Convert Excel to a secure, multi-user web app.
Same logic your team already knows — now accessible from anywhere, editable by everyone at once, and backed by a real database instead of a shared file.
AI-accelerated delivery — our RalphAI assistant speeds every build.
20+ years
Building business apps for small and mid-size companies.
Clear, up-front quotes
No surprise invoices. We scope, then quote the work.
Progress updates every week. No black boxes.
Built on a modern React/Next.js + Node + SQL Server stack on AWS
Turn your spreadsheet into a web app — right now
Drop in an Excel or CSV file and watch it become a working app preview in your browser: schema-inferred forms, a clean table, and a real Add-record button. Your file never leaves this page — nothing is uploaded.
100% in your browser — your file is never uploaded, stored, or run. Nothing leaves this page.
Is this you?
Version chaos
There are six copies of the workbook on the shared drive and nobody knows which one is the real one.
No real multi-user access
Two people open it at once and one of them loses their work. Constant "file is locked" pop-ups.
Broken formulas
One dragged cell or copy-paste and a formula silently breaks — and nobody notices until the numbers are wrong.
No audit trail
Who changed what, and when? A spreadsheet can't tell you. Auditors and managers are stuck guessing.
Hitting size limits
The workbook is slow to open, crashes on save, or is bumping up against row/size limits as it grows.
Can't open on mobile
Sales is in the field, the warehouse is on a tablet, and nobody can get to the spreadsheet.
Imagine instead…
Real-time multi-user
Ten people editing the same data, no file locks, no lost work, no version sprawl.
One source of truth
A real database, not a file — the numbers are the same for everyone, every time.
Anywhere access
Same login from the office, home, a tablet, a customer site.
Mobile-responsive
Built for phone and tablet from the start — no extra app to install.
Audit trail
Every change is logged: who, what, when. Compliance ready.
Integrations
QuickBooks, Salesforce, Stripe, your warehouse system — talk to the tools you already use. Nothing to install.
Our streamlined 6-step process
- 1
Free System Review
Async-first. Send us your spreadsheet and we'll analyze it — no charge. We tell you what we see and what it would take, then get back to you.
- 2
Architecture & quote
We write up the architecture, data model, and integrations — then quote the work up front. No surprises.
- 3
Iterative build with weekly progress updates
You get a progress update every week, so you can course-correct early and never wait months to see where things stand.
- 4
Data migration + parallel run
We migrate your data and run the spreadsheet alongside the new app until you're confident.
- 5
UAT
Your team runs through the new app, tests the workflows that matter, and signs off before launch.
- 6
Go-live & ongoing support
We flip the switch, monitor the rollout, and stay on call. Support is ongoing — you're not on your own day one.
You’re in good hands
20+ years modernizing spreadsheets
We've seen every variant of "the Excel workbook that grew up." Nothing surprises us.
Clear, up-front quotes
We scope, then quote the work up front — no "a few more weeks."
Weekly progress updates
You get a progress update every week. No black boxes, no surprises at launch.
References on request
Real clients who've moved off Excel. Ask us, we'll connect you.
How a web app compares
| Capability | Excel spreadsheet | Custom web app |
|---|---|---|
| Access from anywhere | Tied to one PC / shared drive | Any browser, any device |
| Multiple users at once | File locks, lost edits | Real-time, no conflicts |
| Mobile / tablet | No | Built-in, responsive |
| Data integrity | Broken formulas, version sprawl | One source of truth, backed up |
| Security | One shared file/password | Role-based logins + audit trail |
| Reporting & integrations | Manual, brittle | Live dashboards + API integrations |
| Scales as you grow | Hits row/size limits | Grows with your data + users |
The cost of staying on spreadsheets
Answer four quick questions to see what the manual process costs your team each year — and roughly when a web app pays for itself.
Their rough hourly cost
How often bad data / rework bites you
How it’s calculated: hours × people × 52 weeks × hourly cost, plus a rework factor.
You’re spending roughly
$58,968/year
on this manual process.
A web app in the typical range often pays for itself in about 4 months.
Estimate — real numbers depend on your setup.
Most software projects land in the low-to-mid five figures and typically pay for themselves within about four months. You get a fixed quote you approve up front (no surprises), billed by milestone — or monthly for ongoing work.
What clients say
“The YittBox team has an incredible writer. I plan on using them for all my future scripts. They communicate well, and write a quality script on time. I would recommend them to anyone.”
— Andrew Schmidt
“Very responsive to changes and understood what I was trying to do from the start. Had some good suggestions for changes that I had not thought of that made the program work better.”
— Jason Taylor
“I'm thoroughly impressed with the YittBox team's development of my Portfolio. The work quality was excellent, and the experience of collaborating with them was overwhelmingly positive. Their communication was exemplary, ensuring we were always on the same page. One of the team's standout qualities was their adherence to deadlines - they consistently delivered on time, which kept our project running smoothly. Their technical proficiency in Portfolio development was evident throughout, demonstrating a solid skill set that met our project needs. I particularly appreciated the team's candor when we discussed solutions to my initial missteps. They quickly guided me towards the best outcome for the Portfolio, showcasing their ability to provide effective direction and resolution. I'd like to emphasize that this was my first time creating a Portfolio, working in Canva, and using Upwork. The only reason this process went so perfectly for me is that I had the opportunity to connect with the YittBox team. This has been an incredibly positive experience, almost unbelievably so. Given the success of this collaboration, I'm eager to work with YittBox again. Their blend of technical skills, reliability, and proactive problem-solving makes them an excellent choice for future projects.”
— Arnold Thornton
Converting an Excel spreadsheet into a web app
Converting Excel to a web app means rebuilding the process your spreadsheet runs — the data, the formulas, the reports — as a secure, multi-user web application that people open in a browser instead of a shared file. It’s the right move when a spreadsheet has quietly become mission-critical: several people need it at once, versions are getting emailed around, a wrong click can break a formula, and no one’s sure which copy is the real one.
What actually moves over
Your data comes across intact, and the logic your spreadsheet already encodes — the calculations, lookups, and rules — is rebuilt as the engine behind the app. The reports your team reads today are recreated so nothing familiar is lost. What changes is the fragile part: instead of formulas anyone can overwrite, the rules live in the app, and instead of one file at a time, everyone works in the same place with their own secure login.
Excel vs a custom web app
Excel is excellent for analysis, modeling, and one-off work — and there’s no reason to abandon it for that. It starts to strain when it’s doing a job it was never meant for: multi-user data entry, controlled access, an audit trail, mobile use, and validation that stops bad data before it’s saved. When a spreadsheet has grown into a system, a web app gives you those guardrails while keeping the workflow your team already understands.
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Read more →Explore the full Excel library
When a spreadsheet becomes the system of record, every manual edit is a risk: broken formulas, overwritten cells, and no audit trail. YittBox converts mission-critical Excel workbooks into real web applications with a proper database, permissions, and validation — so the numbers your business runs on stay right. Explore our full Excel library below.
Companies we've worked with
UPA Diesel
Nikz Nacks
Rack N' Action
1128 Capital
VALLEY CAR GROUP
GUIDELINE TEMPLATES
ADVANCED CRM SOLUTIONS
WAVERITAS
BATES CUSTOM STONE
SOUTHERN MISFITS OFF-ROADING
TOP TOYS THIS YEAR
PANN TV
Media Choice
M&A AssociatesOur promise to you
Fixed up-front quote
Approve the price before any work starts — no surprise bills.
You own everything
You own 100% of your code and data. No lock-in.
We work until it's right
We keep at it until it does what we agreed on.
Free review, no commitment
Get a real answer with no call and no obligation.
Worried about handing over your data? See how we keep it safe →
Led by Joe & Holly, Managing Partners — meet the team →
Frequently asked
How do I convert an Excel spreadsheet into a web app?
You move the same logic into a web app backed by a real database: we review the workbook, rebuild the calculations as a multi-user app, migrate your data, and you validate before go-live.
What does it cost?
We provide a quote after we review your spreadsheet. Every project is scoped to your data, users, and integrations — most land in the low-to-mid five figures.
How long does it take?
Most projects ship in 6–12 weeks from scoping. The exact timeline is in your quote — no "a few more weeks."
Will we lose data?
No. We migrate your data into the new system and run the spreadsheet in parallel until you've verified everything against the new one. Nothing flips until you sign off in UAT.
Can we keep using Excel during the transition?
Yes. During the parallel-run phase your team keeps working in Excel exactly like today. We only ask you to switch over after UAT.
Do you sign NDAs?
Yes. Mutual NDA is standard before we look at your file. Send us yours or we'll send you ours.
What about my existing reports?
Reports come over. We rebuild them in the new web app so they render in a browser and export to PDF/Excel on demand. The numbers stay the same.
Excel vs a web app — which is better?
For one person a spreadsheet is fine; for a team a web app wins on multi-user access, automatic backups, mobile access, security, and an audit trail — with no single point of failure. The trade-off is the upfront investment.
My spreadsheet has macros/VBA — can those come over?
Yes. We review the macros and VBA logic during the free system review and rebuild that same logic as proper application code — no more fragile, hard-to-maintain macros.
Get a free system review
Three quick steps. No call required — send what you have and we'll analyze it and reply within one business day.
- NDA on request
- Your file is never shared
- Reply within one business day
- No obligation
Not ready to send your file yet? Try the free Excel Workbook Analyzer →