What Each OnePassApps Studio Accepts: File Types, Size Caps and Time Limits

I work on OnePassApps, so this is a note about our own product. Every limit below was read off the live app on 3 November 2026, not written from memory.

Seven studios, seven different sets of limits. The caps are not uniform, and they decide whether your file works at all, so here they are in one place.

Text Studio

.txt, .md, .csv and other text up to 8 MiB - or paste it straight into the input box. The input counter reads 0 / 2,000,000, and beside it the studio counts words, characters, sentences, lines and UTF-8 bytes as you type. The tabs are Clean, Case, Duplicate lines, Sort lines, Find & replace, Diff, Markdown and Base64.

Honest note: that counter and the 2,000,000 figure are two separate readouts. I did not push the input past the cap, so I cannot tell you whether the limit is counted in characters or bytes.

Data Studio

CSV, TSV, JSON or YAML - up to 20 MiB - or paste rows into the Source box. Eleven tabs: CSV Viewer, Sort / filter, Columns, Duplicates, Merge, Split and To JSON, then JSON Formatter, Validator, To CSV and YAML. The delimiter control defaults to Auto detect, and the page says why in one line: "Auto detect reads the first lines to find the separator."

File Studio

The File Studio is the odd one out, because its cap is a count and a total rather than a single size: Any files - up to 500 and 256 MiB in total. The stage shows both as live counters ("0 of 500", "0 B of 256 MiB"), and duplicate names are numbered for you, e.g. "notes (2).txt". The seven tabs are ZIP files, Unzip files, Batch rename, File hash, Find duplicates, Split file and Join parts.

Image Studio

JPEG, PNG or WebP - up to 25 MiB and 25 megapixels - two caps, not one. The tabs are Convert, Compress, Resize, Crop, Remove background, Remove metadata and Images to PDF. One conversion caveat the panel states itself: "JPEG has no transparency, so transparent areas become white."

Audio Studio

MP3, WAV, M4A, AAC, OGG, Opus, FLAC or WebM - up to 32 MiB and 45 minutes. The tabs are Convert, Compress, Trim and Extract. The panel also explains why the output format list is short: the result is "a copy in WAV, or another format this browser can encode", and the format, sample rate and channel controls only appear once "the file has been checked against this browser."

Icon Studio

SVG up to 5 MiB and 25,000 elements - the smallest cap of the seven. The tabs are SVG to PNG, PNG to ICO, Favicon pack, App icons, Resize set, Optimize SVG, Recolour SVG and Trim / padding. Your SVG is left untouched and you get "a transparent PNG at the size you set."

Colour Studio

No file to begin with: the Picker takes "HEX, RGB(A), HSL(A) or OKLCH" typed or pasted, and the arrow keys move the thumb one step, ten with Shift. Contrast, Palettes and Image follow. Swatches are kept for the visit only - the panel calls them saved swatches, and the counter reads "This visit".

The same two sentences on every studio page

Under the stage each studio prints the same pair of lines: "Nothing leaves this tab." and "Processing stays in this browser."

That is our claim, so it is worth being precise about what has been checked behind it. One tool has been traced in detail, byte by byte and request by request: hashing a file in the browser. That post is What Actually Goes Over the Network When You Hash a File in the Browser. The other six are covered by the same browser-side architecture, not by six separate traces - I would rather say that plainly than imply a proof I have not run.

The hosted apps are a different thing and I will not blur the line: NewsFlow and MovieMatcherAI do work on our servers. The Plans page draws it the same way - "Tools and Studios run in your browser and never use credits", while "new hosted work we run on our servers for your account" is what credits buy.

What I did not test

I read these caps off the live pages; I did not push each tool past its limit, so I cannot tell you what each failure message looks like. Treat the numbers as the current limits rather than a promise - they can change, and the hosted side has its own allowances on the Plans page.

If you want to try them: OnePassApps - and the written walkthroughs are on the App guides page.