Capture JSON Screenshot Generator Online
Capture JSON Screenshot and Render pretty-printed JSON as a syntax-highlighted PNG screenshot - dark or light theme, adjustable width and font size.
Turn any JSON blob into a syntax-highlighted PNG image — perfect for blog posts, bug reports, or sharing on social media. Pick a dark or light theme, set width and font size, and download the result. Everything happens in your browser.
How to Use Capture JSON Screenshot Generator Online
- Paste your JSON. Any valid JSON value - object, array, or primitive. The tool reformats it with 2-space indentation before rendering, so ugly minified JSON becomes readable immediately.
- Pick a theme. Dark matches VS Code dark+ with blue keys and orange strings. Light matches GitHub with navy keys and green strings. Change any time to re-render.
- Tune width and font size. Width between 320px (mobile) and 2000px (billboard). Font size between 10 and 20 px. Height is calculated automatically from the number of lines.
- Watch the live preview. The preview re-renders 200 ms after you stop typing or moving the sliders - no need to click Render for every change.
- Press Ctrl/Cmd+Enter for an explicit render. Useful when you paste a very long JSON and want to skip the debounce.
- Read the stats line. Line count, input byte size, canvas dimensions, PNG byte size, theme, and render time in milliseconds.
- Copy or download. Copy tries to place the PNG blob directly on your clipboard (Chrome/Edge/Safari support this) and falls back to copying the data URL as text. Download saves a timestamped .png.
Frequently Asked Questions
What does this tool do?
It takes JSON, pretty-prints it, and paints it onto a canvas with syntax colouring, then exports a PNG. Useful for embedding JSON in blog posts, bug reports, Slack, or social threads where copy-paste would be ugly.
How does the syntax highlighting work?
A small line-level tokeniser detects keys, strings, numbers, booleans, and null – each gets its own colour from the selected theme. It is deliberately simple (not a full JSON parser) so rendering stays fast.
What themes are available?
Two: Dark (VS Code dark+: #1e1e1e background, blue keys, orange strings) and Light (GitHub-style: white background, navy keys, green strings). Change between renders to see which reads best for your content.
Can I paste any JSON?
Yes – any valid JSON object, array, or primitive. Invalid JSON shows an inline error with the parser’s position hint so you can fix the typo quickly. The tool does not sanitize or mutate your values.
Is there a size limit?
The canvas height is capped at 8,000 px. If your JSON exceeds that, the image clips at the last visible line and the stats line flags “(clipped)”. Reduce the font size or split the JSON into two screenshots.
Does “Copy PNG” place an actual image on my clipboard?
Yes when the browser supports ClipboardItem (Chrome/Edge/Safari) and the page is served over HTTPS. If unsupported, the tool copies the PNG data-URL as text – you can still paste it into an <img src> or address bar.
Is my data secure?
Yes – 100% client-side. The JSON never leaves your browser. There is no network request of any kind once the page has loaded.
Is this tool free and offline-capable?
Yes on both counts. Free with no sign-up or usage caps, and once the page loads the tool keeps working without a network connection.
Does it preserve my JSON’s original formatting?
No – the tool parses and re-stringifies with 2-space indentation to guarantee consistent output. If you need a specific indent style, format your JSON first and the tool will still render it, but it re-prints from the parsed tree.
What about transparency?
The PNG has a solid theme background colour (no transparent pixels). If you need a transparent backdrop, open the PNG in a raster editor and remove the background manually.