Base64 Data URI Decoder
Paste any data URI to inspect its MIME type, encoding, payload size, and decoded content.
Last updated: October 12, 2026
Try with a Sample:
URI Anatomy Report
Paste a data URI on the left to break it into scheme, MIME type, parameters, encoding, and payload — with a decoded preview when possible.
Base64 Data URI Decoder
Take any data URI apart with our Base64 Data URI Decoder. Paste a complete data:... URI and get a full anatomy report: scheme, MIME type, parameters such as charset, encoding method, payload character count, and true decoded byte size. Textual payloads including plain text, HTML, JSON, and SVG are decoded into a readable preview, images render as an instant thumbnail, and any payload can be copied or downloaded as a reconstructed file. Malformed URIs get precise structural errors, from a missing data: scheme to an absent comma or an invalid MIME type. Everything runs instantly and locally in your browser.
Why This Tool Exists
What makes this useful — and why I built it this way.
Total Transparency: Every component of the URI laid out clearly.
Instant Previews: Text decoded to readable form, images rendered.
Clean Extraction: Payload copying without manual comma-splitting.
Exact Errors: Know precisely which structural rule failed.
Local Processing: URIs never leave your browser.
When You'd Use This
Real situations where this tool saves the day.
Frontend Debugging: Find why an embedded asset fails to render.
Email Forensics: Inspect inline data URIs from raw messages.
Security Review: See exactly what a pasted data URI contains.
Content Auditing: Measure embedded asset weight in pages.
Learning: Understand data URI structure piece by piece.
Using Base64 Data URI Decoder
It's straightforward — here's how it works.
Paste a complete data:... URI into the input box.
The anatomy report builds automatically as you paste.
Read textual payloads or preview images inline.
Copy the payload or download the decoded file.
Questions People Ask
Honest answers about how this works.
What is the difference between this and Base64 to File?
This tool inspects and explains: it breaks the URI into labeled components, previews text and images inline, and validates structure. Base64 to File is the downloader: it rebuilds any Base64 payload into a named file with format detection.
Does my data URI leave the browser?
No. Parsing, decoding, previews, and downloads all happen locally in your browser. Nothing is uploaded, logged, or stored.
Which payloads get a text preview?
Text types, JSON, and SVG are decoded as UTF-8 and shown up to 2000 characters. Binary payloads show size stats instead, with download available for the full content.
Why does it say my URI is malformed?
The most common causes are a missing data: prefix, no comma between metadata and payload, an empty payload, or a MIME type that is not in type/subtype form. The error message names the exact problem.
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