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Idle Macs, private prompts, open models.
Umbra is a marketplace for private-prompt inference on attested Apple Silicon: it puts idle Macs to work and gives developers a home for the models incumbents will not host.
Machine owners host public models on hardware they already own and earn per token; developers reach them through an API that speaks the formats they already use. The hard part is trust, so prompt privacy is designed as a property of the system, not a policy: an adversarial provider should not be able to read your prompt. Apple hardware and APNs running-code attestation are live for admitted providers; signed per-response receipts are still pending.
That is the name. In a total eclipse, the umbra is the innermost shadow: the region where the light source is completely hidden from view. Your prompts run inside it, and attestation is what makes the darkness provable instead of promised — hardware and running-code identity are live; signed per-response receipts are still rolling out during alpha.
Monetize idle Apple Silicon
Turn idle Macs into an inference provider that hosts public open-weight models and earns per token, on hardware you already own.
The long-tail models incumbents will not host
Uncensored models and community fine-tunes, chosen and hosted by independent providers, on an OpenAI- and Anthropic-compatible endpoint. Keep your SDK, change the base URL.
Private prompts, by design
Prompts and outputs are decrypted in-process and never logged, written to disk, or stored. Apple hardware attestation and an APNs app-targeted nonce challenge are live for admitted providers; signed per-response receipts remain in progress.
An experimental alpha, built in the open
Umbra is a small experimental alpha. Every hosted model is a public, open-weight model an independent provider pulls with their own Hugging Face key, run in-process behind a confidential coordinator that never sees prompt text. We ship honestly and say what is not ready rather than overstate it.