Custom orthotics used to mean a clinic visit, a foam impression box, and a bill for several hundred dollars. RunFast‘s pitch is the modern shortcut: scan your feet with your iPhone, and a pair of insoles is 3D printed to match them, lattice structure and all. The “FAST” branding is printed right into the insole itself.
Watch the video above for the ordering process and first impressions, then read on for how scan-to-print insoles work and how they stack up against the alternatives.
How the process works
Scan-to-print insole services follow the same broad recipe. You use your phone to capture your feet, following guided prompts so the app can build a 3D model of each foot’s shape: length, width, arch height, and heel profile. That model becomes the blueprint. Instead of cutting a generic blank to your shoe size, the printer builds the insole for your foot specifically, which is the difference between “custom fit” as a marketing phrase and custom fit as a manufacturing process.
The visible signature of the RunFast insole is its lattice: a honeycomb-style printed structure rather than a solid slab of foam. Lattice printing is not just an aesthetic. By varying the density of the structure zone by zone, a printed insole can be softer under the heel, firmer through the arch, and flexible at the forefoot, all in one continuous piece with no glued layers to delaminate.
Why runners care about insoles at all
The insole that ships inside a running shoe is a liner, not a support device. It is a thin, flat piece of foam whose job is mostly to cover the stitching. For plenty of runners it is fine. For anyone whose arches ache after easy runs, whose feet tire before their legs do, or whose shoes wear unevenly along one edge, the insole is the cheapest component in the whole system to upgrade, and the one in direct contact with the problem.
A shaped insole supports the arch so your foot is not holding its own structure up every step, spreads load across the whole foot instead of a few pressure points, and stabilizes the heel. None of that turns a bad shoe into a good one, but it is why the same shoe can feel completely different with a real insole in it.
RunFast vs heat-moldable vs clinic orthotics
There are three tiers of “custom.” Clinic orthotics are the medical gold standard: a professional assesses your gait and prescribes a device, at the highest price and with the longest process. Heat-moldable insoles are the middle tier: a pre-shaped blank softens in your oven or hot water and takes an impression of your foot, semi-custom at a modest price. Scan-to-print aims at the clinic tier’s personalization with the middle tier’s convenience: a data-driven shape, made for your feet, ordered from your couch.
The honest caveat for the whole category: an insole made from a static scan captures your foot’s shape, not your gait in motion. Runners with a diagnosed condition or recurring injuries should still treat a clinician as the first stop. For comfort, support, and tired-arch problems in otherwise healthy feet, scan-to-print is a rational place to spend money before committing to the clinic route.
Living with them: fit and break-in
Any supportive insole changes how a shoe feels, and the category-wide advice applies here. Wear them for a few hours the first day rather than debuting them on a long run, and build up over a week as your feet adjust to being supported in new places. Move them between shoes rather than dedicating them to one pair if you rotate footwear, and check the fit in your roomiest shoes first: a shaped custom insole takes up more volume than the flat factory liner it replaces, so the tightest shoe in your rotation may not be the right home for it. None of that is a drawback. It is the normal behaviour of a device that is actually doing something.
Frequently asked questions
How do you scan your feet? With your iPhone, following the service’s guided scanning process, which builds a 3D model of each foot that is used to print your insoles.
What are the insoles made of? They are 3D printed in a lattice (honeycomb-style) structure, which lets different zones of the insole have different firmness: cushion where you land, support through the arch.
Are custom insoles only for runners? No. Runners are the headline audience, but anyone on their feet all day, or whose arches ache in flat stock shoe liners, is the same use case.
Do they replace medical orthotics? They are a consumer comfort and support product. If you have a diagnosed foot condition, treat custom insoles as a complement to professional advice, not a substitute for it.
Verdict
RunFast is selling the most interesting idea in footwear accessories right now: your next insole should be manufactured from data about your feet, not picked off a rack by shoe size. The iPhone scan removes the clinic from the process, and the printed lattice is a smarter structure than a slab of foam. If your shoes fit but your feet still complain, this category, and this execution of it, is worth your attention.
Browse custom running insoles on Amazon to compare RunFast with the heat-moldable alternatives side by side.