JavaScript Animation Maker
Every frame drawn in code.
You just describe it.
An agent on Claude Opus 5.5 writes the JavaScript that renders every frame
and composes the soundtrack in code. No keyframes, no timeline, no terminal.
What is JavaScript animation?
A film written as code.
Rendered fresh every frame.
iArt.ai's Animation mode turns a one-sentence description into a JavaScript animation: a short film in which every frame is rendered by code that an agent on Claude Opus 5.5 writes. Type is set as real text, shapes and paths are drawn in SVG, and a canvas layer paints anything hand-drawn, particles or textures; each frame is a function of time, so the film plays, seeks and exports the same way. The music and sound effects are synthesized in code with the Web Audio API.
iArt.ai puts that method in a browser tab. Its Animation mode is an agent on Claude Opus 5.5: you describe the film, it plans the beats and shots, writes the animation code and the score, checks its own stills, and plays the result in your browser. There is no default style. The look comes from the subject and your words, so a payments explainer and a bedtime story for a two-year-old don't look alike.
Why it spread now: drawing a whole film in code leans on a model's spatial reasoning, taste, and ability to write long, careful code, and on its ability to look at its own frames and fix them. With Claude Opus 5.5, code-drawn films became good enough that people started sharing them, and "every frame in JavaScript" turned into its own genre.
For the full definition, see what JavaScript animation is. To do it yourself step by step, read how to make an animation with Claude Opus 5.5.
Claude Motion not on your plan? See four ways to make the same kind of animation without it.
Showcase
Films drawn entirely in code.
Each film was made in iArt's Animation mode from the first sentence of the prompt under it, with every frame and every note written in code. One sentence already makes a good film. The rest of each prompt is the brief we wrote from the film: its shots, look and sound. Try sends the whole prompt, so you get a film close to this one, not a copy.
A 40-second film in two acts about how a seed becomes a tree: act one underground (the seed cracks, roots reach down), act two above ground (the shoot breaks through, seasons pass, a tree). Same character style in both acts, one continuous score.
IDEA: One little acorn with a face is the hero throughout, seen in a fixed side-on cross-section with soil below, sky above. It wakes, roots, sprouts, becomes an oak, lives through the seasons, and ends by dropping a new acorn, closing the loop.
0–4.5s: brown soil layers under rain; a tiny acorn sleeps underground above a pebble. A small grey badge appears top left: "Act I · Below". Drops seep down toward it.
4.5–9s: close-up: three drops land on its cap, its eyes pop open with a smile, the shell cracks and a pale first root pushes downward.
9–19.5s: wide again. The root drives down, curves around the pebble and branches into side roots. A green shoot pushes up through the soil, pausing just below the surface.
19.5–25s: the shoot breaks through. Badge changes to "Act II · Above". Two rounded first leaves unfold and spread; the seedling smiles up at the sky.
25–30s: the stem thickens into a trunk, the acorn's face still at its base. Branches grow and burst into round green leaf clusters with small pink blossom dots; a warm sun rises upper right.
30–33s: autumn. The sky warms; the canopy turns golden orange and leaves drift down to the ground.
33–36s: winter. Bare branches, snow falling, a white layer building on the soil. The face sleeps calmly.
36–40s: spring. The snow melts, green canopies pop back with blossoms, an acorn ripens on a branch, falls and lands on the soil with two small bounces.
LOOK: soil in deep chocolate #4A3322 and umber #5A3D28 with tan flecks #9C8471; sky parchment cream #EBE5D8; acorn golden ochre #D89849 with chestnut cap #8C5A28; stem green #88A878; foliage sage #94B097 and olive #5F8265, autumn orange #C8873E, blossom coral #E28A7A; sun amber #E2A35B. Flat shapes with light paper grain, simple line roots and branches, round canopies. Badge: small grey #7E858C rounded box, white text.
MOTION: calm, readable, with pauses between each stage of growth. Springy squash and stretch on the crack, leaf pops and landing; smooth easing on root and branch growth. Seasons change in place with colour shifts, falling leaves and snow.
SOUND: one unbroken, unhurried fingerstyle acoustic guitar score, thinning in winter, lifting for spring. Drip pings underground, a crisp shell crack, soft pops on eye-open and when the shoot breaks through, birdsong above ground, woody rustles, an autumn breeze, quiet winter wind, a spring chime, and a hollow thud as the new acorn lands. No narration.
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How do noise-cancelling headphones actually cancel noise? Short vertical explainer for TikTok, ~20s.
IDEA: One cutaway earcup on a listener's head is the whole diagram. Red noise wave in, mic hears it, chip flips it teal, speaker plays it, red plus teal add to a flat line. A bottom meter drops LOUD, MUFFLED, QUIET.
0–2.4s: an annoyed listener faces a fan-like engine labelled "ENGINE HUM". A red sine wave travels into his ear; the bottom meter "NOISE AT YOUR EAR" fills red to "LOUD". Question card drops in at the top: "How do headphones erase noise?"
2.4–3.8s: over-ear headphones slide down onto his head and open into a cutaway: outer mic, chip, inner speaker. The cushion damps the wave; meter falls to "MUFFLED".
3.8–7.6s: punch in on the earcup. Card: "STEP 1 / A mic outside hears the noise". A pulsing ring marks the mic; a screen on the chip traces the red wave.
7.6–11.3s: card: "STEP 2 / A chip flips it upside down / every peak becomes a dip". The wave on the chip screen flips vertically and turns teal.
11.3–12.6s: card: "STEP 3 / The speaker plays the flipped wave". The speaker sends the teal wave into the ear alongside the red one. Equation: "NOISE" + "FLIPPED" = "YOU HEAR".
12.6–15.2s: card: "PEAK + DIP / They cancel out / the hum mostly disappears". Red and teal overlap and flatten into one grey line; meter shrinks to "QUIET" in green.
15.2–18.8s: slight pull back. Card: "THE CATCH / Best on steady hums like engines & fans / sudden sounds get through more".
18.8–22s: reframe on the now smiling listener. Four lines stamp on one by one: "Hear it." "Flip it." "Play it." "Quiet." Hold.
LOOK: warm off-white paper #F1EFE8 with fine grain. Charcoal #22252A headphones and outlines, warm grey #7F7C77 clothes and parts, coral red #D84337 for the noise wave and LOUD, teal #26B5A1 for the flipped wave, forest green #2D6A4F for QUIET. Minimal flat infographic: cutaway diagram, pill badges, thin line waves. Bold sans headlines, small tracked caps labels, text kept in the upper and lower thirds.
MOTION: clear cause-and-effect pace; each card holds one to two seconds to read, then swaps with a quick slide or dissolve. Props move fast with a snappy ease-out; waves scroll smoothly and continuously.
SOUND: warm fingerstyle acoustic guitar with soft piano and a light beat, around 90–100 BPM, under a steady low engine drone at the start. A click and muffled filter sweep as the headphones seal, blips on the mic, a rising synth whoosh on the flip, then the drone cuts out abruptly at the cancel. Soft woodblock pops on each final line, chords resolving. No narration.
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Why is the sky blue? A 20-second explainer in the style of a 1950s science textbook.
IDEA: One illustrated textbook page. Follow a sunbeam into the air: molecules knock the short blue waves off in every direction while red passes straight on, and that scattered blue reaches a boy's eye from all over the sky.
Throughout: header "CHAPTER 7 · LIGHT AND THE AIR", page "143", a title at the top, a "Fig." caption at the bottom, all typed on letter by letter.
0–3.8s: a boy in a blue cap in a field, a crosshatched red sun above. Title: "Why Is the Sky Blue?" Caption: "Fig. 7-1. On a clear day the whole sky looks blue. But sunlight itself looks white. Where does the blue come from?"
3.8–7.6s: push in to the sun; a white beam carries a long red wave and a short blue wave side by side. Labels pop in: "WHITE SUNLIGHT", "RED: LONG WAVES", "BLUE: SHORT WAVES". Title: "1. Sunlight is a mix of colors". Caption: "Fig. 7-2. White sunlight holds every color of the rainbow. Red light travels in long waves; blue light in short ones."
7.6–12.6s: along the beam among paired-circle molecules ("AIR MOLECULE"), the blue wave hits one and sprays out in rings: "BLUE BOUNCES OFF IN ALL DIRECTIONS". The red wave carries on: "RED PASSES STRAIGHT ON". Table top right, "LIGHT SCATTERED BY AIR": RED 1x, BLUE counting up to 6x. Title: "2. Air scatters the short waves". Caption: "Fig. 7-3. Tiny molecules of air knock short blue waves off in all directions, about six times more than long red ones."
12.6–16.4s: back to the field; dashed blue lines run from molecules all over the sky into the boy's eye ("YOUR EYE"). Title: "3. Blue arrives from every direction". Caption: "Fig. 7-4. Wherever you look, scattered blue light is coming toward your eye. So every part of the sky looks blue."
16.4–20s: full diagram holds. Title: "In Short". Caption becomes a bordered box: "The air scatters blue light out of sunlight, all across the sky. That is why the sky is blue." Hold.
LOOK: aged newsprint #EDE7D7, vermilion #D75D4E for sun and red wave, cornflower blue #4B78A4 for blue wave and sky lines, mustard ground #C4B17B, olive tree #8A7D58, faded charcoal #22201E lines and text. Lithograph print feel: fine horizontal ruling, crosshatch shading, a double-ruled diagram frame. Bold sans titles, plain sans captions, caps labels.
MOTION: calm classroom pace with holds for reading. Waves travel at steady speed; scatter rings expand smoothly, no bounce.
SOUND: warm, minimal electric piano chords around 80 BPM. Typewriter clacks on all typing, no whooshes, a resolving chord and one last key strike. No narration.
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Black-and-white ink woodcut style, rough carved lines on off-white paper. A girl folds a paper boat and sets it into the rain gutter; as it drifts through the city at night, every window it passes lights up and someone folds another boat. Short hand-lettered captions. 25 seconds, 16:9.
IDEA: One paper boat drifting left to right along the gutter is the spark. Every window it passes snaps on, and the light spreads like a chain reaction until the whole city glows and the gutter is full of boats.
Captions: lowercase hand-lettered white text in a black banner at the bottom, one per shot.
0–2.6s: a dark, hatched, rain-soaked skyline inks in on off-white paper, a small girl sitting on her front steps, rain lines jittering. Caption: "a dark, wet city".
2.6–5.1s: close-up of her mittened hands folding a cream sheet: triangle hat, brim, pop open into a boat. Caption: "she folded one boat".
5.1–7.6s: the girl with pigtails reaches down from the stoop, sets the boat on the gutter stream and lets go; it drifts right, bobbing. Caption: "and let it go".
7.6–12.6s: track right with the boat past dark facades. A ground-floor window bursts on with cream light and pointed rays, a silhouette inside; neighbours pop on; from an upper window someone drops another boat. Caption: "one window woke".
12.6–15.1s: wider street. Windows pop on in a ripple along the whole block; several boats now float together. Caption: "then the next street".
15.1–20.1s: the opening skyline again; light spreads across tenements and far towers until hundreds of windows glow. Caption: "then the whole city".
20.1–22.6s: low tracking shot along the curb: dozens of boats in a tight convoy, silhouettes watching from lit windows. Caption: "boats, and more boats".
22.6–25s: her building, every window lit; the girl sits in the central arched window holding a folded paper bird. Caption: "it started with one." Hold.
LOOK: strictly two tones like a linocut print: off-white paper #F3EFE6, carbon black #161412 for buildings, figures and banners, bright cream #FFFDF8 for window light and boats. Rough carved lines, heavy crosshatching, spiky ray bursts around lit windows. Flat side-on framing, water line low.
MOTION: animated on twos, hand-printed feel. Folds and windows snap on instantly with a short ray burst; boats drift smoothly with a gentle bob. Hard cuts; the only camera move is a slow pan along the water. The light spreads faster and faster.
SOUND: reflective fingerpicked acoustic guitar around 75–80 BPM, melancholy turning hopeful, over continuous rain hiss. Paper creases on each fold, a soft water dip, a warm switch click and small chime per window, clicks multiplying as the city lights up, a last chord ringing into the rain. No narration.
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Paper cut-out collage style, like a children's picture book made of construction paper. A little boy at his window can't sleep, so a small friendly cloud drifts down over the rooftops, borrows a bit of moonlight and glows like a nightlight until he dozes off. 20 seconds, square 1:1.
IDEA: One small smiling paper cloud is the hero: it drifts to the moon, soaks up its golden light, then floats down beside the boy's window. The film is the cloud turning from plain cream paper into a glowing nightlight.
0–3.3s: wide shot of a sleepy town at night: purple paper gabled houses, deep blue starry sky, a big textured full moon upper right. In a warm yellow attic dormer, a boy in blue leans out and looks up.
3.3–6.7s: cut to a medium close-up of the boy framed in the glowing dormer. He yawns wide, rubs one eye with his fist, then rests his chin on his folded hands on the sill.
6.7–10s: back to the wide sky. A fluffy cream paper cloud with a smiling face drifts in from the upper left and glides slowly across the stars toward the moon.
10–13.3s: close-up on the moon. The cloud eases up against its left edge and nuzzles it. Soft yellow light pulses between them, sparkles twinkle, and warm gold spreads through the cloud from inside. It blushes and smiles.
13.3–16.7s: medium-wide on the rooftop. The now golden, glowing cloud floats down on a slow eased arc and settles gently right beside the open dormer window.
16.7–20s: medium shot of the window and the glowing cloud. Tiny yellow star sparkles drift around them. The boy's eyes grow heavy and close with a contented smile as he dozes off. Hold in stillness to the end.
LOOK: midnight indigo sky #1E2243 and #262B54, plum and slate-purple rooftops #3C335C and #4D476D, warm lamp yellow windows #FED466 and #F6AD3C, creamy moon #F8E7A2 and #EED37A, cloud cream #F4EEDC turning golden. Everything is cut from textured construction paper: fibre grain, stippled roofs and sky, torn deckled edges. The glowing window anchors the centre; moon and cloud live in the upper third.
MOTION: slow, low-energy, lullaby pace. The cloud drifts smoothly with soft eased stops at the moon and at the window, with a gentle squash and stretch as it floats. The boy moves like a paper puppet: stepped blinks, swapped mouth shapes for the yawn, a simple arm rub.
SOUND: a slow, gentle lullaby on fingerpicked nylon-string guitar and warm acoustic bass with soft celesta and glockenspiel accents. Magical chimes and a soft sparkle sweep when the cloud touches the moon and fills with light, faint twinkles as it descends. The music never stops. No narration.
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¿Por qué la Luna cambia de forma cada noche? Un video corto para mi canal de ciencia para niños, texto en español.
IDEA: Un niño mira la Luna; la cámara entra en diagramas sencillos (Luna medio iluminada, órbita, cuatro fases) y vuelve al niño, que dibuja la Luna entera con el dedo. Unos 40 segundos, formato cuadrado 1:1.
0–5s: un niño de espaldas, jersey naranja, en una colina bajo un cielo estrellado, mira una Luna creciente. Se escribe letra a letra "¿Por qué la Luna cambia de forma cada noche?" ("cambia de forma" en amarillo). Una etiqueta bajo la Luna cambia "noche 3", "noche 7", "noche 11", "noche 15", y la Luna crece hasta llena.
5–16s: zoom a la Luna, que se oscurece: "La Luna no tiene luz propia." Un Sol amarillo entra por la izquierda con rayos discontinuos: "La ilumina el Sol." La mitad que mira al Sol se vuelve crema, la otra azul oscuro; etiquetas "mitad iluminada" y "mitad oscura". Luego: "El Sol siempre ilumina la mitad de la Luna."
16–26.5s: diagrama desde arriba: Sol a la izquierda, Tierra al centro, órbita discontinua. Arriba "La Luna gira alrededor de la Tierra." y, en amarillo, "El ciclo completo dura unos 29 días y medio." Abajo a la derecha, "Así la vemos:" muestra la fase. La Luna, entre el Sol y la Tierra ("Luna nueva"), avanza en sentido antihorario a saltos de un cuarto: "Cuarto creciente", "Luna llena" (detrás de la Tierra), "Cuarto menguante" y otra vez "Luna nueva".
26.5–34.5s: "Cada noche vemos un trozo distinto de su lado iluminado." Cuatro círculos en fila se llenan uno a uno con las fases y sus nombres. Debajo, una flecha amarilla curva de derecha a izquierda: "...y vuelta a empezar".
34.5–40s: de vuelta al niño. Señala la Luna creciente y una línea amarilla discontinua recorre su borde oscuro hasta cerrar el círculo. "La Luna no cambia de forma: cambia cuánto vemos de su lado iluminado." ("cambia cuánto vemos" en amarillo). Se mantiene.
LOOK: cielo azul noche #141838 a #0B0E23; Sol y palabras clave #F8C847; lado iluminado crema #F6F2DC con cráteres #D3CEB0; lado oscuro #2B3463; Tierra #2A74D9 con continentes #4AA96C; jersey #E86F45. Ilustración plana con grano suave. Sans geométrica en negrita, texto blanco centrado arriba. Líneas discontinuas; etiquetas redondeadas.
MOTION: tranquilo, una pausa de un segundo tras cada texto. Cámara suave; etiquetas y fases con pequeño rebote; la Luna avanza a pasos.
SOUND: nana de caja de música y celesta, unos 95 BPM. Tecleo en el texto, un pop en cada etiqueta, un soplo al entrar el Sol, tic-tac de engranaje en la órbita con una campanita en cada fase, pops de madera ascendentes en la fila, un brillo en la flecha y el contorno, acorde final. Sin narración.
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How it works
Describe. Plan. Draw. Refine.
Here is what happens between your prompt and the first frame.
01
Describe the film
Say what you want in plain English: the subject, who it's for, the length, the tone. Pick 16:9, 9:16, or 1:1. Attach your screenshots or logo to show them in the film, or a photo to base a drawn character on.
02
It plans beats and shots
Before writing any code, the agent decides the shots: what each one shows, how long it holds, and where the cuts and sound hits land. The pictures and the music read the same timings, which is why the cuts land on the beat.
03
It draws, scores, and checks
It writes the code that renders every frame and the Web Audio score (music and sound effects), then reviews its own stills and a contact sheet for cropped text, collisions and blank frames before you see anything.
04
Edit, continue, export
Reply in chat to change anything; it edits the code and renders again. Share a public link, or on a paid plan export an MP4 with the soundtrack or a transparent WebM for overlays.
Two engines
Which iArt engine should you use?
Animation is one of two ways to make a video in iArt. It is the right tool when the words, data and timing must be exact, not for filmed-look footage.
| Animation | AI Video | |
|---|---|---|
| How it's made | Code renders every frame (typeset text, SVG, a canvas layer); the soundtrack is synthesized in code | A generative video model renders the footage |
| Best for | Explainers, motion graphics, illustrated films, overlays | Cinematic, filmed-look shots |
| On-screen text | Exact (typeset in code) | Drawn by the model; spelling can drift |
| Assets | None needed; your screenshots, logos, images and clips can appear too | Generated footage |
| Voiceover | AI voiceover (choose a voice) | AI voiceover |
Making an explainer with exact brand typography or data charts? See explainer videos.
Run it yourself,
or skip the setup.
The method is open source. If you live in a terminal, run it with your own coding agent. If you'd rather type a sentence in a browser, use Animation mode.
Claude Code + javascript-animation-skills
Our open-source skill pack teaches your coding agent the same method: beat grid and shot list, a drawing library, a Web Audio score, self-checks, and a render to MP4. Built and tested with Claude Opus 5.5.
- – Free and MIT-licensed; you bring your own Claude Code plan or API usage
- – Runs in Claude Code and other coding agents
- – Needs Node 18+, ffmpeg, Chrome, and playwright-core
- – The film is an HTML file you own and edit by hand
The same method, in a browser tab
Nothing to install, no terminal. Describe the film, watch it play, and change it by replying in chat.
- ✓ Runs at app.iart.ai, in the Create page's Animation tab
- ✓ Ask for any length; long films are split into scenes
- ✓ Shows your screenshots, logo or site, or draws a character from a photo
- ✓ Optional AI voiceover
- ✓ Share a public link; export an MP4 with the soundtrack, or a transparent WebM for overlays, on a paid plan
What is JavaScript animation?
JavaScript animation, in the code-rendered sense, is a film where every frame is produced by code: a function of time decides what is on screen at each moment, using typeset text, SVG shapes and canvas drawing, and the music and sound effects are synthesized with the Web Audio API. iArt's Animation mode is an AI animation generator that writes that code for you from a text prompt.
Which model does iArt's Animation mode use?
Claude Opus 5.5. The agent plans the beats and shots, writes the animation code and the score, and reviews its own stills and contact sheet before showing you the film. The open-source version of the method, javascript-animation-skills, was also built and tested with Claude Opus 5.5.
How long can a film be?
Ask for the length you want. A longer film is split into scenes in the same project, with the same look and score, and you can change any scene afterwards by replying in chat. The seed-to-tree film on this page runs 40 seconds.
Does Animation mode add voiceover or narration?
Yes. Choose a voice in the message box and the film is narrated, with the picture timed to the words. Without one, the soundtrack is music and sound effects synthesized in code.
Can I use my own images or photos?
Yes. Screenshots, logos, product photos and short screen recordings you attach appear in the film as they are; a photo of a person or a look you like is used as a reference for a drawn character or style. You can also give it your site's web address.
How much does it cost, and can I download the video?
New accounts get a $2 signup credit. $2 is enough for a film under 30 seconds. Any film can be shared with a public link. Exporting an MP4 with the soundtrack needs a paid plan (Pro is $20/month). Overlays, such as lower thirds, export as a transparent WebM instead.
Is there a free, open-source way to do this?
Yes. javascript-animation-skills (github.com/iart-ai/javascript-animation-skills, MIT) is a set of Claude Code skills that teaches your coding agent the same method and renders the film to MP4 on your machine. It needs Node 18+, ffmpeg, and Chrome. iArt's Animation mode is the same approach without the setup.
Describe the film.
The agent writes every frame.
Every frame and the score written in code. Start with the $2 signup credit; export MP4 on a paid plan.