes (top 2%) · 0 views
Niche: large language models · 191 launches, 4 in the last 7 days ▼ -33% · Explore this niche →
Category and tags
- Horizontal
- Model & infra
- Developer
- AI-native
- Commercial product
- Open Source
- Artificial Intelligence
Visit website ↗ Source listing ↗
More like this: all 191 launches in large language models →
Could you build this?
No Training a 600B-parameter MoE foundation model with a 1M context window requires tens of millions of dollars in compute, custom distributed training infra, and world-class AI research teams.
What it would actually take: Requires high-performance computing clusters (thousands of H100/H800 GPUs connected via InfiniBand), Megatron-LM/DeepSpeed-based 3D parallelism (tensor, pipeline, expert parallelism), bespoke data curation pipelines processing tens of trillions of tokens, and custom CUDA kernels for efficient sparse mixture-of-experts routing and extended context attention.
Competitors
Other products that read as similar to this one : 18 launches clear the similarity bar, closest 8 shown.
Attention rank: #2 of 19 (itself plus its competitors, highest first, normalized so YC and Product Hunt are compared fairly).
Launched 326 days after the earliest competitor.
- Naive-N0.5-Flash · github · 2026-09-27 · 142 upvotes · similarity 0.39
- Muse Spark Open · ph · 2026-10-16 · 85 upvotes · similarity 0.39
- OLMo-core 3 · ph · 2026-10-03 · 1 upvotes · similarity 0.38
- Step 3.7 Flash · ph · 2026-05-30 · 183 upvotes · similarity 0.36
- Hy4 preview · ph · 2026-08-29 · 215 upvotes · similarity 0.36
- OpenArb —Open-Weight Arbitrage Audit Kit · ph · 2026-10-06 · 1 upvotes · similarity 0.36
- Step-5-Preview · github · 2026-10-12 · 60 upvotes · similarity 0.35
- GPT-5.5 by OpenAI · ph · 2026-04-26 · 476 upvotes · similarity 0.35
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