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This reference covers the full Truss config.yaml schema for BIS-LLM (Baseten Inference Stack v2). The v2 stack simplifies the build: section and moves runtime fields out of build. For translating an Engine-Builder-LLM (v1) configuration to BIS-LLM, see Migrate from Engine-Builder-LLM.

Configuration structure

Build configuration

The build section configures model compilation and optimization settings.
checkpoint_repository
object
required
Specifies where to find the model checkpoint. Same structure as v1 with v2-specific optimizations.For training checkpoint deployment, see Deploy with optimized inference engines. For cloud storage sources (GCS, S3, Azure), see Deploy from cloud storage.
quantization_type
string
Quantization format for model weights (simplified from v1).Options:
  • no_quant: precision of the repo (fp16 or bf16). BIS-LLM also supports quantized checkpoints from nvidia-modelopt libraries.
  • fp8: FP8 weights + 16-bit KV cache
  • fp8_kv: FP8 weights + FP8 KV cache
  • fp4: FP4 weights + 16-bit KV cache (B200 only)
  • fp4_kv: FP4 weights + FP8 KV cache (B200 only)
  • fp4_mlp_only: FP4 MLP layers only + 16-bit KV cache (B200 only)
For detailed quantization guidance including hardware requirements, calibration strategies, and model-specific recommendations, see Quantization guide.
quantization_config
object
Configuration for post-training quantization calibration.
num_builder_gpus
number
Number of GPUs to use during the build process. Auto-detected from resources when unset. Minimum: 1, with no fixed maximum.
skip_build_result
boolean
default:"false"
Skip the engine build step and use a pre-built model that does not require quantization. Use when you have a pre-built engine from model cache.

Runtime configuration

The runtime section configures inference engine behavior.
max_seq_len
number
default:"auto-detected from model config"
Maximum sequence length (context) for single requests. Range: 1 to 1048576.
max_batch_size
number
default:"256"
Maximum number of input sequences processed concurrently. Range: 1 to 2048.
max_num_tokens
number
default:"8192"
Maximum number of batched input tokens after padding removal. Range: 65 to 131072.
tensor_parallel_size
number
default:"1"
Number of GPUs to use for tensor parallelism. Auto-detected from resources. Minimum: 1, with no fixed maximum (set it to the number of GPUs in your accelerator setting).
enable_chunked_prefill
boolean
default:"true"
Enable chunked prefilling for long sequences.
served_model_name
string
default:"model name from config"
Model name returned in API responses.
patch_kwargs
object
Preview. Pass-through configuration patches for the v2 inference stack. Fields under patch_kwargs may change without notice; keys that overlap standard runtime fields (or build_config) are logged as errors at deploy time — set those through the standard runtime: fields instead.

Complete configuration examples

Qwen3-30B-A3B-Instruct-2507 MoE with FP4 on B200

GPT-OSS 120B on B200:1 with no_quant

This example deploys GPT-OSS with default settings. For production throughput with Eagle speculative decoding on B200, see Speculative decoding for BIS-LLM and Advanced features for BIS-LLM.

DeepSeek V3

This example deploys a pre-quantized ModelOpt checkpoint with no_quant. For higher throughput on DeepSeek V3 family models, use multi-GPU B200 layouts with MTP speculative decoding or disaggregated serving. See Speculative decoding for BIS-LLM and Disaggregated serving.

Hardware selection

GPU recommendations for v2:
  • B200: Best for FP4 quantization and next-gen performance
  • H100: Best for FP8 quantization and production workloads
  • Multi-GPU: Required for large MoE models (>30B parameters)
Configuration guidelines: