Find and replace is one of those jobs that quietly sends your file to somebody else's server. You paste a config file, a customer list, or a draft with a name in it, and the words come back changed - because the text was uploaded on the way.

Text Studio does the same job inside the tab you already have open. I work on OnePassApps, the team behind the app. Find and replace is one of eight tools on the Text Studio page.

This post is about the mechanics rather than the pitch: what the panel actually offers, what its defaults do, and how to read the result so you know the replacement really happened.

The panel, in three steps

The Find & replace tab sits between Sort lines and Diff in the tab row - eight tools in total: Clean, Case, Duplicate lines, Sort lines, Find & replace, Diff, Markdown and Base64.

  • 01 Input text - a textarea with a character counter, plus live stats for words, characters, sentences, lines and UTF-8 bytes. The counter reads against a 2,000,000 character ceiling.
  • 02 Find and replace - a Find box, a Replace with box, and two checkboxes: Regular expression and Case-sensitive.
  • 03 Result - the panel copy reads "Replaced text shows on the stage, ready to copy, download or use as the new input." and "Nothing leaves this tab." The action button is Replace all.

Files come in the same way as text is pasted: the drop area accepts ".txt, .md, .csv and other text up to 8 MiB", and the page adds the reassuring line "Processing stays in this browser."

The defaults are the part people get wrong

When I opened the tab in the browser, Case-sensitive was already ticked and Regular expression was not. That is the opposite of the usual find-and-replace convention, where matching is case-insensitive until you ask otherwise.

It matters, because with the default settings on, searching for browser will not touch Browser. If you are sweeping a list of product names or API keys, that is the difference between a clean run and one that silently misses half the lines.

Four runs, and what came back

I ran the tool on the live page with real text, reading the result panel each time.

1. Plain replace, defaults (case-sensitive on). Input: "The Studio runs in the browser, so the browser never sends your text to a server." Find browser, replace with tab. Result: "The Studio runs in the tab, so the tab never sends your text to a server." Both lowercase matches were replaced, and the stage reported "73 characters · 1 line" under the heading Replaced text.

2. Case-sensitive off. Input: "The browser is a tab. The Browser tab runs locally." Find browser, replace with TAB. Result: "The TAB is a tab. The TAB tab runs locally." With the box unticked, the capitalised occurrence matched too - that is the run that proves the checkbox is doing something.

3. Regular expression on. Input: "one two three". Find \s+, replace with a single space. Result: "one two three". The stage reported "13 characters · 1 line".

4. Nothing matched. Input: "nothing to match here". Find zzz, replace with x. The text came back unchanged, and the stage still said "Replacement complete."

Run 4 is the one to remember. The panel reports "Replacement complete." whether it changed one character or none, so treat that line as "the operation finished", not "your text was modified". If you need certainty, read the Replaced text block itself - the stage shows the full string, not a diff, so compare it against your input.

Two smaller behaviours I hit while testing:

  • Pressing Replace all with an empty Find field does not run. The panel answers "Enter the text to find." instead of touching your text.
  • Switching Regular expression on adds a warning line: "Complex expressions stop automatically if they take too long." So a runaway pattern is cut off rather than freezing the tab, and you get the text back unmodified.

Getting the result out

The stage offers three ways to take the result: Use as input (feed it straight back in as the new input for another pass), Download .txt, and Copy. There is also a Text result label above the block, and the stage reports the new size - character count and line count - so a replacement that unexpectedly halves or doubles the text is visible before you use it.

Why it stays in the tab

The claim is printed on the page rather than buried in a privacy policy: "Nothing leaves this tab." and "Processing stays in this browser." For text that carries names, tokens or unreleased drafts, that is the difference between a tool you can use on real material and one you use on a sample.

What it costs

The plan block on the same page reads FREE PROMOTIONAL PERIOD, Standard is free right now, $0 / month, and "100,000 credits every 30 days · No end date set · No card required", with a line saying "No automatic paid subscription. Existing paid subscriptions keep their terms." No card, no signup to paste text in.

The other seven studios - image, audio, file, data, icon and colour - follow the same model, and each tool has a guide page if you want the longer version: the OnePassApps guides.

Again, I work on OnePassApps - Find and replace is one of the tools we ship in Text Studio, and every result above came out of the live page in this browser tab.