AppCrib started as a shelf of developer utilities. JSON formatters, diff tools, cron helpers, color converters. Tools for people who sit at a desk with two monitors and strong opinions about tabs.
Then we shipped a drywall calculator, and a stud spacing tool, and a mulch volume estimator, and something changed in how we think about the whole catalog.
The people using those tools are not developers. They are standing in a garage, or halfway up a ladder, or in a rented skid steer with the engine running. They have one hand free. Their phone is the cheapest one in the house because it lives in a tool bag with a speed square and a fistful of drywall screws. We started calling it the shed phone, and it quietly became a design constraint for everything we build now.
The Math Is Real, the Tools Are Terrible
Here is the thing nobody tells you about the trades: they run on math that would make a first-year engineering student sweat.
A dipstick reading on a horizontal cylindrical tank is not a percentage. Half wet does not mean half full, because the cross-section is a circle and the volume is a circular segment integral wearing work boots. Crown molding meets a corner at a compound angle that depends on both the spring angle and the corner angle, and the saw settings are not intuitive to anyone. Conduit benders come stamped with multipliers that most electricians memorize without ever being told where the numbers come from. Rigging a load on two slings changes the tension in each leg as the angle flattens, and getting it wrong is not a rounding error, it is a dropped load.
Search for any of these problems and you find three kinds of results. A forum thread from 2011 where two people argue and neither shows the formula. A PDF chart scanned at an angle. Or a calculator site with fourteen ad units, a cookie wall, an email capture, and a result rendered in six-point font somewhere below the fold.
The math is centuries old and completely settled. The delivery is what's broken.
What a Shed Phone Actually Needs
Designing for the shed phone turns out to be a wonderful forcing function, because it strips away everything we were already suspicious of.
The tool has to load fast on a mid-tier phone with two bars of signal, which means no backend, no login, and no framework circus. All our micro tools are static pages that compute everything on the device. That was already the AppCrib architecture, so the trades tools inherited privacy and speed for free.
The inputs have to survive gloves and glare. Big touch targets, high contrast, no fiddly dropdowns where a number pad would do. One tool, one job, one screen. You enter the numbers the tape measure gave you and the answer shows up in units you can act on. Gallons to order. Studs to buy. The two saw angles, labeled, for the corner you are actually cutting.
And it has to show the work. The person on the ladder does not need to trust us. They need to be able to check us, because they are the one who signs for the materials. Every calculator we ship in this category explains the formula it just ran, in plain language, on the same page.
From One-Offs to a Toolkit
For a while these tools were scattered across the catalog as one-offs. A drywall tool here, a wallpaper estimator there, a paint coverage calculator somewhere else. Useful, but disconnected.
We are now building them as a deliberate family. Internally it is called Field Math: calculators for the measurements people take with a tape, a dipstick, an angle finder, or a level, in places where the wifi is bad and the stakes are physical. Several are through the build pipeline already and more are in it right now. When the set is big enough to stand on its own, it gets its own front door on the site, the same way our color tools and JSON tools have theirs.
Same rules as everything else we ship. Free, no account, no data leaves the phone, and every claim on the page traceable to a formula you can verify.
Why Bother, Honestly
The cynical read is that trade calculators are a search traffic play. And sure, the demand is real and underserved, we are a portfolio company and we do read our search console.
But the honest reason is that these are the most satisfying tools we make. Developer tools compete on marginal convenience against a hundred alternatives and a terminal command. Field math tools regularly beat the current best option by a mile, because the current best option is a forum thread, a laminated card in a gang box, or a guess.
When we say the pipeline exists so humans never find dumb stuff, this is the version of that promise we care about most. A wrong JSON indent wastes your afternoon. A wrong sling angle can put someone in the hospital. Tools for people who work outside deserve at least the same rigor as tools for people who work in the cloud.
So that is where a growing slice of the roadmap is pointed. Less glamour, more geometry. If your phone has drywall dust in the charging port, we are building for you now.