Fixology builds bespoke software for UK main contractors and specialist subcontractors: commercial systems for valuations, payment notices, CIS and retentions, subcontractor portals for RAMS and insurances, and offline site apps for diaries, snagging and labour returns. A commercial system with a subcontractor portal typically takes 12 to 16 weeks and runs alongside your spreadsheets for one valuation cycle before you switch. It connects to Sage, Xero or Procore, and the code is yours from day one.
What contractors are running today
Larger contractors tend to run an integrated construction ERP such as COINS or Viewpoint, with Procore or Asite for project collaboration. Smaller main contractors and specialist subcontractors more often have Sage or Xero for the accounts, a project tool like Procore or Fieldwire on site, and a commercial team that does the real work in Excel: valuations, variations, CVRs and the subcontract ledger.
That Excel layer is where bespoke software earns its place. It holds the knowledge that decides whether a job performs, and it is usually one corrupt file or one resignation away from trouble.
It is also worth being honest about when not to build. If you are a small contractor with a handful of jobs a year, a packaged tool and a tidy spreadsheet are probably enough. Bespoke work makes sense when you run enough live projects that commercial admin fills whole roles, when your trade makes the generic tools awkward, or when errors in valuations and retentions are already causing disputes.
Valuations, applications for payment and the Construction Act
Getting paid on time in construction is a process with legal deadlines attached. Under the Housing Grants, Construction and Regeneration Act 1996, as amended, most construction contracts need a clear payment mechanism with due dates, payment notices and pay less notices. Miss a notice and you can lose the right to dispute the sum applied for.
A good commercial system tracks each application against the contract, calculates the gross valuation, retention and previous certified amounts, and works out the notice dates from the contract terms. It then warns the quantity surveyor before a deadline passes, not after. It should handle variations and contra-charges properly, with the evidence attached, because that is where most disputes start. When a dispute does reach adjudication, a clean record of every application, notice and supporting photo is the strongest position a contractor can be in.
CIS, reverse charge VAT and retentions
Contractors in the Construction Industry Scheme must verify subcontractors with HMRC, make deductions at the right rate, and send monthly returns by the 19th of the month following each tax month. Add the VAT domestic reverse charge for construction services, and a subcontract payment run involves several rules that are easy to get wrong by hand.
Retentions are the other thing that goes missing. A typical subcontract holds back part of each payment, with some released at practical completion and the balance after the defects period. Firms with dozens of live and finished jobs often lose track of what is due for release. A register with release dates and automatic reminders, linked to practical completion and defects certificates, is a small piece of work with an immediate effect on the commercial team's workload.
Subcontractor onboarding and CDM paperwork
Every subcontractor package comes with a stack of documents: insurances, accreditation certificates, CSCS cards, RAMS for the works, and induction records. Under CDM 2015 the principal contractor has to plan, manage and monitor the construction phase, and that means knowing which documents are current before anyone starts work.
A subcontractor portal lets each firm upload its own documents, shows your team what is missing or about to expire, and blocks a package from starting until the RAMS have been reviewed and accepted. The same portal can take applications for payment, so the commercial team works from one place rather than an inbox, and every document has a clear history of who uploaded, reviewed and approved it.
Site apps that work below ground and above the signal
Site teams will not use a tool that needs a desk. A site app for daily diaries, labour returns, snagging, permits and photos has to be quick, usable with cold hands, and able to work offline in basements and steel frames. Records sync when the phone finds signal, with the time and location stamped on every entry.
This is often built as a cross-platform mobile app that feeds the same database as the office system, so a photo taken on site appears against the right variation within minutes. If you already use Procore or Fieldwire, we would rather integrate with them than compete with them, and add only the screens they do not do well for your trade.
Tenders, take-off and the golden thread
Tendering is the other place contractors lean on spreadsheets. A bespoke tender tool can import the client's bill of quantities, collect subcontractor returns through the portal, hold your own resource library, and track outcomes so you learn which work you win. When a tender is won, it becomes the baseline for the job, and the commercial system reports progress against it every month instead of someone rebuilding a workbook.
At the other end of the job sits handover. For higher-risk buildings, the Building Safety Act 2022 introduced a golden thread of building information that must be kept accurate and accessible through the life of the building. Even outside that regime, clients increasingly expect structured handover information rather than a box of folders. Software that captures product data, test certificates and as-built information during the job makes handover far less painful.
A typical brief: a groundworks subcontractor
Consider a hypothetical groundworks firm with 30 live sites. Applications go out from Excel, CIS is worked out in Sage, retentions live in a notebook, and site managers send photos over WhatsApp. The finance director cannot see what is due by project without a day of work.
A first phase would be the commercial system: projects and packages, applications for payment with notice dates, CIS and retention tracking, and a link to Sage so payments are posted once. A second phase would add the site diary app, using photos as evidence for variations. Each phase is useful on its own if the second never happens.
Why contractors choose Fixology
Our ambition is to be the UK's leading bespoke software company for construction, and that means building around how the job really runs, not a meeting-room version of it. Discovery includes time with the QS, the site manager and the accounts team, and produces a written specification you could take elsewhere if you chose. Our guide on how to write a software specification shows what that document contains.
A senior UK team then builds in two-week sprints, with a working demo on a test link after each one. The code sits in your repository and the hosting in your cloud account in UK or EU regions from day one, and we support the system after launch. Our how we work page explains the sprint, ownership and support model in full.