Construction Operating System
From the uploaded tender to the final progress bill: documents, BOQ, estimates, suppliers, site and billing in one place. AI does the repetitive work, your people make the decisions.
Today
How many spreadsheets, inboxes and notebooks does one of your projects live in today, from tender to final bill?
Hundreds of pages are read by hand, and risks surface too late.
It exists in six versions of Excel and nobody knows who changed what.
Every item is priced from scratch, and the formulas live in someone's spreadsheet.
The same request goes out 14 times, and subcontractors get a cut-up Excel and drawings by email.
The plan is on a whiteboard, the diary is written on Friday, and extra work never gets fully billed.
When an experienced person leaves, their prices, formulas and experience leave too.
Film
How a tender moves through the system, from the documents to supplier quotes and a priced bid.
How COS works
Reads documents and quotes, finds changes, suggests formulas, drafts the diary, measurement book and bills.
Every estimate, every supplier choice and every progress bill goes through one of your people.
Data is entered once and follows the job from tender to payment. Nobody retypes anything.
Click a price or a quantity to see where it came from: formula, quote, diary, document page.
COS does not replace your people. It takes away the work that does not make them better.
Features
Pick a stage of the job and see what COS does there. Screens are from the system prototype (Croatian interface).
Module 1 · Win the work · Tender
01AI tender review
The team and management know what they are getting into before the first hour of estimating.
02Versions and changes
No change slips through, and everyone knows what changed in their part.
03Management review
The team only works on tenders management believes in.
Module 1 · Win the work · BOQ
04Splitting the BOQ
No more six versions of Excel. Everyone works on the same BOQ.
Module 1 · Win the work · Estimates and formulas
05Resource base
Every estimate starts from your real prices, machines and people.
06Item estimate
Every item price is explained and checkable, down to the last hour.
07Formula library
Every next BOQ goes faster, and the knowledge stays in the company.
08Item recognition
A 247-item BOQ gets priced in hours, not days.
Module 1 · Win the work · Suppliers and subcontractors
09Supplier requests
Nobody chases anyone by phone and nothing gets retyped.
10Subcontractor packages
Subcontractors price exactly what you ask for, with the full documentation.
Module 1 · Win the work · Price and submission
11Bid price and submission
The bid goes out calmly, with known risks and a checked margin.
Module 2 · Deliver the project · Contract and plan
12Contract, orders, stock
What you bid is what you order and track.
13Schedule
Delays get fixed while they are still cheap.
14Work planning
Less idle time, fewer delays, fewer phone calls.
Module 2 · Deliver the project · Site
15Site diary
The diary is always up to date, and quantities are ready for the measurement book.
16Measurement book
No reconciling three sources, no waiting for signatures.
17Extra and additional work
Money for extra work does not get left on the table.
Module 2 · Deliver the project · Subcontractors and cash
18Subcontractors on site
You pay exactly for what was built, not a euro more.
19Progress bills and e-invoices
Faster payment and fewer disputes over quantities.
20Cash and feedback loop
The company learns from every site, and cash never comes as a surprise.
Estimate example
The estimate is saved as a formula with variables. Next time you enter the quantity and thickness, and the price is done.
| Resource | Type | Output / m² | Price | € / m² |
|---|---|---|---|---|
| Asphalt AC 16 surf | Material | 0.1224 t | €70.00/t | 8.57 |
| Paver | Machinery | 0.0067 h | €95.00/h | 0.63 |
| Tandem roller × 2 | Machinery | 0.0133 h | €55.00/h | 0.73 |
| Crew lead × 1 | Labour | 0.0067 h | €22.00/h | 0.15 |
| Asphalt worker × 2 | Labour | 0.0133 h | €17.00/h | 0.23 |
| Labourer × 3 | Labour | 0.0200 h | €13.00/h | 0.26 |
| Unit price | €10.57/m² | |||
How it connects
Asphalt AC 16: formula, €10.57/m²
Same supplier, same price, from the budget
1,200 m² laid, crew of 6, paver 9 h
1,200 m² on the contract item, confirmed by supervision
Item on bill no. 4, e-invoice sent
Real output and cost flow back into the formula
Every price and every quantity knows where it came from. Real site costs flow back into the formulas, so every next bid is more accurate.
Phone app for the site
Diary, photos and quantities are saved on the phone and sent automatically when the connection returns. The site manager reviews and signs the same day.
Who gets what
Tender ratings, risks, deadlines, margin and cash in real time.
BOQ split across the team, changes marked, owners alerted at once.
Formulas instead of manual analysis, prices with a source, more bids submitted.
Requests and subcontractor packages, quotes compared, orders at the quoted price.
Schedule, a diary that works offline, a measurement book with no reconciling.
E-invoices and payments with no retyping, cash forecast ahead.
Interactive walkthrough
27 steps, from the uploaded tender to payment. Each step shows what to click, as if you were working in the system. About ten minutes, works on a phone too. Interface in Croatian.
Opens in a new tab · demo.buildwithcos.com
Data and security
Tenders, estimates, formulas and documents belong to you. Export any time.
Your prices, formulas and supplier quotes are never visible to any other customer.
Data is stored in the EU, encrypted, with backups.
Role-based permissions and a log of who changed what.
We sign a mutual NDA before any data is shared.
Partnership
We are looking for a few founding partners in construction. We invest in the build together: you bring real tenders and your team's experience, we build the system around the way you work. Partners get every feature first and the best terms of use.
Built around you Features are built around your processes, forms and regulations.
We import your history We import old BOQs, price lists and estimates; they become your base and first formulas.
We measure together Hours per tender, bids submitted, estimate accuracy and billing day, from day one.
Workshop with your team. Your materials, machines and first formulas in the system.
First working version of Module 1 on your real tender.
Module 1 in full use.
Module 2: plan, site, diary, measurement book, subcontractors, billing and cash.
FAQ
Old BOQs, price lists and estimates are imported at the start. They become your resource base and first formulas.
Yes. The app saves everything on the phone, diary, photos and quantities, and sends it when the connection returns.
Excel and PDF export from day one. Integrations with your accounting and e-invoicing are built along the way, around the tools you use.
No. We start with Module 1 on one real tender and roll out the rest step by step.
No. You choose the tenders and upload the documents; COS reads them, flags the risks and tracks every new revision.
AI decides nothing and submits nothing on its own. Every risk, price and quantity shows its source, and an engineer confirms.
No. Your formulas, prices and documents are used only for your company.
Forms are aligned with the regulations that apply to your projects, in Croatia and Serbia.
Send us one past tender with its BOQ. We will show you the risks and estimates COS would produce.
Ivan Penava · founder, COS · Split, Croatia · [email protected]