Stop Googling when to replace your air filter.

AI handles the research, sets the reminders, and syncs them with the calendar and apps you already use.

Your plan is ready.

The right manual, read.Useful guidance matched to what you own.

The care, planned.Clear timing, steps, supplies, and safety.

What comes next, remembered.Trusted reminders keep you ahead.

Build yours in Castellan.

On Android? Join the waitlist.

Built for the systems that keep a home running Clear guidance, not gadget control Every AI result stays editable A real product, not a concept

Why we build

For people who take ownership.

Thomas Rizzie and Javier Garcia started Sweat Tech with a simple belief: people who choose hard things, carry real responsibility, and intend to win deserve serious tools. We build for people who expect more from themselves—and from the technology they trust.

Castellan began with the responsibility closest to us: our own homes. Even as engineers building complex systems and pushing AI to its practical limits, we were still handed buried manuals, invisible maintenance, and expensive surprises. The problem was not effort. Our homes had no operating system.

We built Castellan to give capable homeowners the leverage to stay ahead.

Meet the founders and read the full story

Castellan founders Javier Garcia and Thomas Rizzie — **Javier Garcia & Thomas Rizzie**AI engineers, homeowners, and co-founders of Castellan

How we build

Turn complexity into leverage.

Castellan applies engineering discipline and modern AI to research, organize, and remember the care a home needs. It turns scattered evidence into useful context and clear next actions—so taking ownership does not mean carrying every detail yourself.

Understand what you own

Start with the exact appliance, system, or important item you own—not a generic checklist.

Do the research

Turn manuals, photos, receipts, and details into useful context and care you can act on.

Keep you ahead

Surface what matters next with clear reasoning—without guilt, false urgency, or noisy alerts.

Available now for iPhone

Bring the same standard home.

Download Castellan on the App Store, or join the Android waitlist.

Available on the App Store

Castellan AI: Home MaintenanceSchedules, Reminders & Repairs

Start with one item in your home.

Try your first item analysis free on iPhone. Keep the item and continue with an auto-renewable subscription: $4.99/month or $39.99/year.

Android waitlist

Get the Android launch email.

One email when Castellan is ready for Android. No launch spam.

The product today

The maintenance plan your home should have come with.

Castellan investigates the item, builds a personalized maintenance plan, and remembers the details and decisions that make future care easier. AI does the work. You stay in control.

Start with whatever evidence you have.

A photo, a sentence about the item, or a saved PDF is enough to begin. You can fill in the rest when you have it.

Photo-assisted intake
Descriptions and manual entry
PDF documents and records

Castellan first-item screen with photo, description, and PDF intake options

Castellan figures out what you own—and what it needs.

Castellan enriches the record and builds recurring care. You review the result and change anything that does not fit your home.

Editable item identity and records
Recurring care plans
Warranty, ownership, and replacement details

Castellan first-item result showing an identified dishwasher, saved sources, and prioritized maintenance

Your whole home stays in view.

Today, Upcoming, Pending, and Activity turn scattered maintenance into one calm system.

Care organized by what needs attention
Upcoming work stays visible
Home items and history in one place

Castellan home screen showing Today, Scheduled, Pending, Activity, and saved home items

Know what to do—and why it matters.

Each plan explains the timing, effort, value, preparation, and safety behind the work. Then you decide what happens next.

Clear next care and effort
Guided steps, supplies, and safety
Complete, skip, or remind later

Castellan maintenance plan showing next care, effort, why it matters, and completion options

Context that compounds

Castellan doesn’t just build the plan. It remembers it.

Details, decisions, and completed care stay attached to the item—so knowledge stops disappearing into drawers, inboxes, and memory.

Remembered context

Everything important stays with the item.

Identity, care, supplies, documents, notes, and ownership details remain editable and easy to find.

Castellan dishwasher details with care, supplies, activity, make, and model information

Calm accountability

What you handled stays handled.

Completed care, skipped work, and supporting evidence form a practical history—not a guilt-driven backlog.

Castellan activity history showing completed dishwasher care and the original item creation record

Free homeowner guide

Just got the keys?

Start with a practical first-30-days checklist. Use your inspection report to prioritize, record the equipment you own, and know when to call a professional.

Read the free checklist

The builders behind Castellan

We build the tools we need to win.

Thomas brings air-traffic, aerospace, and defense systems thinking. Javier brings modern AI/ML research and production agentic systems. Sweat Tech is where those disciplines become serious products for people who take ownership.

Read our story

Founder Pricing

Founder Pricing is live.

We built Castellan for our own homes. Download it now and keep Founder Pricing while your subscription remains active.

AI-assisted items and personalized maintenance plans
Documents, notes, warranties, and history
Reminders and calendar feed

^$4.99per month

or save with annual

$39.99per year

Download CastellanAvailable in the iPhone app. Continuous active subscription is required to preserve the Founder price.

Questions, answered

Know exactly what you’re getting.

Still deciding? Email support@mycastellan.com.

Why did you build Castellan?

We founded Sweat Tech to build serious software for people who take ownership. Castellan applies that mission to our own homes: engineering discipline and modern AI replace scattered research, invisible maintenance, and memory with a system that helps homeowners stay ahead.

How much does Castellan cost?

Download Castellan for iPhone and try your first item analysis free. An auto-renewable subscription is required to keep the item and continue: $4.99 per month or $39.99 per year. Review the price and renewal terms in the app before purchasing.

Is Castellan available now?

Yes. Castellan is available now on the App Store for iPhone. Android homeowners can join the waitlist.

What kinds of information can I add?

You can start an item with text, a photo, or a PDF. You can also add and edit item details, warranties, ownership records, documents, notes, expected replacement information, and a display image.

Can I correct what the AI finds?

Yes. AI-assisted results are a starting point, not a locked record. You stay in control and can edit your item information and care details.

Does Castellan replace a qualified professional?

No. Castellan organizes information and offers practical maintenance guidance, but it is not a substitute for manufacturer instructions or licensed professional advice. Stop and get expert help when a task involves safety, code, gas, high voltage, structural work, or anything outside your experience.

For people who take ownership

Win at home.

Download Castellan

Available now on iPhone

Download Castellan or join the Android journey.

Built for our homes. Ready for yours.