We build the platform builders run on.
A small team in San Francisco and Berlin obsessed with how contractors really work — and how AI fits into that loop.
Our story.
We started Core 137 after watching contractors, subs and estimators spend more time stitching spreadsheets, takeoff tools, cloud drives and accounting together than building. So we put the whole job on one platform.
We are building in the open — live today for subcontractors and estimators, with general contractors, freelancers and more opening in stages. Small team, big mandate.
A small team, large impact.
building in public
priced weekly
estimate → invoice
built in
From a takeoff to the whole job.
Core 137 begins.
A small team and one goal: end the tool soup contractors live in.
Estimating & the cost database.
Digital takeoffs, assemblies and a live materials + labor database across 38 US regions.
AI proposals & change orders.
Branded, e-sign-ready proposals from any estimate — plus AI change-order detection.
Subcontractors & Estimators goes live.
Estimate, propose, schedule, build and bill — one platform, self-serve.
Opening the rest of the platform.
General contractors, freelancers, vendors and more — rolling out from the waitlist.
What we believe.
Built for the field
If it does not work with muddy boots and one bar of signal, it does not ship.
Your numbers, protected
AI runs on your data and your cost book — never to train shared models.
One source of truth
Enter the work once. Estimate, proposal, schedule and invoice all read from it.
A small team. A clear mandate.
Quotes the team came across this quarter.
The first tool that feels built for how subs actually bid — not adapted from some office software.
Build the platform with us.
Spin up a free workspace in under a minute.