All essentials

Paste a record — or drop the file — and I'll decode whatever is inside it.

Free tool

Base64 Viewer

Decode a base64 payload and look at it — a page image, a scanned exhibit, a PDF, a document. Paste the whole JSON record and every payload inside it is decoded and shown beside the fields it arrived with. Nothing is uploaded.

JSON, JSONL, data URI, or the raw string

Good to know

  • Paste a bare string, a data: URI, a JSON record, or a whole JSONL dump — every payload inside it is found.
  • The fields beside the payload — page number, file id, extraction mode — are listed with the image rather than left behind in the JSON.
  • The format is read from the bytes themselves, so an untyped or mislabelled payload is still identified.
  • A string that was cut short decodes as far as it goes, and says so rather than failing silently.

Your files stay on your machine

This tool runs entirely inside your browser tab. Nothing is uploaded, stored, or sent to a server — close the tab and every trace is gone.

These are the free ones — see the full suite

How big a file can it take?

There is no upload, so there is no upload limit — but the work happens in this tab, which means your browser’s memory is the budget. Nothing here will refuse a file for being large; a big enough one simply gets slow and, eventually, reloads the tab. The figures below are rules of thumb on a desktop browser, not enforced caps. On a phone or tablet, expect a good deal less.

  • Base64 runs about a third larger than the file it carries, and the pasted text, the decoded bytes and the preview are all held at once — comfortable to roughly 40 MB of pasted text.
  • Every payload in a dump is decoded and previewed together, so on a large JSONL file it is the number of records that binds, not the size of any one of them.

Password-protected PDFs are declined whatever their size — unlock the file first. If a run does die on a long document, splitting it into volumes and working through them one at a time is the reliable way round it.

Built on open source

The Essentials tools do their work in your browser using these open-source libraries, used under the licenses below. Each remains the copyright of its authors.

  • pdf-libMIT · creates and edits the PDFs you download
  • pdf.jsApache-2.0 · reads your PDF and renders the page previews
  • SheetJS (xlsx)Apache-2.0 · reads Excel workbooks — .xlsx, .xls, .xlsb and .ods
  • hyparquetMIT · reads Apache Parquet files
  • hyparquet-compressorsMIT · the Parquet codecs beyond Snappy — Gzip, Zstd, Brotli, LZ4
  • JSZipMIT · bundles multi-file results into one ZIP
  • LucideISC · the icons throughout these tools
  • ReactMIT · the interface itself
  • Next.jsMIT · builds and serves these pages

pdf.js ships fallback fonts contributed by Foxit Software, redistributed here as part of pdf.js. JSZip is dual-licensed; it is used here under the MIT license.