Changes from 1.0
- Weights: quantized from Xor 26B-A4B 1.1 (revision
28ca09c7b76648b24d3561c940d1a7460d12fb8e, tag v1.1) instead of 1.0. The weights are new; nothing is shared with the 1.0 checkpoint.
- Quantization: NVIDIA Model Optimizer's
nvfp4_experts_only format with its own activation calibration, instead of reusing the activation scales of NVIDIA's nvidia/Gemma-4-26B-A4B-NVFP4 checkpoint. The KV cache is not quantized, so --kv-cache-dtype bf16 is no longer needed.
- Interface: requests can carry images or a video. Choice questions are scored in two option orders, and the calibration temperatures changed (see Interface).
- Serving: the bundle starts one single-GPU replica per Compose project.
Revisions
Table with columns: Revision, Release| Revision | Release |
|---|
main | Latest stable release (currently Xor 26B-A4B NVFP4 1.1) |
v1.1 | Xor 26B-A4B NVFP4 1.1 (xor-26b-a4b-nvfp4-1.1), released 2026-10-14, immutable |
v1 | Xor 26B-A4B NVFP4 1.0 (xor-26b-a4b-nvfp4-1.0), released 2026-10-01, immutable |
Pin a revision for reproducible results:
hf download juspay/Xor-26B-A4B-NVFP4 --revision v1.1 --local-dir xor-26b-a4b-nvfp4-1.1
Composition
Gemma 4 mixture-of-experts architecture: 30 layers, 128 routed experts per layer, 8 active per token.
Table with columns: Part, Precision| Part | Precision |
|---|
| Routed experts of all 30 layers | NVFP4 W4A4: FP4 (E2M1) weights in groups of 16 with FP8 (E4M3) group scales and an FP32 tensor scale; activations quantized to NVFP4 at run time |
| Attention, dense MLP, routers, embeddings and output, norms, vision tower | BF16, unquantized |
| KV cache | BF16 |
Quantized with NVIDIA Model Optimizer 0.46.1 (commit b5c76a00fc125eeebda0e2b43ecaf8229d16b9f0), format nvfp4_experts_only, Hugging Face export. Activation scales were calibrated on 64 samples from the train split of abisee/cnn_dailymail 3.0.0 (revision 96df5e686bee6baa90b8bee7c28b81fa3fa6223de), at sequence length 512 and batch size 1. QUANTIZATION.json records these settings and hf_quant_config.json lists the excluded modules.
Interface
Same request format as Xor 26B-A4B 1.1:
noul: binary probability
choice: categorical decision and full probability distribution (2 to 255 candidates)
score: expected ordinal score and full probability distribution (2 to 10 levels)
Each question is scored as an independent prompt in the model's chat template (thinking disabled), and the answer distribution is a softmax over the option-label logprobs at Answer: (. Temperatures are 2.0 for choice, 1.7 for noul and 1.0 for score. Each choice question is also scored with its options reversed, and the two probability distributions are averaged before the temperature is applied. confidence is the largest option probability. Every answer also returns x_lp, the raw label logprobs in option order.
Context is 131,072 tokens; a request whose prompt exceeds it is refused with 422, as is a request body over 8 MB.
A request may include images (1 to 8 base64 image data URLs) or video (one base64 video data URL; audio is not processed), but not both. Images passed limited smoke checks only; image and video quality have not been evaluated. PDF, audio, free-text generation and general chat are not supported.
Quick start
Download the release, verify and extract the serving bundle, and start one replica on one GPU:
hf download juspay/Xor-26B-A4B-NVFP4 --revision v1.1 --local-dir xor-26b-a4b-nvfp4-1.1 (cd xor-26b-a4b-nvfp4-1.1/serving && sha256sum -c xor-26b-a4b-nvfp4-1.1-serving.tar.gz.sha256) mkdir -p xor-26b-a4b-nvfp4-1.1-runtimetar -xzf xor-26b-a4b-nvfp4-1.1/serving/xor-26b-a4b-nvfp4-1.1-serving.tar.gz -C xor-26b-a4b-nvfp4-1.1-runtime export MODEL_DIR="$(cd xor-26b-a4b-nvfp4-1.1 && pwd)"export GPU_ID=0export API_PORT=8000export MODEL_ALIAS=xor-26b-a4b-nvfp4-1.1cd xor-26b-a4b-nvfp4-1.1-runtimebash ./run.sh
run.sh verifies every model file against checksums.sha256 and the bundle files against serving.sha256, then starts the stack and waits until it is healthy. The first start takes a few minutes. The API is then available at http://127.0.0.1:8000/v1/systemone:
curl -fsS http://127.0.0.1:8000/v1/systemone \ -H 'Content-Type: application/json' \ -d '{"model":"xor-26b-a4b-nvfp4-1.1","state":"The customer was charged twice.","questions":{"billing":{"type":"noul","instructions":"Is this a billing issue?"}}}'
{"model": "xor-26b-a4b-nvfp4-1.1", "answers": {"billing": {"type": "noul", "noul": 0.9793112926932397, "x_lp": [-6.5632, -0.0059]}}, "usage": {"input_tokens": 47, "output_tokens": 1}}
Probabilities can differ slightly between runs and deployments.
Stop the stack with bash ./stop.sh; the model files are kept. To run more replicas, start one stack per GPU with its own GPU_ID, API_PORT and COMPOSE_PROJECT_NAME.
The setup requires Linux x86-64, the Hugging Face CLI, Docker Engine with Docker Compose v2, the NVIDIA Container Toolkit, and an NVIDIA Blackwell GPU. It was validated on NVIDIA RTX PRO 6000 Blackwell (96 GB); other GPUs and memory sizes have not been tested.
Runtime
Both services use the pinned image prakhar1611/xor-sglang@sha256:94c48d2a6cc98dc456cf93f723707ea7dd81dddfe1061e823b348d68bbe8158f. The engine is started with:
python3 -m sglang.launch_server --model-path /model --trust-remote-code --tp-size 1 \ --context-length 131072 --max-prefill-tokens 131072 --chunked-prefill-size 16384 \ --mem-fraction-static 0.80 --moe-runner-backend flashinfer_cutlass --enable-metrics
--moe-runner-backend flashinfer_cutlass is required: SGLang's default MoE backend failed to start with this checkpoint.
Evaluation
All results are self-run, not official rankings, and were produced with the released weights, SGLang image and temperatures.
Decision Index 0.3
Decision Index 0.3, commit f8552a13b643d39f61185f5951bb5fed16bedf51, upstream runners and scorer unchanged, run on 2026-10-13. Hardware: 4 x NVIDIA RTX PRO 6000 Blackwell (96 GB), four independent single-GPU replicas with 8 concurrent requests each (32 in total). 140,620 requests completed with no errors; 140,178 were scored after 442 official exclusions.
Table with columns: Metric, Xor 26B-A4B 1.1 (BF16), Xor 26B-A4B NVFP4 1.1| Metric | Xor 26B-A4B 1.1 (BF16) | Xor 26B-A4B NVFP4 1.1 |
|---|
| Decision Index | 57.62 | 57.02 |
| Raw index | 67.88 | 67.48 |
| Breadth score | 56.89 | 56.23 |
Table with columns: Area (NVFP4 1.1), Benchmarks, Skill, Raw| Area (NVFP4 1.1) | Benchmarks | Skill | Raw |
|---|
| Knowledge & Reasoning | 11 | 42.32 | 55.34 |
| Language Understanding | 9 | 59.41 | 70.80 |
| Retrieval & Classification | 6 | 64.75 | 73.84 |
| Tools & Automation | 5 | 69.41 | 72.95 |
The BF16 reference ran on six NVIDIA B300 replicas at 24 concurrent requests, so this comparison does not separate the effect of quantization from differences in hardware and batching. This is the public self-run score, not the private Full score. evaluation/ contains the aggregate reports (index.json, scores.json, benchmark-summary.json); per-request inputs and responses are not included.
Latency under that load, per HTTP request: median 181.8 ms, mean 573.8 ms, p95 2,156.4 ms. These are loaded figures, not single-request latency, and they are not comparable with the B300 reference.
Public JEVBench self-run
On the public JEVBench tiers, NVFP4 1.1 answered 199 to 201 of 231 items correctly across runs; the BF16 build answered 204 in a matched run. Answers vary slightly between NVFP4 runs.
Operational notes
- Model files occupy 18.8 GB. This is not the GPU memory needed: the KV cache and engine take the rest of the
--mem-fraction-static 0.80 budget.
- The API binds to
127.0.0.1 and has no authentication. Remote deployments must add authentication, TLS, rate limits and request-size limits in front of it.
- The Compose restart policy is
unless-stopped. Docker does not restart an engine that is running but unhealthy, so external health monitoring is still needed.
GET /metrics on the API port returns the SGLang engine's Prometheus metrics. The proxy and the engine's --enable-metrics flag were added after the benchmarks and do not change the inference path; RELEASE_MANIFEST.json records the hashes of both the benchmarked and the released wrapper.
checksums.sha256 covers every model, serving and evaluation file except this card. RELEASE_MANIFEST.json records the source revision, runtime image, wrapper hashes, temperatures and benchmark settings.
Known limitations
- The data mix used to train Xor 26B-A4B 1.1 is not documented here, and no claim is made that its training data excludes the benchmarks above.
- The quantization build script is not published;
QUANTIZATION.json records its settings.
- Image and video quality have not been evaluated.
- Hardware other than RTX PRO 6000 Blackwell, and tensor parallelism above 1, have not been tested.
License
Apache License 2.0. Derived from Gemma 4 26B-A4B-it (Apache 2.0) and Xor 26B-A4B (Apache 2.0). See THIRD_PARTY_NOTICES.md.