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JSON Size Analyzer

raw · minified · gzip · brotli · heaviest keys · duplicate strings

See where the bytes go. Compare raw, minified, gzip, and (estimated) brotli sizes. The heaviest-keys table lists the top 20 byte hogs; the duplicate-strings card finds strings that repeat 3+ times (good gzip candidates).

Top 20 heaviest paths

    Duplicate strings (≥3×)

      Paste JSON.

      How to analyse

      1. Paste or drop your JSON.
      2. The Sizes card shows: Raw bytes, Minified bytes, Gzip bytes (level 6), Brotli bytes (level 4). Each with percent vs raw.
      3. The Heaviest keys table lists the top 20 paths by byte cost (with depth + sample value). Click any row to highlight that subtree in the tree view.
      4. The Duplicate strings card lists strings that repeat ≥ 3 times — these compress well but bloat your raw size; consider extracting them.
      5. Depth histogram shows how nested the document is.

      FAQ

      Is the brotli figure exact?

      It's an estimate (~85% of gzip in practice). For exact brotli, run brotli -q 4 on the file or use a server-side tool. Gzip is computed exactly by the in-browser library.

      What does a low gzip ratio tell me?

      That your JSON is mostly unique strings (e.g. UUIDs, free-text). Reducing duplication won't help — reduce the data itself.

      Will it work offline?

      Yes — uses pako for gzip, cached after first load.