Web app · Operations · Spreadsheet · Sovereign
Search “custom web app instead of spreadsheet” and you get Caspio, Glide, Sheetcast and Retool — companies that put a skin on the sheet. Sometimes that is enough. It is not a product you own, and it is not what we sell.
We build a custom web app when the sheet is already the company: jobs, customers, inventory, a status the client should see without emailing you. That is a Sovereign. Fixed scope. You own the application on final payment. The sheet becomes an export.
Stay in the sheet if
One person uses it, the columns are honest, and a wrong cell is cheap. Buying software to feel organised is how you get two systems and the same chaos.
Leave the sheet when
Two people cannot edit at once without a fight. Customers ask for status you already typed somewhere. You paste the same row from email every morning. Someone’s laptop is the backup. That is the call.
- Good first app: a queue with a confirm button and a login.
- Bad first app: “AI that runs the business” on top of columns nobody named.
- Worse: a no-code replica you still cannot leave.
How we price it
Not from a blog calculator. A short call, then a statement of work: screens, roles, data, schedule, USD. Typically 50% to start and 50% on delivery. If the workflow is still a vibe, we will tell you to spend two weeks in the sheet first. That conversation is free. The build is not.
The steps — do these in order
- 01
Name the columns that are actually the company
Customer, job, due date, amount, status, owner. Delete the rest. If you cannot name them, you are not ready to build.
- 02
Name who may confirm a row
One person. If two people silently overwrite, a queue will not save you.
- 03
Write the job in one sentence
“Staff enter a job, I approve it, the customer sees status.” If that sentence has “and also AI,” cut the also.
- 04
Get a fixed statement of work
Screens, roles, data, price in USD, weekly increments. Sovereign. Nothing billed before you approve it.
- 05
Keep the sheet as an export
The app is the system of record. CSV out at night if you want it. The other way around is how you stay stuck.
- 06
Own the code on final payment
If the vendor keeps the app in their account, you bought another spreadsheet with a nicer URL.
If this is the work you need, write. You get a written scope, a price in USD, and a site or product you own. Nothing is billed before you approve it.
Keep reading
Retainer
Freelancer, one-off project, or a studio on retainer
Most “retainer vs freelancer” posts are written for freelancers. This is for operators choosing a $2,500 Origin, a custom SOW, or Relay at $1,500 a month.
Client portal
A client portal instead of a shared drive and a thread of PDFs
Scopes, invoices and files on one login the company owns — not another folder nobody can find, and not a SaaS you rent forever.
New Mexico
Internal tools for New Mexico operators who still run the company in a sheet
Quotes, jobs and follow-up do not belong in a shared workbook. A system the company owns — billed by a New Mexico LLC.
Mohamed Bellouch
Technological Innovation Engineer
Founder & CEO
Mohamed is a technological innovation engineer. He founded SINLE Technologies LLC to put agentic systems, product engineering and a next-wave studio under one roof — not another web agency. He leads which work we take, and the direction of every SINLE division.