# Flipline > A few drawings. A little life. Make a flipbook in your browser. Flipline is a free drawing, pixel-art and animation studio that runs on your device. Sketch poses across layers, compare onion skins and play drawings with adjustable holds. Pixel Studio adds indexed sprite drawing, palettes and live loops; Retro Lab converts photos with color development, dithering and shared batch recipes. Transform marks, let Flipline draw the inbetweens between two key poses, export compact GIFs, videos, PNG sequences, sprite atlases or storyboards, and keep editable project files for your next idea. Flipline (Drawing, pixel art & animation) is a premium app of usefulweb.app (https://usefulweb.app/): a full program that runs in the browser. Its engine is deterministic and the same functions are exposed as tools, so an agent can compute exactly what the app shows. ## Use it - Landing page: https://flipline.usefulweb.app/ - Workspace (browser app): https://flipline.usefulweb.app/app - open a project with https://flipline.usefulweb.app/app#project= or a template with https://flipline.usefulweb.app/app#template= - Project file format (JSON Schema): https://flipline.usefulweb.app/project.schema.json - Tutorials: https://flipline.usefulweb.app/tutorials - JSON API: POST https://flipline.usefulweb.app/api/v1/tools//calculate (catalog: https://flipline.usefulweb.app/api/v1/tools) - OpenAPI: https://flipline.usefulweb.app/openapi.json - MCP (Streamable HTTP): https://flipline.usefulweb.app/mcp ## Engine tools - [Animation Exposure Sheet](https://fliplineexposuresheet.usefulweb.app/): Turn drawing holds into a precise animation timing sheet. API: POST https://flipline.usefulweb.app/api/v1/tools/flipline-exposure-sheet/calculate · MCP tool `flipline_exposure_sheet` - [Sprite Sheet Layout Planner](https://fliplinespritesheet.usefulweb.app/): Plan an animation atlas with exact frame rectangles and padding. API: POST https://flipline.usefulweb.app/api/v1/tools/flipline-sprite-sheet/calculate · MCP tool `flipline_sprite_sheet` - [Animation Motion Study Generator](https://fliplinemotionstudy.usefulweb.app/): Generate an editable flipbook to compare animation easing curves. API: POST https://flipline.usefulweb.app/api/v1/tools/flipline-motion-study/calculate · MCP tool `flipline_motion_study` - [Pixel Art Image Converter](https://fliplinepixelquantizer.usefulweb.app/): Convert images into pixel art with palettes, dithering and retro effects. API: POST https://flipline.usefulweb.app/api/v1/tools/flipline-pixel-quantizer/calculate · MCP tool `flipline_pixel_quantizer` - [Pixel Grid Transform](https://fliplinepixeltransform.usefulweb.app/): Flip, rotate or shift an indexed pixel sprite without blur. API: POST https://flipline.usefulweb.app/api/v1/tools/flipline-pixel-transform/calculate · MCP tool `flipline_pixel_transform` - [Pixel Palette Format Converter](https://fliplinepaletteconverter.usefulweb.app/): Convert HEX, GIMP GPL and JASC-PAL palettes without changing color order. API: POST https://flipline.usefulweb.app/api/v1/tools/flipline-palette-converter/calculate · MCP tool `flipline_palette_converter` - [Retro Pixel Art Batch Processor](https://fliplineretrobatch.usefulweb.app/): Apply one retro palette and effect recipe to a ZIP of images. API: POST https://flipline.usefulweb.app/api/v1/tools/flipline-retro-batch/calculate · MCP tool `flipline_retro_batch` ## Formats - Import: Flipline project (.flipline.json), PNG, JPEG, WebP, Uniform PNG/JPEG/WebP sprite sheets, Pixel sprite (.flipline-pixels.json), Retro recipe (.flipline-retro.json), HEX, GIMP GPL or JASC-PAL text palette - Export: Retro recipe (.flipline-retro.json), HEX, GPL and JASC-PAL palettes, Retro PNG and editable asset batch ZIP, Pixel sprite (.flipline-pixels.json), Flipline project (.flipline.json), Animated GIF (adaptive palette, optional transparency), Video (WebM, or MP4 where supported), PNG sequence + timing JSON (ZIP), Sprite sheet + atlas JSON (ZIP), Current drawing PNG, SVG with embedded PNG, Print / PDF via browser, Storyboard print / PDF ## Limits - Retro Lab: eight images, 4 MB and 2 MP per image, 8 MP decoded in total, 128 native pixels per side and 1–8 integer PNG scaling. Recipes contain settings only. - Retro conversion uses binary alpha, nearest RGB palette matching and manual controls. No video conversion, AI stylization, binary palette formats or PixaTool preset import. - Pixel Studio: 1–128 pixels per side, 24 frames, four layers, 32 palette colors and 524288 stored cel pixels. PNG/JPEG/WebP imports are limited to 4 MB and 2 MP; editable pixel files to 4 MB. Pixel Studio edits indexed pixels; Retro Lab adds dithering before import. - Pixel GIFs use binary transparency and at most 12 million total frame pixels. No animated GIF import, .piskel import, arbitrary selections or tile-map editing. - Up to 24 drawings, four layers, 2 MP per canvas and 1600 px per side. Holds are 1–10 ticks at 1–30 FPS. - Project limits: 50000 points, 2000 marks and approximately 6 MB of embedded image data. Imports are limited to 16 MB project files or 3 MB per image. - Drawing board GIFs use one adaptive palette of up to 256 colors without dithering, binary transparency, at most 24 million total frame pixels and 10 ms timing units. Video export records in real time (up to 60 seconds, no audio) and depends on browser MediaRecorder support. - No audio timeline, camera animation, pressure-sensitive brushes or multi-mark selection. Inbetweens interpolate paired marks only; they do not redraw changing shapes. - Scaling is uniform around the mark center and keeps stroke width; there is no skew or per-point editing. Selection uses the mark bounds. Canvas resizing scales all normalized drawing positions. - Browser storage can be cleared or evicted. Download an editable project as a durable backup.