Upside Down Research, LLC

Upside Down Research, LLC builds custom development and SaaS products for software engineering and site reliability engineering. We focus on delivering substance over superficiality.

Our products include Housecarl AuthZ, a SaaS/on-prem service for authorization, and Housecarl Arbiter, a formal reasoning engine built by UDR.

Housecarl AuthZ is one of the most advanced authorization systems in commercial play today; Arbiter productized the last 50 years of research on complex and conflicting logic systems into an advanced reasoner suitable for wide use.

News, technical writing, and other updates are available at the writing section. The latest writing is about our software stack.

Please reach out at hello@upside-down-research.com for further discussion. Alternatively, consider booking a call with the founder.

Thank you,
Paul Nathan,
Founder

No. II.

The Catalog

Products in Service.

Two products in service. Each carries a published specification; terms are fixed in writing before signature.

UDR-HC-01

Operational

Housecarl

AuthZ

Policy-as-contract authorization for production services.

Housecarl is one of the most advanced AuthZ systems in commercial play today. Policies match by string, prefix, regex, or glob. Domains compose into a lattice with diamond inheritance — every child inherits from every superior. Multi-tenant isolation is fluid: cross-tenant requests evaluate against the target tenant's policies, not the caller's. Sessions are signed, keys revocable, passwords hashed. No sidecars required.

Deploys on Kubernetes or Linux — customer-owned or as SaaS. Interfaces: gRPC and REST.

Visit authz.housecarl.cloud → · Obtain Housecarl →

Specification

Release	v1.0.0-prerelease
Deploys on	Kubernetes · Linux
Hosting	GCP · us-central1
Interfaces	gRPC · REST
License	Source-available, commercial

UDR-HC-02

In Service

Housecarl Arbiter

reasoner

A formal reasoning engine for complex and conflicting logic systems.

Housecarl Arbiter productizes the last fifty years of research on complex and conflicting logic systems into an advanced reasoner suitable for wide use. Built by UDR; available under commercial terms.

The reasoner accepts mixed declarative inputs, resolves conflict by ranked policy, and emits a deterministic explanation tree. Outputs are reproducible and fit for record.

Visit arbiter.housecarl.cloud → · Open Arbiter →

Specification

Release	Rolling
Hosting	GCP · us-central1
SLO	99% uptime
Interfaces	MCP · API
Inputs	Declarative, mixed-logic
Output	Deterministic explanation tree
License	Commercial