Custom software and SaaS
Your software product, built and handed over
We build custom software end to end, from the data model to billing. It's multi-tenant if you plan to sell it, with Erica, our assistant, built in where it helps. Every project is scoped and scheduled before work starts, and you own the code and the infrastructure.
- Fixed quote before any work
- Most sites live in 14 days
- You own the code and the data
- A person replies within one business day
- Multi-tenant from day one
- A dated schedule per project
- You own the code
- Working software every week
What does custom software development cost?
Inerica Systems builds custom software and SaaS products: multi-tenant platforms, dashboards, billing and integrations, scoped and scheduled per project. Builds start at $12,000, with a fixed quote before work starts, and monthly plans from $699 cover running it and building new features. You own the code.
How the work runs
From the tool you run on to the product your industry buys.
Every engagement follows the same route: what is going wrong, what we build to change it, where a rule or a person decides, and what you have at the end.
The friction
The business runs on a patchwork
Spreadsheets, a booking tool and a billing app that don't talk to each other, and a process good enough that others in your trade might pay for it.
What we build
One system, built as a product
Architecture, data model, dashboards and billing built in weekly increments you can use, not status decks.
The boundary
Each customer inside their own walls
Tenant isolation, per-tenant sign-in and role-based access from the start, with every action in the audit log.
The outcome
A product you own
Full source, infrastructure-as-code and docs handed over. Run it yourself or keep us on to grow it.
What's included
Everything in one engagement.
Product engineering
- Architecture and data modeling
- Multi-tenant isolation and sign-in
- Billing and subscriptions (Stripe)
- Admin and customer dashboards
- Usage metering and limits
Scale and reliability
- Postgres with a caching layer
- Background jobs and queues
- Rate limiting and monitoring
- Automated tests and deployment
- Audit logging and role-based access
Erica, where it helps
- AI features scoped to the product
- Automated workflows for each customer account
- AI usage metered per customer
- Drafting for content and support replies
- Written limits on what the AI can do in your app
Built on
- Next.js
- React
- TypeScript
- Tailwind
- Python
- FastAPI
- PostgreSQL
- Docker
- Claude
- Gemini
Integrates with
- Meta
- Stripe
- Twilio
How it works
From idea to live, in four steps.
- 01
Scope
We turn your idea into an architecture, milestones, a dated schedule and a fixed quote.
- 02
Build
We ship working software every week, so you are testing the real thing instead of reading status decks.
- 03
Launch
We deploy to production with monitoring, backups and billing live.
- 04
Own
The full source, infrastructure-as-code and documentation are handed over to you.
Proof
Work you can check for yourself
10 sites built, 6 live on their owners' domains. These are real clients, and every one of them owns what we built.
- Case studyGolden Gate TransA ballpark price before anyone fills in a form, and every quote request routed automatically instead of waiting in an inbox.Read the case study
- Case studyJunkHunterA local crew you can book from the first screen, with booking, callback and call tracking behind it in one pipeline.Read the case study
- Case studyBay Area Landscaping MaterialsA storefront, coverage calculator and quote flow built around how the yard actually sells.Read the case study
Businesses we've built for
What it costs
A fixed price before any work starts
Every build is scoped and quoted. We tell you the number before any work starts, and it does not move afterwards.
Custom software, scoped to your business
builds from$12,000
- Architecture, milestones and a dated schedule before work starts
- Running it and building features: monthly plans from $699/mo
- You own the source code and the infrastructure configuration
Questions
What people ask before they start
How long does a first version take?
Custom software is scheduled per project. After scoping you get a dated plan with milestones, and because we ship every week you are testing real software early instead of waiting for a big reveal.
Is it really multi-tenant?
Yes. Tenant isolation, per-tenant sign-in, billing and AI cost metering are built in from the start, so you can take on customers without re-architecting later.
Do you handle billing and payments?
Yes. We integrate Stripe (or Stripe Connect for marketplaces) with subscriptions, usage-based billing, and customer portals so you can charge from day one.
What happens after launch?
You own the complete codebase and infrastructure configuration. We can stay on, on a monthly plan, to build features and run it, or hand it over cleanly to your team.
What does it cost?
Custom software builds start at $12,000. The quote depends on scope and integrations, and we send it, fixed, before any work starts.
Start here
Turn the way you work into software you own.
Tell us the process and who would use it. We'll send a free build plan with the architecture, the milestones, a dated schedule and a fixed quote.
- Fixed quote before any work
- Most sites live in 14 days
- You own the code and the data
- A person replies within one business day