Decode base64 video
Video snippets in APIs may be base64-encoded MP4. base64app decodes, detects video formats, shows a preview player, and offers download.
How it works
- 1. Paste base64 video data above.
- 2. Click Decode.
- 3. Preview and download the video file.
Common errors
- Invalid characters — standard base64 only uses A–Z, a–z, 0–9, +, /, and = padding.
- Missing or wrong padding — length should be a multiple of 4; add = at the end if needed.
- Line breaks and spaces — email, Slack, and JSON often insert whitespace that must be stripped.
- data: URI prefix left on the string — remove data:<mime>;base64, before decoding.
- URL-safe alphabet — JWTs and some APIs use - and _ instead of + and /.
- Truncated payload — a copied string cut off mid-way cannot be fully recovered.
- Very large video — browser memory may limit huge base64 video strings.
Frequently asked questions
Which video formats work?
MP4 and other formats detected from file signatures after decode.
Can I preview video?
Yes, when the browser supports the decoded format.
File size limits?
Large payloads may fail locally above roughly 32–48 MB.
Is video uploaded?
No. All processing is client-side.
Is my data uploaded when I decode?
No. All processing runs in your browser. Nothing is uploaded, stored, or logged.
Can base64app fix corrupted base64?
Yes. Auto-repair fixes whitespace, data URI prefixes, URL-safe characters, padding, and stray characters.