from the Chadobee Creative! (Sweet!) ❤
no account · no upload — files never leave this device · free, all features
▶ Use it live · ⭐ GitHub · ❤ Donate — the "help chad take his family on a vacation for once" fund
Chadobe Keithrobat is a complete PDF editor in one HTML file. Open it in a browser, drop a PDF on it, and edit — text, images, forms, signatures, shapes, pages — then save. Nothing is ever uploaded anywhere: every byte of your document stays on your machine, processed entirely by your own browser.
The whole app is one file:
index.html. Host it anywhere (or double-click it locally). Visitors need internet access only for three open-source libraries fetched from CDNs (rendering, writing, and font embedding).
- Quick Start
- The Workspace
- The Toolbar & Keyboard Shortcuts
- Selecting Things
- Editing Text (Font Matching)
- Your Own Fonts — PC Fonts & TTF Loading
- Moving Text & Objects
- Removing Content — Content-Aware Fill
- ✨ Clean Up Area — the Smudge Eraser
- Images & Background Removal
- Shapes & Freehand Drawing
- Highlight, Underline & Strikethrough
- Fill & Sign — Forms
- The Signature Pad & the 3-Step Signature Smoother
- Page Numbers & Watermarks
- Organize Pages
- Find & Copy Text
- Saving & Exporting
- Sessions, Crash Recovery & Privacy
- Keyboard Reference Card
- Under the Hood
- Honest Limitations
- Troubleshooting & FAQ
- Credits
- Open the app at the live page, or double-click your own copy of
index.html. - Drop a PDF anywhere on the splash screen — or click the paper sheet to browse. Editing starts instantly; there is no account, no upload, no waiting.
- Click things. Click a line of text to select it. Drag a box to select a region. Every tool is one keystroke away (see §3).
- Save with the red button (or
Ctrl+S). Your edited PDF downloads immediately.
You can also open additional PDFs mid-session — they merge in as extra pages (§16).
| Region | What it does |
|---|---|
| Top bar | The CK mark, your file name, Organize (page management view), and the red Save button. |
| Toolbar | Every editing tool, each with a single-key shortcut shown on its button. |
| Page rail (left) | Live thumbnails of every page. Click to jump; an amber dot marks pages that carry edits. |
| The page | Where everything happens. Text is clickable, regions are marqueeable, objects are draggable. |
| Status bar | Current page indicator, zoom controls, the form chip (appears when a fillable form is detected), and the permanent reminder: local only — nothing uploaded. |
Pages are virtualized — only the ones on screen are rendered — so thousand-page documents scroll smoothly.
| Tool | Key | What it does |
|---|---|---|
| Select (pointer) | V |
Click text lines and objects, drag marquee boxes, move things. The default tool — most work happens here. |
| Edit text | E |
Click any text to rewrite it in place with matched font, size, and color (§5). |
| Add text | T |
Click anywhere to type new text onto the page. |
| Remove | R |
Click a text run, or drag over a region, to erase it with a content-aware patch (§8). |
| Watermark ▾ | — | Remove watermark (one click) or Add watermark… (§15). |
| Tools ▾ | — | Image, Highlight, Shapes, Organize, Find, Page numbers. Shortcuts still work. |
| Highlight | H |
Drag across text to highlight it. |
| Shapes | S |
Rectangle, ellipse, line, arrow, freehand ink — with a live options popover (§11). |
| Image | I |
Insert a picture (PNG/JPG); drag, resize, rotate, remove its background (§10). |
| Sign | — | Opens the signature pad (§14). |
Full keyboard reference in §20.
Selection is where Keithrobat does most of its thinking, so here's exactly how it decides:
- Click a text line → it selects, and the floating selection bar appears above it with actions (see below).
- Click any object you've added — text, image, shape, ink, signature — → it selects with corner handles, ready to drag or resize.
- Shapes select from their outline. An unfilled rectangle is clickable along its line (with a generous invisible hit zone), while its interior stays click-through so it never blocks the text inside it. Filled shapes select from anywhere on their body.
Click one text line, then Ctrl+click others to add them to the selection. Clicking an already-selected line toggles it off. The selection bar repositions over the whole set, and Move lifts them all as a group (§7).
The box is intent-aware, checked in priority order:
- Your own edits win. If the box covers something you added (its center inside your box, or most of it covered), that gets selected — never the invisible original text underneath it.
- Original text is selected only on meaningful overlap — grazing a line by a sliver doesn't hijack your box.
- Nothing at all? You get the area bar — the smudge eraser (§9).
Text selection bar actions: Copy · Edit (single line) · Move · Highlight · Underline · Strike · ✨ Clean area (marquee selections only — fills your exact box).
Text you have moved or removed is gone from its old spot — hidden, unclickable, invisible to marquees. It cannot be accidentally re-selected or duplicated. Undo brings it back completely.
Press E (or use the selection bar's Edit), click any text, and rewrite it. Keithrobat's editor doesn't guess at styling — it measures:
- Font matching. The embedded font's real name is read (including subset tags like
ABCDEF+Garamond-SemiBold) and mapped to the closest of the 14 standard PDF fonts, preserving weight (bold) and slant (italic). The inspector shows what matched and how confidently. - Ink & background color sampling. The actual rendered pixels are sampled, so your replacement text arrives in the original's color, on a patch matching the original's background.
- Exact baseline. The replacement is drawn on the same baseline as the original — verified to under 2px of drift at 2× rendering — so a one-word edit never makes a line jump.
- Fit-to-box. Longer replacements auto-shrink to stay inside the original's footprint instead of reflowing your document.
Every text object stays editable afterward via the inspector panel (font, size, color, alignment) whenever it's selected.
The built-in matcher maps to the closest of the 14 standard PDF fonts — good, but not your font. Keithrobat can now use the real thing:
Open any text editor (Edit or Add Text) and hit PC fonts. Your browser asks permission once, then every font installed on your computer appears in the font menu under Computer fonts — listed instantly, loaded lazily (bytes are only read when you actually pick one).
Hit +TTF and choose .ttf / .otf files — brand fonts, downloaded fonts, anything. They join the menu under Your fonts.
When a document uses a font the built-ins can't confidently match, the editor tells you — an amber warning names the font and points at PC fonts / +TTF — instead of silently defaulting. And if your loaded fonts include a match for the document's font name (subset tags like ABCDEF+MyriadPro-BoldIt are parsed, weight and slant detected), Keithrobat auto-selects your real font and says so: matched to YOUR font.
Text set in your fonts is embedded in the saved PDF as the actual font file, subsetted — only the glyphs you used, so files stay small and the text is pixel-perfect in every viewer, forever. Fonts used by your edits also persist in crash-recovery sessions.
Two honest notes: a font file carries its own weight/slant, so the B/I toggles disable for custom picks (they'd be lying); and PC-fonts enumeration is a Chromium API — Firefox/Safari users use +TTF, which works everywhere.
Three equivalent ways:
- Click a line, hit
Movein the selection bar. - Click-drag the line directly — a live ghost follows your cursor.
- Select it and press an arrow key — the first press lifts it automatically, then nudges.
Whichever you use, the same thing happens under the hood: the old spot is refilled with a content-aware patch, the original run is consumed (gone — unclickable, unduplicatable), and the text is reborn as a movable object with its matched font, sampled ink color, and exact original baseline.
Multi-select lines with Ctrl+click, hit Move, and they lift as a group: drag any member and every member travels by the identical delta; arrow keys nudge them all; Delete removes them all. One Ctrl+Z reverses the entire operation.
With anything selected:
| Keys | Movement |
|---|---|
↑ ↓ ← → |
1 pixel |
Shift + arrows |
8 pixels |
Rapid taps coalesce into a single undo step — six taps right is one Ctrl+Z, not six.
Fill patches are always background. Drag text across a previously cleaned area and the text renders — and exports — on top of the patch, no matter which was created first.
Press R, then click a text run or drag over any region. The area is erased and refilled to match its surroundings — this is the engine behind Remove, Move's patches, and Clean Up Area alike.
How it stays clean, step by step:
- Sample — a one-pixel ring is read just outside the region.
- Peel ink — the ring's samples are cluster-analyzed: foreign ink (glyphs from a neighboring line crossing the ring) forms a distinct far cluster with a measurable gap, while a legitimate gradient is a smooth continuum with no gap. Foreign clusters are peeled iteratively — solid glyphs first, then their antialiased halos.
- Loop median — the ring is filtered as the closed loop it physically is, so needle-thin artifacts (ascender/descender tips grazing the ring) cannot survive anywhere, including at edge boundaries. Uniform and gradient stretches pass through mathematically unchanged.
- Decide — if the cleaned survivors are uniform, you get a flat solid patch matching the background exactly. If they genuinely vary, you get a distance-weighted interpolated gradient patch that blends invisibly.
Practical upshot: removing white text from a dark navy slide yields flat navy, not a smeared gray band — while removing text from a real gradient banner still blends perfectly.
Important: in a Standard export, removed content is covered, not destroyed — recoverable by a determined party. For true redaction, use Flattened export (§18). The inspector reminds you of this.
Ever get a blemish, artifact, or leftover mark you just want gone? With the pointer tool, drag a box over it (slightly larger than the blemish, so the sampler sits on clean background). If the box catches nothing else, the area bar appears with three weapons:
| Button | What it does |
|---|---|
| ✨ Clean up area | Content-aware refill from the surroundings — automatically detects whether the area is part of a solid color or a gradient and patches accordingly (§8). |
| 🎨 Color swatch | Fill the box with an exact color you pick from the native color picker. |
| 💧 Eyedropper | Click it, then click any pixel on any page — the box fills with that sampled color. Crosshair cursor while armed; Esc cancels. |
If your box catches text too, no problem — the regular selection bar includes ✨ Clean area as well, and it cleans your exact box (consuming any text under it, so no ghosts).
Everything is one Ctrl+Z from undone, and the toast says so.
Press I (or the Image button) and choose a PNG/JPG. It lands centered at ~40% page width, selected and ready:
- Drag to position; corner handles resize (aspect-locked); the inspector offers rotation.
- Arrow keys nudge (1px / Shift = 8px).
Select any image and open the inspector:
- ✨ Auto — the intelligent mode. It runs the removal at nine candidate thresholds on a fast proxy, finds the elbow — the point where raising the threshold stops removing meaningfully more background but hasn't started eating your subject — applies that threshold at full resolution, and feathers the cut edge so it isn't jagged. It deliberately backs off on low-contrast subjects rather than nuking them. The toast reports the threshold it chose.
- Manual slider — for fine-tuning. After Auto runs, the slider syncs to Auto's pick, so you can nudge from a smart starting point rather than guessing from scratch.
- Restore original — one click undoes all removal, any time.
Honest note: this is smart classical segmentation (flood-fill + statistics), not a neural matting model — it excels at logos, signatures, scans, and product shots on plainish backgrounds; it won't cut a person out of a busy photo.
Press S. A popover appears under the toolbar:
| Shape | Notes |
|---|---|
| ▭ Rectangle / ◯ Ellipse | Optional fill color via the checkbox + swatch. |
| ╱ Line / ➔ Arrow | Arrowheads are computed vector geometry, not glyphs. |
| ✎ Freehand ink | Draw anything; points are captured and stored. |
Set stroke color and width (pt) in the popover before drawing; a live preview follows your drag.
After drawing:
- Shapes are selected from their outline (fat invisible hit zone — no pixel-hunting a 2pt line); filled shapes select from anywhere. Unfilled interiors stay click-through so a big annotation box never blocks the text inside it.
- Drag to move, corners to resize — line/arrow endpoints and ink points rescale correctly with the bounding box.
- The inspector edits stroke color and width after the fact, or deletes.
- Everything exports as true vector graphics (real PDF drawing operators, not rasterized pictures).
- Highlight: press
Hand drag across text, or select text and hitHighlightin the bar. - Underline / Strike: select text, hit the button. These aren't approximations — the line is drawn at each run's exact captured baseline (underline just below it, strike at mid-x-height), in the run's sampled ink color, with thickness scaled to the font size. They look native because they're placed with the same measurements the original text used.
All three are vector edits: selectable, movable, deletable, undoable.
Open a fillable PDF and the form chip lights up in the status bar: ⌨ fillable form — click a field to type.
Every AcroForm widget gets a live input overlaid exactly on it, tinted red so you can see what's fillable:
| Field type | You get |
|---|---|
| Text field | A real text input (multiline fields get a textarea), font-sized to the box. |
| Checkbox | A real checkbox. |
| Radio group | Real radios, mutually exclusive per group. |
| Dropdown | A real select with the PDF's own options. |
Your values persist with the session (§19) and never leave your machine.
Filled values are baked in permanently: the form is filled, appearances regenerated, then flattened — the values become part of the page content and the interactive fields disappear. This means the saved file shows your answers in every viewer and can't be tampered with — but also can't be re-edited as a form. The export dialog warns you ("form fields will be filled & locked") whenever this applies.
Hit Sign in the toolbar:
-
Draw your signature on the white pad — black or blue ink, your choice. Strokes are recorded as paths, not just pixels.
-
If your hand had opinions today, hit ✨ 3-Step Smoother — one click runs the full pipeline:
- Step 1 — Resample: your stroke is re-spaced evenly along its length, so drawing speed stops mattering.
- Step 2 — Tremor low-pass: a sliding averaging window collapses any wiggle shorter than the window down to your stroke's centerline. Caffeine jitter, gone.
- Step 3 — Polish: a second endpoint-pinned pass silkens what remains. Your start and end points never move; the result follows exactly the path you traced — just with a steady hand.
It's idempotent: clicking again changes nothing; drawing new ink re-arms it.
-
Place signature. The ink is auto-cropped to its bounding box, exported as a transparent PNG, and dropped on the current page as a normal image — drag it into position, resize by the corners.
-
Reuse: your signature is saved locally (in your browser only). Next time, the use saved ♻ button places it in one click.
Watermark ▾ → Add watermark…, Tools ▾ → Page numbers…, or Organize → № Numbers & watermark:
- Page numbers: pick a corner (or bottom-center), a starting number, and a point size. One number per page, right where you asked.
- Watermark: any text (default
DRAFT), rendered as real rotated vector text at 45° across every page, with an opacity slider (5–60%). It's not a pasted picture — it's genuine translucent PDF text.
Both are applied as ordinary edits: they preview live on every page, they mark pages with the amber dot, and — because they're one batch — a single Ctrl+Z removes all of them from every page at once.
Note: on pages stored with rotation, stamps follow the page's rotation.
Watermark ▾ → Remove watermark, or click watermark removal on the splash screen to open a file and strip it on load. It takes the mark out of the PDF itself, not just covers it:
/Watermarkannotations, and stamp annotations repeated across pages- marked content tagged as a watermark artifact (Word, Acrobat, most office exports)
- optional-content layers named watermark / draft / confidential / sample
- diagonal text, and translucent text or images repeated on most pages
- watermarks this app added
Ctrl+Z puts the original file back exactly. If nothing is found, it says so.
No OCR. A watermark baked into a scanned page image is just pixels. Use Remove (R), drag over it, and save Flattened.
The Organize button opens a grid of every page:
| Action | How |
|---|---|
| Reorder | Drag cards. |
| Rotate | Per-page ↻ button, or ↻ Rotate all for the whole document (scanned-sideways rescue). |
| Duplicate / Delete | Per-card buttons. |
| Extract | Save any single page as its own PDF. |
| + Blank page | Insert an empty page (letter-sized). |
| Merge | Add another PDF's pages into this document. |
| № Numbers & watermark | See §15. |
Everything here is undoable, and the rail + amber dots stay in sync.
Ctrl+Fopens Find: type, and every match across every page is counted and highlighted;Enter/arrows walk between hits, scrolling pages into view.- copy all text (button in the find bar) extracts the entire document's text to your clipboard in one click — the feature every other PDF tool buries.
Ctrl+S or the red Save button:
| Option | Details |
|---|---|
| File name | Whatever you like; .pdf is appended. |
| Pages | all, or a range like 1-3,7. Reversed ranges are auto-corrected, out-of-bounds pages clamp, and nonsense gets a friendly error instead of a broken file. |
| Standard | Editable-style output; removed content is covered by patches (smaller file, faster). |
| Flattened | Every page rasterized — removals become unrecoverable. Use this for true redaction. |
If you've filled form fields, the dialog reminds you they'll be filled & locked (§13). Every export is scrubbed: author, title, creator, dates, XMP and edit history are stripped. The only thing left is Producer: Chadobe Keithrobat Pro CK, because branding matters.
- Local only, always. No account, no server, no telemetry. A Content-Security-Policy blocks the page from connecting anywhere, and all four library files (including the pdf.js worker) are pinned with SRI hashes, so a tampered CDN file refuses to run. The status bar says local only — nothing uploaded because it's permanently true.
- Crash recovery. Your document, edits, and form values are checkpointed to your browser's local IndexedDB. Close the tab accidentally or crash — reopen the app and you're offered your session back.
- Saved signature lives in the same local store; it never travels anywhere.
- Clearing your browser's site data erases all of the above — which is exactly the control you should have.
| Keys | Action |
|---|---|
V / E / T / R / H / S / I |
Select · Edit text · Add text · Remove · Highlight · Shapes · Image |
Ctrl+Z / Ctrl+Y |
Undo / Redo |
Ctrl+F |
Find |
Ctrl+S |
Save / Export |
Ctrl+O |
Open a PDF |
↑ ↓ ← → |
Nudge selection 1px (auto-lifts selected original text) |
Shift + arrows |
Nudge 8px |
Delete |
Delete selection (whole group if grouped) |
Ctrl/⌘/Shift + click |
Add/remove text lines to a multi-selection |
Esc |
Close bars, editors, modals; cancel eyedropper |
For the curious:
- Architecture: one HTML file containing a pure computational core (font matching, geometry, fill math, form filling, page ops, smoothing) plus the UI layers. The core is dependency-injected and runs headless — which is how the test suite drives it.
- Rendering by pdf.js; writing by pdf-lib. Both loaded from cdnjs; everything else is hand-rolled.
- The consumption model: moved/removed text is tracked on the fill edit that replaced it, not in a side flag — so undo/redo restores it for free, by construction.
- The z-order rule: fills are background, everything else stacks above, relative order preserved within each class — applied identically in preview, pixel sampling, and export so all three always agree.
- Testing: 116 automated tests across three suites, run with
npm test. A pure engine suite (90 tests) drives the core directly in Node. A pixel-verification suite (12 tests) exports real PDFs, rasterizes them with poppler, and reads the pixels back, so the writer and the reader can't share a bug. An integration suite (14 tests) boots the actual shipped file in real Chrome and drives it through real mouse and keyboard events — including an assertion that nothing leaves the browser during export.npm run test:mutatebreaks the app four different ways and fails unless the tests notice each one. The suites readindex.htmlitself rather than a copy, so there is no second source of truth to drift. Seetests/README.md.
We'd rather tell you than have you find out:
- Automatic matching maps to the closest standard font when you haven't loaded your own — it can't reconstruct a font it doesn't have. The fix is built in: load the real font via PC fonts or +TTF (§6) and it's embedded exactly. The one true impossibility: extracting a subsetted embedded font out of the PDF for reuse — subsets are legally and technically incomplete.
- Standard export covers, Flattened destroys. Choose accordingly for sensitive redactions.
- Rotated pages: text edits on them are rasterized (they render correctly, but as image rather than vector text).
- Filled forms flatten on save — by design, values are permanent and fields stop being interactive.
- Background removal is statistical, not neural — superb on logos/scans/signatures, not a portrait cutter.
- No OCR (scanned-image PDFs have no text layer to edit) and no password encryption on export — both would require dependencies that don't fit the single-file promise.
The splash never loads a file / rendering fails. The three CDN libraries need internet on first load. Offline hosting? Ask for the fully-inlined build (~1MB heavier).
I moved text and there's a faint mark left. Draw a box over it → ✨ Clean up area. See §9.
A patch grabbed the wrong color. Undo, then use the eyedropper to sample the exact color you want, or the swatch to specify one.
I can't select my shape. Click its outline (unfilled shapes keep their interior click-through on purpose). Filled shapes select from anywhere.
Find locates text I already removed. Correct — in Standard mode the text still exists underneath its patch. Flattened export makes removals real.
My form won't stay interactive after saving. By design (§13); values are baked and locked.
Where's my data stored? Your browser's IndexedDB, on your machine, full stop.
Chadobe Keithrobat Pro CK
A free, browser-based .PDF editor
text editing | move | font matching | watermark removal | fill & sign — and more!
from the CHADOBEE CREATIVE! (Sweet!) ❤
Free for personal use, for learning, for embedding the engine in your own software, for
building your own local-first PDF editor, and for anything else that isn't selling this
product. If you want to package it up and sell it, come talk to me and we'll work out a
cut. Plain English, in LICENSE.md.