Gigabytes without splitting
Memory-maps the file and builds a streaming index — opens 2–3 GB JSON in seconds without your editor crashing.
Huge-size JSON Viewer GUI · formerly Huge JSON Viewer
Open huge JSON files in a blink — for free.
A fast, native viewer for multi-gigabyte JSON on macOS and Windows. Browse, search, and convert 2–3 GB files in seconds — the free, open-source alternative to Dadroit.
macOS 11+ (Apple Silicon + Intel) · Windows 10+ · free · MIT licensed
~3 sto open a 3 GB file
~50 msto search the whole file
4 GBmax file size
20UI languages
$0free forever (MIT)
Everything you need
A large JSON viewer that treats JSON as data — not text
All the essentials of a professional JSON tool, built for gigabyte-scale files and completely free.
Instant search with RegEx
Search keys and values, plain or regular expression, with a live match count and jump-to-match that auto-expands the path.
Human-readable tree viewer
Collapsible, syntax-highlighted tree with line numbers, indent guides, type colors and child counts — browse from root to leaf.
Convert, extract & copy
Stream any node to a spreadsheet-ready CSV or to XML, pull out a subtree as JSON, or copy any key, value or path — on multi-gigabyte files with bounded memory.
Union multiple files
Open several JSON files at once as one combined tree — each labeled by filename — and search across all of them.
Tiny memory footprint
The index uses only ~1.5–2× the file size in RAM; the file itself stays as reclaimable OS page cache.
JSON Lines & NDJSON
Line-delimited and concatenated JSON logs are auto-detected and wrapped into a browsable array.
20 languages, RTL-aware
The interface ships in 20 locales, including full right-to-left support for Arabic, Urdu and Punjabi.
Private & offline
No server, no upload, no telemetry. Your JSON never leaves your computer.
Free vs. paid
BigJSON vs. Dadroit
A direct, feature-by-feature comparison. Dadroit’s free tier caps files at 50 MB and its bigger limits, union and commercial use are paid — BigJSON gives it all away.
| Feature | BigJSON | Dadroit Free | Dadroit Standard | Dadroit Advanced |
|---|---|---|---|---|
| Price | Free | Free | $98/yr | $198/yr |
| Open source (MIT) | ✓ | ✗ | ✗ | ✗ |
| Max file size | 4 GB | 50 MB | 2 GB | 1 TB |
| Open 2–3 GB JSON | ✓ | ✗ | ✓ | ✓ |
| Tree viewer | ✓ | ✓ | ✓ | ✓ |
| Search keys & values (RegEx) | ✓ | ✓ | ✓ | ✓ |
| Convert JSON → CSV / XML | ✓ | ✓ | ✓ | ✓ |
| Union multiple files | ✓ | ✗ | ✗ | ✓ |
| Commercial use | ✓ | ✗ | ✓ | ✓ |
| 20-language UI (RTL) | ✓ | ✗ | ✗ | ✗ |
| macOS + Windows | ✓ | ✓ | ✓ | ✓ |
| Offline · no telemetry | ✓ | ✓ | ✓ | ✓ |
Dadroit pricing and tiers per dadroit.com. The one thing we don’t match is literal 1 TB files (that needs an on-disk index) — everything else is free.
Under the hood
Why it doesn’t choke on gigabytes
1
Memory-map, don’t load
The file is memory-mapped and paged in on demand by the OS — never parsed into RAM-hungry objects.
2
Stream a compact index
One pass builds a flat structural index of byte offsets, so structure is known without holding the data.
3
Render only what you see
The tree is fully virtualized — only the rows on screen are materialized, so scrolling millions of rows stays smooth.
Download BigJSON
Free, open source, and native — for macOS (Apple Silicon + Intel) and Windows 10/11.
macOS 11+ or Windows 10+ · unsigned build. macOS: first launch → right-click the app → Open. Windows: if SmartScreen appears → More info → Run anyway. See the changelog.FAQ
Opening large JSON files, answered
How do I open a large JSON file on Mac?
Download BigJSON (free), then drag your .json file onto the window or press ⌘O. It memory-maps the file and builds a streaming index, so a 2–3 GB JSON opens in a few seconds — no crashing, no splitting.
Is BigJSON really free?
Yes — 100% free and open source under the MIT license, including commercial use. No paid tiers, no sign-up, no trial.
How large a JSON file can it open?
Up to 4 GB per file (and 4 GB combined for a multi-file union). The index uses roughly 1.5–2× the file size in RAM; a 16 GB machine handles 2–3 GB files comfortably.
Is it a good free alternative to Dadroit?
Yes. It covers the same essentials — a collapsible tree viewer, key and value RegEx search, JSON → CSV / XML export, and unioning multiple files — for free and open source, on macOS and Windows.
Can it convert JSON to CSV or XML?
Yes. It streams JSON to CSV (an array of objects becomes a spreadsheet) or to XML, and works on multi-gigabyte files with bounded memory.
Is my data uploaded anywhere?
No. It is 100% offline — no server, no upload, no telemetry. Your JSON never leaves your computer.
Does it work on Windows?
Yes. BigJSON runs natively on Windows 10 and 11 (64-bit), with the same tree viewer, key & value search, and JSON → CSV / XML export as the Mac build. Download the Windows installer from the releases page and, if SmartScreen appears, choose More info → Run anyway.