TensorZero
Do not start a new project on this. The repo was archived read-only on 12/06/2026 and the company wound down with half its $7.3M seed unspent — the code is still Apache-2.0 and still runs, but the last release is 2026.6.0 and nobody is patching providers. The optimization loop it built is the best in this category and now has no maintained equivalent.
PRICING
| Open source | Free | Apache-2.0, self-hosted; archived read-only 12/06/2026, last release 2026.6.0 (04/06/2026) |
There is no vendor to pay and no vendor to call. Anything you run is a fork you maintain.
checked 2026-09-03 · vendor pricing page
Element scores
Strengths
The design is still the sharpest statement of what an LLMOps platform should be: one Rust gateway with sub-millisecond p99 overhead in front of 19 providers, inferences and feedback stored in your own ClickHouse, evaluations with heuristics and LLM judges, A/B experimentation with bandits, and an optimization layer that turns those production traces back into better prompts and fine-tuned models. Apache-2.0, self-hosted, no phone-home, and it runs today exactly as it did in June.
Honest dings
It is archived. The repository went read-only on 12/06/2026 with 392 open issues frozen, the last release was 2026.6.0 on 04/06/2026, the docs site is down and tensorzero.com now says only that the project is no longer maintained. That means no provider-API updates as models churn, no security patches, no support, and no MCP or A2A — the protocol layer never landed. The founders wound the company down having spent less than half of a $7.3M seed, with no debt, and returned the rest to investors, which is honest and also final: no acquirer, no foundation, and as of this audit no fork with meaningful release cadence.
Sources (10) — every claim traceable
Every audit lists the research it rests on — transparency and traceability are the product. Tools evolve: each audit is a snapshot of its audit date, and re-audits supersede older versions (kept below for reference).
- github.com/tensorzero/tensorzero — Repository: archived read-only 12/06/2026, Apache-2.0, 11,716 stars, 966 forks, 392 open issues, last push 11/06/2026 (GitHub API queried 03/09/2026) (accessed 2026-09-03)
- tensorzero.com — Official site as of 03/09/2026 carries one line: the project remains on GitHub but is no longer maintained (accessed 2026-09-03)
- raw.githubusercontent.com/tensorzero/tensorzero/mai… — Feature evidence: gateway with <1ms p99 at 10k+ QPS, 19 named providers, tool use, structured outputs, batch, embeddings, multimodal inputs, caching, ClickHouse observability, OTLP and Prometheus export, SFT/RLHF/GEPA/DICL optimization, evaluations, A/B experimentation. No MCP anywhere in the file. (accessed 2026-09-03)
- api.github.com/repos/tensorzero/tensorzero/releases — Last release 2026.6.0 published 04/06/2026; nothing after the archive (accessed 2026-09-03)
- news.ycombinator.com/item?id=48516504 — Co-founder and CEO Gabriel Bianconi, first-hand: decision to wind down, $7.3M raised in 2024, less than half spent, repo stays Apache-2.0 but unmaintained; calls the ~1% of global LLM API spend a best-effort estimate (accessed 2026-09-03)
- ai-tldr.dev/releases/tensorzero-archived-jun12 — Independent report of the 12/06/2026 archive at 11,560 stars and the return of unspent capital to investors (accessed 2026-09-03)
- future-stack-reviews.com/tensorzero-shut-down — Independent post-mortem 21/06/2026: no foundation adoption, no fork matching the original's cadence, and migration guidance splitting gateway, observability and evals across separate maintained tools (accessed 2026-09-03)
- dreaming.press/posts/tensorzero-shutdown-llmops-squ… — Independent analysis 04/07/2026 of the category squeeze: labs and clouds bundling gateways and evals, ClickHouse acquiring Langfuse, no debt and voluntary wind-down at TensorZero (accessed 2026-09-03)
- byteiota.com/tensorzero-shuts-down-what-oss-llmops-… — Independent report 14/06/2026 confirming the archive date, the ~1% traffic claim as a company figure, and the absence of a pivot or sale (accessed 2026-09-03)
- katrinajaneczko.net/tensorzero-shut-down-heres-my-t… — Practitioner account from a team running TensorZero in production: fork-and-maintain versus migrate, and what the abstraction was worth to them (accessed 2026-09-03)