Animation you can
measure, not guess.
Most animation is chosen by vibes. Folio Motion integrates the actual spring equation — stiffness, damping, mass — and reports how long your motion takes to settle, how far it overshoots, and whether it will jank on a real device. Then it hands you the CSS.
live integration
k=320 c=30 m=1
- settle
- 371ms
- overshoot
- 0.0%
- onset
- 52ms
Numbers above are the engine's own output for those parameters. Drag the dials in the lab to change them and watch every figure move.
0Hz
integration step
Springs are solved with a fixed-step symplectic Euler solver, so results are identical on every machine.
0bit
integrity seal
Every mutation is chained with SHA-384, so a spec's history can be replayed and proven untampered.
0factors
explainable score
Settle, overshoot, onset, velocity and accessibility — each with the measurement behind it.
What the engine actually checks
Four numbers that decide whether motion feels good
settle
< 400ms
under this the UI feels instant, over 600ms it feels broken
overshoot
0–20%
a hint of overshoot reads as physical; past 45% it reads as sloppy
onset
< 60ms
time to cover the first 10% of travel; this is what sells responsiveness
animated prop
transform / opacity
anything else forces layout or paint on every single frame
The product
Not a demo. A workbench.
01
Tune it
Drag stiffness, damping and mass — or move bezier control points. The score and the curve update on every change.
Open the lab02
Keep it
Save the spec to Postgres. Every spec is owned by your anonymous session and sealed into a tamper-evident chain.
See your specs03
Ship it
Export CSS with a reduced-motion fallback, a Framer Motion module, an SVG of the real curve, or a reviewable report.
Hand it to an agentLive from the npm registry
The libraries it advises on
Fetched 02:30 PM · Live registry data for 5 animation libraries, cached 900s.
Stop guessing how your UI should move.
The lab runs entirely in your browser, needs no account, and saves to a real database. Clone it if you want to self-host the engine.