kandiga 0.7.0

Run 35B-397B MoE models in 2-8GB RAM. Custom Metal GPU kernels. Any Mac.

Kandiga

Giant models. Tiny memory.

Kandiga is an open-source MoE inference engine for Apple Silicon. Run models that normally need 20-224GB of RAM in 2-8GB — on any Mac. No cloud, no API keys.

Supported Models

Model	Parameters	Active	Disk	Kandiga RAM	Min. Mac	Decode	TTFT
Qwen3.5-35B-A3B	35B	3B	20 GB	~2 GB	8 GB	6.5 tok/s	3-8s
Qwen3.5-122B-A10B	122B	10B	70 GB	~4 GB	16 GB	1.4 tok/s	7-27s
Qwen3.5-397B-A17B	397B	17B	224 GB	~8 GB	24 GB	~1 tok/s	TBD

Without Kandiga, these models require their full disk size in RAM. With SEM, only the shared layers load to memory — expert weights stay on disk and are read on demand.

How it works

MoE models have hundreds of expert sub-networks per layer, but only activate a few per token. Kandiga exploits this sparsity with six techniques:

1. Selective Expert Materialization (SEM) — shared layers load to GPU, expert weights stay on disk. Only the 8 router-selected experts are read per token per layer.

2. Custom Metal GPU kernels — during prefill (processing your prompt), expert MLP runs entirely on GPU via custom Metal shaders. One dispatch handles ALL experts for ALL tokens — zero Python loop overhead.

3. CPU NEON decode — during generation (single token), expert MLP runs on CPU with NEON-vectorized 4-bit dequant. Faster than GPU for single-token due to zero Metal dispatch overhead.

4. Cross-layer expert speculation — predicts next layer's expert routing with 77% accuracy. Pre-fetches predicted experts into OS page cache during current layer's compute. Overlaps I/O with computation.

5. TurboQuant KV compression — compresses the KV cache from 16-bit to 3-bit (3.8x) using PolarQuant + QJL error correction. Enables longer conversations without running out of memory.

6. ZMLX fused kernels — third-party Metal kernel optimizations for attention and norms. +45% decode speed.

Install

pip install kandiga

# For maximum speed (includes ZMLX fused kernels):
pip install kandiga[fast]

Requirements: macOS with Apple Silicon (M1/M2/M3/M4), Python 3.10+

Quick start

# One-time setup: choose model, download, prepare expert files
kandiga setup

# Interactive chat
kandiga chat

# Fast mode (K=4 experts instead of 8, ~2x speed)
kandiga chat --fast

# One-shot prompt
kandiga "What is the capital of France?"

# Start an OpenAI-compatible API server
kandiga serve

# Run benchmarks
kandiga bench

# Update to latest version
kandiga update

# View changelog
kandiga changelog

Performance

Measured on M4 Mac Mini (16GB):

Model	Mode	Decode	TTFT (first turn)	TTFT (follow-up)	RAM
Qwen3.5-35B	K=8	3.7 tok/s	5-15s	3-4s	~2 GB
Qwen3.5-35B	K=4	6.5 tok/s	3-8s	3-4s	~2 GB
Qwen3.5-122B	K=4	1.4 tok/s	7-27s	3-4s	~4 GB

Key: follow-up TTFT is constant (3-4s) regardless of conversation length thanks to persistent KV cache.

Persistent KV Cache (Conversation Memory)

The biggest problem with local LLMs: every message re-processes the ENTIRE conversation history. Turn 30 re-reads turns 1-29 — even though the model already read them.

Kandiga solves this with persistent KV cache:

Without persistent cache:
  Turn 1:  8s    (reads invoice)
  Turn 5:  25s   (re-reads invoice + 4 turns)
  Turn 30: 2min+ (re-reads everything)

With persistent cache:
  Turn 1:  8s    (reads invoice once)
  Turn 2:  3s    (only reads new question)
  Turn 5:  3s    (only reads new question)
  Turn 30: 3s    (only reads new question)

The model reads the conversation once and keeps its understanding in memory. Every follow-up only processes the new message. TTFT stays flat at 3-4 seconds regardless of conversation length.

from kandiga.engine import KandigaEngine

engine = KandigaEngine()
engine.load()
engine.start_session()

# Turn 1: send a document (8s TTFT — processes the document)
for token in engine.session_generate("Here is an invoice: ..."):
    print(token, end="")

# Turn 2: follow-up (3s TTFT — document already cached)
for token in engine.session_generate("What is the most expensive item?"):
    print(token, end="")

# Turn 30: still 3s TTFT
for token in engine.session_generate("Summarize everything"):
    print(token, end="")

engine.end_session()

Combined with TurboQuant (3.8x KV compression), conversations can run for 32K+ tokens before hitting memory limits.

GPU Metal Prefill

During prefill (processing your prompt), Kandiga uses custom Metal compute shaders instead of CPU:

• Phase 1: Gate + Up projection + SwiGLU activation — one Metal dispatch for ALL experts
• Phase 2: Down projection — one Metal dispatch

This eliminates the Python loop entirely. All expert computation for all tokens happens in two GPU dispatches per layer. Combined with C-level parallel pread via GCD, this gives 3-5x faster prefill compared to the CPU-only path.

Prefill improvement (35B, ~150 tokens):
  CPU baseline:     24.0s
  GPU + Python loop: 7.7s
  GPU Metal kernel:  6.1s  (current)

KV Cache Compression (TurboQuant)

Compresses the KV cache from 16-bit to 3-bit per element (3.8x reduction) with only 4% quality loss. Based on Google Research TurboQuant.

Context Length	Standard (float16)	Kandiga (3-bit)	Compression
4K tokens	16.8 MB	4.5 MB	3.8x
8K tokens	33.6 MB	8.9 MB	3.8x
16K tokens	67.1 MB	17.8 MB	3.8x
32K tokens	134 MB	35.3 MB	3.8x

Architecture

User prompt
    |
    v
[Tokenizer + Chat Template]
    |
    v
[MLX Forward Pass — per layer:]
    |
    +---> GPU: Attention + Norms + Router (MLX lazy eval)
    |
    +---> Prefill (multi-token):
    |     GPU Metal kernel: batch pread + dequant + matmul + SiLU
    |     (one dispatch for ALL experts, ALL tokens)
    |
    +---> Decode (single-token):
    |     CPU NEON: pread + 4-bit dequant matvec + GCD parallel
    |     (faster than GPU for single vectors)
    |
    +---> Cross-layer speculation: predict next layer's experts
    |     Background prefetch into OS page cache
    |
    v
[Token Output — streaming]

API Server

OpenAI-compatible HTTP API:

kandiga serve --port 8340

import openai

client = openai.OpenAI(base_url="http://localhost:8340/v1", api_key="unused")
response = client.chat.completions.create(
    model="mlx-community/Qwen3.5-35B-A3B-4bit",
    messages=[{"role": "user", "content": "Hello!"}],
    stream=True,
)
for chunk in response:
    print(chunk.choices[0].delta.content or "", end="")

Key Technical Details

• Expert binary format: packed 4-bit uint32 weights with bfloat16 scales/biases, 4096-byte header per layer file. Expert dimensions auto-detected from header.
• Two C libraries: libkandiga_cpu_expert.dylib (35B, hardcoded dims) and libkandiga_cpu_expert_lg.dylib (122B/397B, dynamic dims from header)
• Custom Metal shaders: attention.metal (19 kernels), expert_mlp.metal, moe_block.metal — compiled at runtime
• Cross-layer speculation: 77% prediction accuracy using router gate CPU matmul (~0.05ms)
• Layer skipping: large models skip routed experts on every 3rd layer (shared expert only). Reduces syncs by 33% with quality preserved.
• Thinking mode disabled: enable_thinking=False in chat template to avoid wasted tokens
• Auto-update checker: background check against PyPI, cached 24h

Development

git clone https://github.com/kantheon/kandiga.git
cd kandiga
pip install -e ".[serve,fast]"

# Build CPU expert libraries
cd kandiga/metal && make && cd ../..

# Run tests
pytest tests/ -v

License

MIT — Built by Kantheon