Multi-tenant SaaS

SaaS ready for every customer.

Production-grade SaaS platforms with tenants, roles, billing and enterprise features built in from day one. Free working prototype in 1 day, then a production release at a fixed price and date.

Web & Mobile apps

Get your free prototype 30-min call · no commitment

app.saas.io/kestrel/billing

KKestrel Labs⌄

Dashboard

Projects

Members

Billing

Billing

Seats used19 / 24

API usage412k / 1M

Pro planSSO enabledAudit log

convex/billing.tsAI

export const usage = query({

args: { tenantId: v.id('tenants') },

handler: async (ctx, { tenantId }) => {

await requireMember(ctx, tenantId)

return ctx.db.query('usage')

.withIndex('by_tenant', (q) => q.eq('tenantId', tenantId))

})

Senior review · approved

Pipelinemain

Build
Testspassed
Senior review
Previewdeployed
Productionlive

Buildto launch

Day 1Week 1Week 2Week 3Live

Workspaces are liveSSO, roles and billing onnow

At a glance

One product. One price, one date.

The essentials, before you book a call.

UDEX builds multi-tenant SaaS products for founders and product teams. Production-grade SaaS platforms with tenants, roles, billing and enterprise features built in from day one. AI writes the code, tests and CI/CD, while senior engineers own the architecture and review every change.

1 dayFree prototypeNo payment, no commitment

FixedPrice and dateAgreed before we start

100%YoursCode, repository and accounts

Platform: Web and mobile, multi-tenant SaaS
Ships to: Production
Stack: Next.jsConvexPostgresStripeClerk
Quality: Senior review on every change, automated tests, CI/CD

How it works

Idea to production. In three steps.

AI does the heavy lifting. Senior engineers make every decision that matters.

01Day 0
Share the idea
A 30-minute call. We agree on the core flow, the scope and a fixed release date.
02Day 1 → release
AI builds, senior engineers decide
AI writes the code, tests and CI/CD. Senior engineers set the architecture and review every change. Your prototype is ready on day 1.
03Release day
Ship to production
The release goes live, and the code, repository and accounts are handed to you.

Who it’s for

Built for founders and product teams.

Here is where it works best, and where it doesn’t.

B2B SaaS founders

Workspaces, roles and billing from day one.

Products selling to enterprises

SSO, audit logs and admin consoles.

Usage-based businesses

Metering, plans and invoices.

Agencies turning tools into products

One codebase for many clients.

Teams rebuilding single-tenant apps

Move to a proper multi-tenant model.

Vertical SaaS

Industry products with tenant-level settings.

Not the right fit

Single-customer internal tools: see Internal Tools.
Products without a defined pricing model yet.
Certified compliance from day one, such as HIPAA or PCI audits.
Open-ended hourly work without a defined first release.

How we work

Six stages, one team.

All services

Pricing

Start free. Ship at a fixed price.

Two steps. The prototype costs nothing, and the release costs exactly what we agree.

Prototype

Free1 day

A working prototype of your core flow to test with users and show investors.

Key screens and the main user flow
Working on real devices and browsers
No payment, no commitment

Get the free prototype

Release

Fixed priceand date, agreed upfront

A production release, shipped to production, that you fully own.

Next.js, Convex, Postgres and the features agreed on the call
Automated tests, CI/CD and senior code review
Release to production and 100% code ownership

Start with a call

Fixed means fixed. No hourly billing and no surprise invoices: anything new is priced before it is built.

Book a call

Thirty minutes. Then your prototype.

Walk us through the idea, and we will scope the core flow and build your free prototype the next day.

Book a 30-min call

FAQ

Questions, answered.

Straight answers about cost, timing, quality and ownership.

How much does it cost to build a multi-tenant SaaS product?

The price is fixed for the agreed scope and set before work starts. You first get a free working prototype of the core flow in 1 day, then a fixed price and release date for the production version.

How long does it take to build a multi-tenant SaaS product?

A working prototype takes 1 day. The production release date is agreed upfront and depends on the scope; AI speed with senior engineering makes it much faster than classic development.

How is customer data separated?

Every record is scoped to a tenant, enforced on the server, with tests that prove one tenant can never see another.

Can you add SSO for enterprise customers?

Yes. SAML and OIDC SSO, SCIM provisioning and audit logs are standard.

How does billing work?

Subscriptions, seats and usage metering through Stripe, with invoices and a customer portal.

Is the prototype really free?

Yes, with no commitment. After a 30-minute call we build a working prototype of your core flow in 1 day, and then you decide whether to continue to the release.

Will the price go up during the build?

No. The price is fixed for the agreed scope. Anything new you want to add mid-build is priced separately and built only after you approve it.

Who owns the code?

You do, 100%. The source code, repository and accounts are yours, and the release ships to production under your name.

Is AI-written code safe to ship to production?

It ships only after senior review. Senior engineers own the architecture, security and code quality, and automated tests run on every change.

In practice