What it is
A fixed-decay recurrent core.
Nothing more complicated than that.
FWKV (Feed-forward Weighted Key Value) is a small recurrent language model architecture proposed in May 2026 by FlameF0X. It began as a side project inspired by RWKV, then turned into something faster than any dense or MoE Transformer of similar size on ordinary CPUs.
The recurrence is a single accumulated state with a learned, constant per-channel decay — computed by a standard parallel scan. No pairwise time-mixing, no data-dependent gates, no custom CUDA kernels. The ROSA variant adds an exact, training-free suffix-automaton copy signal so the model can reuse long-range patterns without attention.
It is still early and unstable. Use it if you care about simplicity and CPU speed; skip it if you need a production chat model tomorrow.
Why it exists
Speed from constraints, not from kernels.
- Decay Fixed per-channel W. The decay is learned once and constant at inference. That single choice lets the whole history collapse into a vectorized Hillis-Steele scan.
- ROSA Exact causal copy. A suffix automaton answers “what followed this longest prior match?” and injects the answer as an embedding. No attention, no parameters for the predictor itself.
- Size Factorized embeddings. Vocab projects through a 128-d bottleneck instead of a full d_model matrix. Fewer parameters, cheaper logits, still tied input/output weights.
- Honest It is not ready for everything. At 50–56M parameters the model confabulates freely. The point of the release is the architecture and the measured CPU throughput, not a claim of intelligence.
Models
Named simply so you can find them.
Pattern: FWKV-[size or type].
Everything lives under the
FWKV organization on Hugging Face.
Language models
- FWKV-ROSA ~56M · UltraChat · live
- FWKV-50M 50.6M · WikiText · live
- FWKV-29M 28.9M · WikiText · live
- FWKV-TinyStories TinyStories · live
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FWKV-100M planned · 2026–2027
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FWKV-Translation planned · late 2026
Vision
- FWKV-Vision image · live
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FWKV-CLIP image · NAP
Other modalities
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FWKV-Bert NAP
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Text-to-speech NAP
Paper
FWKV: Simplicity Is All You Need for Efficient Language Modeling