What Is TypeLLM? The Open-Source Answer to Typed Decisions

TypeLLM is the open-source project answering the question every closed platform provokes: can I have the interface without the vendor? It implements the typed-decision pattern, closed questions in, structured answers out, over open models you host yourself, which makes it the ecosystem's standing proof that the pattern and the product are separable things.

What it is concretely: a layer that takes your question and candidate answers, runs them against a self-hosted open model, and constrains output to the choice set, giving you the decision-model developer experience (no prose parsing, structure by construction) on infrastructure you control. What it is not: a claim of equivalent speed or calibration; those depend entirely on the model you put behind it and the serving stack you build, which is the trade in one sentence. Hosted Jev sells you reported fractions-of-a-cent verdicts with zero infrastructure; TypeLLM sells you sovereignty with a GPU bill and a tuning backlog.

When the open route genuinely wins, per the alternatives analysis: data-residency and compliance requirements a hosted API can't satisfy, extreme sustained volume where serving costs undercut per-verdict pricing, air-gapped environments, and the strategic comfort of vendor independence, which is a real line item even when the spreadsheet disagrees. When it doesn't: everything else, especially week one, where hosted speed-to-working compounds.

The quietly important part: because both worlds share the typed-decision interface, your actual assets, question sets, boundary clauses, calibration data, eval suites, port between them nearly unchanged. Build on hosted, keep TypeLLM as the documented exit, and the vendor-risk conversation with your security team gets one slide shorter.

Frequently asked questions

Is TypeLLM as good as Jev?

Wrong axis: TypeLLM is an interface over whatever model you host, so quality and speed are yours to provision. Reported hosted economics remain the benchmark to beat.

Can I migrate from Jev to TypeLLM later?

That's the design virtue: questions, choice sets, and calibration transfer; only the endpoint and serving change. Keep questions versioned per production discipline and migration stays a config story.

Who should start with TypeLLM?

Teams with hard residency or air-gap requirements, or existing GPU serving. Everyone else prototypes hosted first per getting started, with the exit documented.