how stacks work

a pipeline of tools, saved and reusable.

a stack is an ordered sequence of up to 10 tools wired together. each tool's output becomes the next tool's input. you drop files in at the start, hit run, and get the finished files at the end.

no intermediate steps. no manual handoffs. no uploads. everything runs inside your browser.

• compress and watermark every PDF in one run.
• strip metadata, resize, and convert a batch of images.
• center a 3D model, decimate its geometry, then optimize the GLB.
• trim or compress video, then hand off the file to a zip or hash step.
• move from PDF tables to CSV, merge sheets, or push tabular data through csv ↔ xlsx.

build it once. run it whenever you need it.

bottom of the home page. always.

open fatcousin and scroll to the very bottom of the tool index. the last row is custom stacks. click to expand. every stack you've saved on this device is listed there.

when expanded, each saved stack shows its name and a summary of its steps. hover any row to reveal three quick actions:

• fav — marks the stack as a favourite. it then appears in the favourites row at the very top of the home page, below the recents rail.
• dup — duplicates the stack and opens the copy in the editor so you can modify it without touching the original.
• edit — opens the editor for that stack.

stacks are saved in this browser's localStorage only. they do not sync across devices or browsers.

pick tools. chain them. save.

click + new stack from the home page, or go directly to /stack/new. the editor opens blank.

• add a step — with an empty stack, the picker shows the full catalog (search to narrow). after the first tool, the list filters by port compatibility so the chain stays valid.
• configure options — each step card shows that tool's settings inline: toggles, sliders, text fields. set them before you save.
• reorder — drag steps to change order.
• name it — optional. if you leave it blank, the system suggests a name from your first and last tool.
• save & open — writes to localStorage and opens the runner (new stack or returning from edit) so you can try the pipeline right away.
• pipeline status — the editor surfaces invalid chains (e.g. broken port kinds) and loose handoffs; the run button stays off until those errors are fixed.

the editor warns at 8 steps and blocks at 10 — the hard cap.

drop files. hit run. download the result.

the runner page shows a sticky flow rail at the top — the pipeline at a glance. click any chip to jump to that step on the page.

• fan-out is automatic — drop ten files, the runner processes each one and collects all outputs. you don't need to do anything differently.
• multiple outputs — get packaged into a zip automatically, plus listed individually.
• run again — after a run, hit “run again · same files” or “change input files” without leaving the page.

no page reload. no re-uploading. just run.

1305 stackable tools, 7 port kinds.

every stackable tool declares an input port and an output port (a kind like pdf, image, or file, plus whether the step expects one file or many). the count grows as new stackables land; the diagram is the type system those tools plug into.

tools that need heavy, open-ended UI — big visual editors, manual region pickers, multi-page wizards — stay on their own routes; most straight-through utilities are fair game for the registry.

a few hard lines, for good reasons.

• 10 steps per stack. enough for any real pipeline. the editor warns at 8 and blocks at 10.
• device-local only. stacks live in this browser's localStorage. they don't sync to other devices or survive a site data wipe.
• files never leave the device. every transform runs in your browser. nothing goes to a server at any point in the pipeline.
• no intermediate saving. data flows in memory from step to step. nothing is written to disk until you hit download.
• invalid pipelines don't run. unknown slugs, impossible port chains, and other hard errors keep run disabled until the editor is fixed. loose file → typed links may run but are flagged when they need human judgment.
• sharing a stack url doesn't work unless the other person has the same stack saved in their own browser. the id (e.g. /stack/abc12345) is device-local.

local. fast. yours.