JSON Viewer — Pretty-Print and Explore JSON
Pretty-print JSON with two-space indentation for easier reading and debugging.
How it works
- 1Paste or type your text in the input field
- 2Click "Format JSON" — processing happens in your browser
- 3Copy the result or download as a text file
What to do next
About JSON Viewer / Formatter
JSON Viewer / Formatter is part of a collection of single-purpose developer utility tools. Pretty-print JSON with two-space indentation for easier reading and debugging. Each tool is intentionally narrow — it does one thing well rather than offering many overlapping features — which makes the common path predictable and the result easy to verify before you download or copy it.
JSON Viewer / Formatter runs on standard browser APIs — an open-source, well-audited engine that performs the developer utility natively in the browser. It accepts the formats listed in the upload area and produces output that opens in any standard developer viewer. Per-run input is capped at 0 MB.
JSON Viewer / Formatter works well as a bookmarked utility you reach for when you need it. The first visit shows you what the tool does; the second is when you realise it is a low-friction option for the task and worth keeping in your tab list.
The execution model is straightforward: your file is bytes in the tab's memory, the engine reads those bytes, computes the result, and hands the result back to the browser. The transformation happens locally, which is why the tool keeps working when your network connection drops mid-job and why it produces the same result every run for the same input.
On limits: 0 MB per file is the ceiling. Output formats and quality settings are listed in the controls panel above, and they apply to every run.
JSON Viewer / Formatter fits naturally next to several adjacent tools. Common companions include JSON Minifier, JSON Validator, JSON Flattener, and JSON Diff Tool — combine them when the job needs more than one transformation. After running JSON Viewer / Formatter, many users move on to JSON Minifier and JSON Validator. Each tool is a separate page so you can compose the exact pipeline you need.
JSON Viewer / Formatter is shaped around the recurring needs of two audiences: students learning new languages, who use it as a quick utility between bigger tools, and devops engineers crafting one-liners, who use it as their primary way of getting the job done. Both groups get the same defaults and the same speed.
Output handling is intentionally boring: JSON Viewer / Formatter produces a single output file and triggers your browser's standard "save" behaviour. If you have a default download folder configured, that is where it will land. There is no Favtoo-side history of jobs you have run.
JSON Viewer / Formatter is honest about scope: it handles a single, well-defined developer utility step. Specialist edge-case work — uncommon formats, very large inputs, or pipelines that need scripting — is what dedicated desktop apps are for. This page handles the common case quickly.
JSON Viewer / Formatter is structured around the idea that a useful tool should be its own page. Open the page, do the work, close the tab — the page is the entire product. There is no onboarding flow because there is nothing to onboard into.
Useful patterns when working with JSON Viewer / Formatter: keep the input file open in another tab so you can compare against the result; give the output file a descriptive name when saving so you can find it later (the default name is sensible but generic); and treat each run as independent — the tool has no concept of "history", which means you cannot accidentally pollute one job with leftovers from another.
JSON Viewer / Formatter fits the gap where opening a desktop app feels heavy and writing a script feels overkill. The page handles the common developer utility task with sensible defaults so a single visit usually completes the job; for highly specialised work, a dedicated desktop application can offer more knobs to turn.
For most failure modes, refreshing the page and re-running the job is enough — the engine has no persistent state to corrupt. If the same input fails twice in a row, the input itself is most likely the problem (a truncated file, an unexpected variant of the format, or a stream the engine does not recognise).
That is essentially everything JSON Viewer / Formatter does and how it does it. Open the tool above, drop in your input, and the work happens in the page. If you find yourself reaching for it often, bookmark the page — it loads quickly on subsequent visits, and your most-recent settings are remembered for the rest of the session.
How it works
- 1Land on the JSON Viewer / Formatter page. The tool is ready to use the moment the page renders.
- 2Select the developer file you want to process — drag-and-drop and the file picker both work.
- 3Tweak the controls if the defaults are not quite right for your input. The options are kept short and labelled in plain language.
- 4Click to start the job. The engine (standard browser APIs) processes the input in the page; you can watch the progress indicator until it completes.
- 5Grab the output as soon as the run completes. You can also copy the result instead of downloading if the next tool in your workflow accepts pasted input.
- 6Re-run with different settings as often as you want. Each run produces a fresh output and the original file on disk is never modified.
Common use cases
- Validate a config blob before pushing to staging using JSON Viewer / Formatter.
- Decode a token to confirm its claims during a debugging session.
- Encode binary content for transport in a JSON body.
- Hash a string for a quick reproducibility check.
- Format a noisy log line into something a teammate can read.
- Inspect a payload during local development without writing a script.
- Pretty-print a minified blob during incident triage.
- Generate boilerplate from a single specification line.
- Compare two API responses to spot a regression.
FAQ
How is JSON formatted?
The tool parses JSON and serializes it with JSON.stringify and a two-space indent so nested structures are easy to scan.
Does formatting reorder keys?
Most modern engines preserve insertion order for object keys when round-tripping through JSON.parse and JSON.stringify.
Is my JSON stored online?
No — formatting happens only in your browser; nothing is uploaded or logged by this tool.
Can I collapse sections?
This viewer outputs indented text only. For collapsible trees, paste output into your editor or a dedicated JSON explorer.
What if formatting fails?
Invalid JSON cannot be pretty-printed; fix syntax errors reported by the parser first.
Does it support large files?
Large inputs may be slow or memory-heavy depending on your device; split very large payloads if needed.
Which browsers are supported by JSON Viewer / Formatter?
JSON Viewer / Formatter works in any modern browser released in the last few years — Chrome, Edge, Firefox, Safari, Brave, Arc and the major Chromium derivatives are all supported. The underlying engine relies on widely-supported web APIs, so there is nothing exotic to install. If you are on a very old browser version and the tool fails to load, updating to the latest release of your preferred browser is the only fix needed.
What does the error message in JSON Viewer / Formatter mean?
Failures usually fall into one of three buckets: the input is in an unsupported format, the input is over the size cap, or the input is structurally malformed (a truncated download, a partial export, or a stream the engine does not recognise). The first two are easy to confirm — check that your file is in a supported format and that it is below 0 MB. For the third, opening the file in its native viewer first is the fastest way to confirm the source is intact.
Where does my file actually go when I use JSON Viewer / Formatter?
Your file is processed inside your browser by standard browser APIs. The engine reads the file's bytes from your tab's memory, computes the result, and writes the result back into the tab. You can confirm what the page does by opening developer tools and watching the Network tab during a run — the requests you see are for the tool's static assets only.
Can I use JSON Viewer / Formatter on iOS or Android?
JSON Viewer / Formatter runs in any modern mobile browser — Safari, Chrome, Firefox and the in-app browsers in most messaging apps all support the underlying APIs. Performance depends on the device: a recent phone handles typical inputs nearly as fast as a laptop, while older devices may take a few seconds longer near the 0 MB ceiling. The interface lays out cleanly on small screens, so you do not need to pinch-zoom to see the controls.
Will JSON Viewer / Formatter keep working in a year?
JSON Viewer / Formatter is updated whenever the underlying engine releases an improvement or a bug fix. Because the tool is delivered as a static page, every visit fetches the latest version automatically — there is no "version" to manage on your end. If a particular release ever changes default behaviour, the change is documented on Favtoo's changelog so you can confirm what shifted.
Do I need to install anything to use JSON Viewer / Formatter?
No installation is needed. JSON Viewer / Formatter runs as a normal web page, with no browser extension, no native helper, and no separate desktop client to download. That is partly a privacy choice — extensions can request broad permissions, while a regular page is sandboxed by default — and partly a convenience one: you can use JSON Viewer / Formatter on any computer you have temporary access to without leaving anything installed on it.
What does JSON Viewer / Formatter do that command-line tools do not?
Desktop apps usually have more advanced features but require installation, maintenance and (often) a licence. Paid online tools are convenient but route your file through their servers and gate downloads behind accounts. JSON Viewer / Formatter sits in between: free, instant, and private, but intentionally narrow in scope. For one-off jobs and the common developer utility operations, it is usually the lowest-friction choice; for highly specialised work, a dedicated app is still the right answer.