TensorZero vs vLLM Semantic Router
TensorZero
tensorzero.comvLLM Semantic Router
vllm-sr.aiSide by side
| Figure | TensorZero | vLLM Semantic Router |
|---|---|---|
| Price from | Free | — |
| Free plan | Yes | — |
| Free trial | — | — |
| Open source | — | — |
| Web | Yes | — |
| macOS | — | Yes |
| Linux | Yes | Yes |
| API | Yes | Yes |
| Self-hosted | Yes | Yes |
| Plans published | 1 | 0 |
| Spec score · LLM gateways | 8.6 (#7) | 7.3 (#26) |
| Spec score · LLM Gateway Software | 8.0 (#13) | 7.2 (#31) |
| Product | TensorZero is an open-source platform that combines an LLM gateway, observability, evaluation, optimization, and experimentation. | vLLM Semantic Router describes itself as an open, programmable decision layer for models and compute. |
| Support | The project README directs users to Slack or Discord and offers work teams a Slack or Teams channel by email. | The site links to GitHub Discussions as a community resource. |
Plans
In their own words
TensorZero
TensorZero is a free, open-source stack that brings together an LLM gateway, observability, optimization, evaluation, and experimentation. Its gateway provides a unified API for model providers and supports routing, retries, fallbacks, prompt templates, schemas, multi-step workflows, and traffic routing for A/B tests. Documented integrations include Anthropic, AWS Bedrock, Azure, Google, OpenAI, OpenRouter, Together AI, vLLM, xAI, and OpenAI-compatible endpoints. Inference and feedback data go to the database you configure, where they can be queried with SQL; feedback can be tied to individual inferences or episodes. The gateway and UI can run through Docker, Docker Compose, Kubernetes and Helm, or a source build. API key authentication is available for gateway endpoints other than status and health checks. The project is available on GitHub, but is no longer maintained; its repository is archived and read-only. TensorZero is self-hosted and licensed under Apache 2.0. It collects pseudonymous aggregate usage analytics, excluding application data and inference inputs and outputs, with an option to disable collection.
vLLM Semantic Router
vLLM Semantic Router has no write-up on Specifiction yet; its figures are above.