About

Building the analytics layer multifamily never had

Property managers running 50–500 units are sophisticated operators who know their numbers matter. Rentnoi exists to give them the NOI visibility that enterprise operators have — without requiring an enterprise analytics team to run it.

The problem we're solving

Mid-market multifamily is flying blind

Property managers running 50–500 units are sophisticated operators. They know their numbers matter. But their data lives in three systems — a property management platform, a spreadsheet, and memory. Rentnoi changes that.

The enterprise property management world has CoStar, RealPage Analytics, and full-time data teams. The small landlord world has simple apps. The middle — operators running several hundred units across multiple properties — has spreadsheets and manual reconciliation.

Rentnoi is built for the middle. The operators who are sophisticated enough to know what NOI drivers matter but don't have the engineering resources to build custom analytics on top of their PMS.

NOI Formula
NOI = Gross Revenue
− Operating Expenses

Three levers: maximize revenue, control expenses, optimize leasing velocity. Rentnoi maps all three — in one platform — from your existing property management data.

Our story

Founded in Denver

Rentnoi was founded by CEO Sienna Kowalski, who spent five years in property operations roles at two mid-market multifamily companies in the Denver metro before founding Rentnoi. The frustration was always the same: the data to make better NOI decisions existed in the PMS, but getting it into a usable form required half a day of manual work that nobody had time for.

Rentnoi raised a $275K angel round in September 2025 to build the analytics layer — and started with the specific problems operators kept describing: expense variance they couldn't see in real time, rent roll gaps that weren't obvious until reconciliation, and lease expiration clusters that caught teams off guard.

The company is headquartered at 1515 Arapahoe Street in Denver — in the Denver proptech ecosystem, which has become one of the stronger centers for multifamily technology development in the Mountain West. Our team is 8 people as of 2025, all Denver-area.

Sienna Kowalski, CEO of Rentnoi
Sienna Kowalski
CEO, Rentnoi

5 years multifamily operations before founding Rentnoi. Denver-based. Focused on building tools operators actually use.

Team

The team

Sienna Kowalski, CEO of Rentnoi
Sienna Kowalski
CEO
Rentnoi CTO team portrait
Arjun Mehta
CTO
Rentnoi Head of Product team portrait
Valentina Cruz
Head of Product
Meet the full team
How we work

How we work

Operator-first
We ship features operators ask for, not features analysts write about. Every product decision starts with a conversation with someone running a portfolio.
Transparency
Pricing, data practices, and product roadmap are visible to customers. We don't hide costs, limitations, or the current state of our compliance program. What you see is what we are.
Precision
We don't use words like "AI-powered" without showing you the model output. We don't claim certifications we haven't earned. Numbers in our dashboards are traceable back to your source data.

Join us or work with us

We're hiring in Denver and building for operators across the Mountain West.