Custom Software Development for US Companies
We build custom business software for US companies that have outgrown a spreadsheet or a legacy system. A senior engineering team in Bordeaux, France, already in production for a California client, with our price ranges in US dollars below instead of behind a form.
Book a free 30-min intro call
Already in production for a California company
A California company that installs and services industrial manufacturing equipment ran its shipping on a shared Excel workbook. We turned that workbook into a web platform with shipping requests, printed service reports and packing slips, and a workflow that enforces tracking numbers and authorizations. It went to production with the team's Microsoft sign-in the day after we received the file, and the team uses it every day.
Read the case study →How much does custom software development cost?
These are the ranges we work to, in US dollars. Most agencies in this market do not publish them, which makes budgeting harder than it needs to be.
| Scope | Indicative budget | What you get |
|---|---|---|
| First useful slice (one process) | $5,000 to $18,000 | One complete process replaced and running in production: a shipping or order flow, a quoting configurator, a single price book. |
| Complete business application | $18,000 to $45,000 | Several processes, roles and permissions, migration of your existing data, and integrations with your ERP, accounting or CRM. |
| Multi-department program | $45,000 and up | A scope spanning several departments, delivered in successive batches against agreed milestones. |
These figures are indicative and get confirmed after scoping. The biggest drivers are the number of exceptions in your processes, the integrations, and how much data has to be migrated out of spreadsheets.
Working with a team in France from the US
Bordeaux is six hours ahead of New York and nine hours ahead of San Francisco. That gap is smaller in practice than it sounds.
East Coast
Your morning, from 9 a.m. to noon ET, is our afternoon: three hours of live overlap with the engineers every working day. Calls can be booked until 5 p.m. ET.
West Coast
Calls can be booked until 2 p.m. PT, so a meeting fits inside your working day. What you send at the end of your day is usually done before you are back at your desk.
We work in writing first: a shared channel, short written updates, and a demo of working software at each step, so most decisions do not wait for a call. When a call matters, we schedule it in your hours.
Contracts, invoicing and code ownership
- Contracts and documentation are in English.
- We invoice in US dollars.
- You own the code, the infrastructure configuration and the documentation, and that is written into the contract.
- Each stage has a fixed scope and price agreed in writing before it starts, so a quote never grows silently.
- We contract from our French company, RFLKT SAS, trading as Reflekt Lab. We do not have a US entity or a US office, and we will not describe a mailing address as one.
Security and where your data lives
- Our platform runs on Google Cloud in the EU (Belgium) by default. A US region, or a Google Cloud project you own, can be set up for your project.
- Your team signs in with the accounts it already has, such as Microsoft or Google, with access by role.
- We are not SOC 2 certified. We answer your security questionnaire item by item, with evidence from the systems themselves rather than pasted policy text.
- For sensitive workloads, AI models can run on infrastructure you control instead of sending data to a third-party API.
What we do for US companies
Each of these has its own page with how it works and what it costs.
AI integration services →
AI inside the tools you already use: documents into your ERP, voice notes into orders, assistants that can safely update your CRM.
Legacy software modernization →
Move an aging system off an end-of-life stack in stages, while it keeps running, starting with a fixed-price audit.
Custom business software →
Replace the spreadsheet or legacy ERP that runs a process, one process at a time.
Fractional CTO →
Senior technology leadership, part time, billed by the minute for the time actually spent.
Custom software for a small business →
When it is worth it, when it is not, what it costs, and how to start small.
Who you'll work with
Hugo Matthaey
Founder, Engineering
Hugo co-founded Side, the French temporary-work platform, and saw it through to its sale. He now leads engineering at Reflekt Lab. The people on your first call are the engineers who build your software, not account managers relaying requirements.
Hugo on LinkedInThe team is in Bordeaux, France, and builds in Go and PostgreSQL. We are small on purpose: the same senior people stay on your project from the first call to maintenance.
Book a free 30-min intro callFrequently asked questions
How much does custom software development cost?
For a first useful slice covering one process, expect $5,000 to $18,000. A complete business application with several processes, data migration and integrations runs $18,000 to $45,000. Programs spanning several departments start around $45,000 and are delivered in batches. The biggest cost drivers are the number of exceptions in your processes and the amount of data to migrate.
Do you work with US companies?
Yes. A California industrial equipment company runs its shipping operations on a platform we built, in production since September 2026. We work in English, invoice in US dollars, and schedule calls in your hours.
Do you have a US office?
No. The engineering team is in Bordeaux, France, and we contract from our French company. We say so up front because a US address on a website is easy to rent and tells you nothing about who builds your software.
How does the time difference work?
Bordeaux is six hours ahead of the East Coast and nine ahead of the West Coast. East Coast clients get three hours of live overlap with the engineers every morning, from 9 a.m. to noon ET, and can book calls until 5 p.m. ET. West Coast clients can book calls until 2 p.m. PT, and what they send at the end of the day is usually moving overnight. We work in writing first, so most decisions do not wait for a call.
Who owns the code you write?
You do, and it is written into the contract. That includes the source code, the infrastructure configuration and the documentation. If you later move the project in-house or to another firm, we help with the handover.
Can our data stay in the US?
It can. Our platform runs in the EU (Belgium) by default, and for a project that needs US data residency we set up a US region, or deploy into a Google Cloud project you own. Tell us the constraint on the intro call so it is in the scope and the price from the start.
Are you SOC 2 certified?
No. We answer your security questionnaire item by item, with evidence from the actual systems: how access is granted, where data is stored and encrypted, how changes are deployed and logged. If your procurement requires a SOC 2 report from the vendor, tell us early and we will say honestly whether we fit.
How long does a project take?
A first useful slice covering one process typically reaches production in six to ten weeks from the signed specification, sometimes much faster when the process already lives in a well-used spreadsheet. A complete business application is usually three to six months, delivered in stages so parts of it are in use long before the whole is finished.
Tell us what your spreadsheet is doing to you
A free 30-minute intro call, in English, at a time that works in the US. You leave with a view on whether custom software is the right answer, and a rough budget band if it is.
