TensorZero
Open-source LLM infrastructure for gateway, observability, optimization, and experimentation
Founded
N/A
Starting Price
Free
Category
Developer Tools
Last updated March 14, 2026
About TensorZero
TensorZero is an open-source LLMOps platform that unifies an LLM gateway, observability, optimization, evaluations, and experimentation into a single stack. Written in Rust for extreme performance (<1ms P99 latency overhead at 10,000 QPS), TensorZero provides a unified API for every major LLM provider including OpenAI, Anthropic, Google, AWS Bedrock, Azure, Mistral, and many more. The platform creates a feedback loop for optimizing LLM applications — turning production data into smarter, faster, and cheaper models through prompt optimization, fine-tuning, reinforcement learning, and distillation. TensorZero Autopilot acts as an automated AI engineer that analyzes observability data, optimizes prompts, sets up evaluations, and runs A/B tests. Backed by $7.3M in seed funding and 11K+ GitHub stars, TensorZero is used by companies from frontier AI startups to the Fortune 50.
Pros & Cons
Pros
- Fully open source (Apache 2.0) and 100% self-hosted — no vendor lock-in
- Extremely fast Rust-based gateway with sub-millisecond latency overhead
- Comprehensive LLMOps platform: gateway + observability + optimization in one stack
- Supports every major LLM provider through unified API
- Unique optimization loop: production feedback drives prompt and model improvements
Key Features
Unified LLM gateway with <1ms P99 latency (written in Rust)
Supports all major LLM providers through a single API
Built-in observability with structured inference traces
A/B testing and traffic routing between model variants
Prompt optimization, fine-tuning, and model distillation
LLM-as-judge evaluations and heuristic benchmarks
Multi-step workflow support with episode-level feedback
ClickHouse-backed analytics for real-time monitoring
TensorZero Autopilot: automated AI engineer for optimization
Production LLM application optimization
Pricing
TensorZero Stack
Free
- 100% self-hosted and open source (Apache 2.0)
- LLM gateway with <1ms P99 latency
- Built-in observability with ClickHouse
- Prompt and model optimization
- A/B testing and experimentation