The billing desk for specialty subcontractors

The gap

Construction software grew up around the general contractor and the owner. The GC got Procore, the owner got draw management, and the subcontractor got a login to both. Most of the roughly 600,000 specialty trade firms in the US still run billing on QuickBooks, Excel and one person who knows where the pay app template lives.

The cash problem sits exactly there. Built's payment data shows owners paying GCs in about 25 days and GCs paying subs in about 57. Subs say they wait 51 days after a pay app while GCs believe they pay in 35. Both sides are describing the same gap, and only one of them is funding it out of payroll.

This is not a market nobody has noticed. It is a market where the funded companies went after the money flow (payments, early pay, credit) and the incumbents went after the GC. The sub's own desk, the work of building the pay app, chasing it through four different GC portals, tracking retainage and watching lien deadlines, is still mostly a person with a spreadsheet.

Why now

Retainage law is moving in the sub's favor. California capped private retention at 5% for contracts from January 1, 2026, New York voided private retainage above 5% in December 2025, and Colorado, Virginia, Ohio and Indiana changed their rules in 2025 and 2026. Every change is a new rule a small billing team has to apply correctly, job by job.

Reading construction paperwork got cheap. OCR models now process around a thousand pages per dollar, and the cost of running a model at GPT-3.5 level fell more than 280-fold between late 2022 and late 2024. A schedule of values, a change order and a lien waiver are exactly the kind of semi-structured documents that used to need a person.

Payments are being given away. Built made GC-to-sub payments free in October 2025, with lien waivers included. That is bad news for anyone selling payments to subs and good news for a product that sits upstream of them: once money moves for free, the scarce thing is a clean, approved pay app.

Who pays, and how they buy

The buyer is the owner or controller of a specialty firm doing roughly $3M to $50M a year: electrical, mechanical, drywall, concrete. Below that, the owner's spouse does the billing. Above it, the firm runs Foundation or Sage with a real accounting team.

They already pay for back-office software. Foundation Software, which sells accounting and payroll to small and midsize specialty contractors, reportedly does more than $200M in revenue. They pay for lien services by the notice. What they do not have is one tool built around their side of the pay app.

Money already moving

• 92% of subs floated payroll from their own money in the past year while waiting on GCs. siteline.com
• 54% of subs now build the cost of capital into their bids, up from 45% in 2024. billd.com
• 41% of suppliers raise prices on customers who pay late, by an average of 9%. billd.com
• Lien notices are sold one at a time, at $59 per recipient on Levelset. levelset.com
• GC-mandated payment portals charge subs a share of contract value, 0.22% up to $3,750 in one GC's documents. levelset.com

The wedge I would back

A billing desk for the sub, not another payment rail. It reads the contract and the schedule of values, drafts each month's pay app, submits it into whichever GC portal the job uses, tracks retainage and change orders against the contract, and counts down every lien deadline. The owner approves; the product does the clerical work.

I would price it against the hours it replaces, not against software budgets. Two thirds of subs spend more than 11 hours a month on pay apps. That is a part-time billing clerk, and a clerk is the comparison the owner will make.

What I would not fundAnother early-pay or credit product. Payments are heading to free, retainage caps shrink the pool of trapped cash, and the balance-sheet players (Billd, Constrafor) already have a head start and the credit lines to back it.

The founder I would back

A former project accountant or AR lead from a specialty contractor, paired with an engineer who has shipped document AI. The first ten customers come from their old firm's network and the trade association chapter they already sit in.

The test I would run on the founder: can they name the four GC portals their old firm billed through, and what each one rejected last month?

Who is already building

Risks

• The workflow belongs to the GC. Pay apps go into the GC's system, so a sub-side tool has to fit many portals instead of replacing them. procore.com
• Point tools in this layer have been absorbed rather than becoming platforms: Levelset into Procore, Flashtract into Trimble. hypepotamus.com
• Construction is cyclical. The architecture billings index read 47.2 in August 2026, below the 50 line that signals growth, which points to softer nonresidential work ahead. aia.org
• Most demand data comes from vendors who sell to subs, with samples of 492 to 800 and no independent audit. I weight it, but not fully. getbuilt.com
• Reading QuickBooks data now costs money: Intuit started metering read API calls in November 2025, which taxes any product built on the sub's ledger. apideck.com