Find And Replace

Tool Overview

This find and replace tool searches your text for one or more patterns and replaces them with new text. You enter the text to search in, add find and replace pairs, and choose options such as case sensitive or whole word. The tool finds all matches, lets you preview and choose which ones to replace, then applies the replacements. You can use plain text or regex patterns.

People often need to change the same word or phrase in many places. Doing it by hand is slow and easy to miss a spot. This tool solves that by finding every match, showing you where they are, and letting you replace them in one go. You can turn off some matches before applying so only the ones you want are changed.

The tool is for anyone who edits text. Writers use it to fix a term or name. Developers use it to change a variable or string in code. You do not need technical skills for basic find and replace. For regex you need to know pattern syntax. An optional AI feature suggests related search terms; the main find and replace does not depend on it.

Background & Concept Explanation

Find and replace means searching a piece of text for a pattern and swapping each match with another string. The pattern can be a literal phrase or a regular expression. Regular expressions let you match many variations (for example any digit or any word) in one pattern. The tool runs the search and collects every match. You can then replace all of them or only the ones you select. Replacing is done from the end of the text toward the start so that positions do not shift and the right pieces are changed. A related operation involves comparing text content as part of a similar workflow.

Find and replace is used in many places. Documents are updated when a name or date changes. Code is refactored when a function or variable is renamed. Lists or data are cleaned when a label or format is standardized. Without a tool you would have to search by eye or use a separate editor. This tool runs in your browser so you paste the text, set the find and replace pairs, and apply.

People struggle when they do it by hand. They miss occurrences. They change the wrong place. They need to match only whole words or only a certain case. This tool finds every match, shows them in context, and lets you choose options: match case, whole word, or regex. You can add more than one find and replace pair so several patterns are handled in one go. You can preview which text will change and uncheck matches you do not want to replace.

The tool does not keep an undo history. Once you apply, the text is updated. If you need to undo, copy the text before applying or do not apply until you are sure. For adjacent tasks, comparing JSON structures addresses a complementary step.

Key Features

• You paste or type the text to search in. The input has a character limit of 100000 characters. A counter shows how many characters are left; when you are close to the limit it turns red. This keeps the tool responsive and avoids overload.
• You add one or more find and replace pairs. Each pair has a find field and a replace field. You type what to search for and what to put in its place. You can add up to 20 pairs. The tool runs all of them and collects every match from every pair. You can remove a pair if there is more than one. This lets you do several replacements in one pass or use one replace value for multiple find patterns.
• Matches are found automatically when you change the text, the pairs, or the options. For each pair with a non-empty find string, the tool builds a search pattern. If regex is off, special regex characters in the find string are escaped so the search is literal. If whole word is on and regex is off, the pattern is wrapped so only whole words match. If regex is on, the find string is used as the regex pattern. The tool runs the pattern with a global flag and optionally a case-insensitive flag. It collects each match with its position, length, the matched text, the replacement text for that pair, and a short context before and after. Invalid regex shows an error message. Matches are sorted by position. There is a limit on how many matches are collected so the tool does not freeze on huge texts.
• Three options change how the search works. Match case: when on, uppercase and lowercase must match; when off, case is ignored. Whole word: when on and regex is off, the find string must match a whole word (not part of a longer word). Regex: when on, the find string is treated as a regular expression so you can use patterns. These options apply to all pairs. This gives you control over what counts as a match.
• The preview pane shows your text with every match highlighted. Selected matches are highlighted in one color; deselected matches in another. So you see where each match is before you apply. You can switch to review mode to see a list of matches with context and replacement text and check or uncheck each one. This lets you skip matches you do not want to replace.
• Review mode shows each match as a row. You see the position, a short context before the match, the matched text, an arrow, the replacement text, and a short context after. Each row has a checkbox. Checked matches are included when you apply; unchecked ones are left unchanged. You can toggle the checkbox to include or exclude that match. This lets you replace only some of the matches.
• Apply runs the replacement for all selected matches. The tool sorts selected matches by position from high to low so that replacing from the end first does not change the positions of earlier matches. It then replaces each selected match with its replacement string and updates the text. A message shows how many occurrences were replaced. Review mode is turned off after apply. The text in the input is updated; there is no undo. This gives you a single action to replace all selected matches.
• Copy copies the current text (before or after apply) to the clipboard. Clear resets the text, the pairs (to one empty pair), the matches, and the review mode. This lets you reuse the result or start over.
• Optional AI suggestions: when the first pair has a find string of at least two characters, a button appears to get suggestions. Clicking it sends the find term to a backend service. The service may return a list of related phrases. You can click a phrase to add it as a new find and replace pair (with the same replace value as the first pair). This is optional and can fail; the main find and replace works without it.

Common Use Cases

You need to change a name or term everywhere in a document. You paste the document into the input, add one pair (find the old name, replace with the new name), and click Apply. All matches are replaced. If you want to skip one occurrence, switch to review mode, uncheck that match, then apply.

You have several words or phrases to replace with the same new text. You add multiple pairs with the same replace value and different find strings. The tool finds all matches for all pairs. You preview or review, then apply once to replace them all.

You need to match only whole words. You turn on whole word so that a find string like "cat" does not match inside "category". You run the search, check the preview or review list, and apply. When working with related formats, removing duplicate lines can be a useful part of the process.

You need a pattern (for example any number or any word). You turn on regex and enter a regular expression in the find field. The tool finds every match of that pattern. You set the replace string (which can include parts of the match if your regex has groups). You preview or review and apply. Invalid regex shows an error; fix the pattern and try again.

You want ideas for related search terms. You type a word in the first find field and click the suggestions button. If the service returns suggestions, you can add them as extra pairs and run find and replace on all of them. This step can fail; the main search and replace still works.

How to Use This Tool

1. Open the find and replace tool in your browser.
2. Paste or type the text you want to search in the input area. The text must be under 100000 characters. Watch the character counter if you paste a long document.
3. Add at least one find and replace pair. In the find field type the text or pattern to search for. In the replace field type what to put in its place. You can add more pairs with the Add Another Pair button (up to 20 pairs). Each pair is searched and all matches are collected together.
4. Set options if you need them. Open the Options section. Turn on Match case to match uppercase and lowercase exactly. Turn on Whole word to match only whole words (when regex is off). Turn on Regex to use the find string as a regular expression. The list of matches updates automatically.
5. Check the preview. The right pane shows your text with every match highlighted. Selected matches are shown in one color, deselected in another. Below it you see how many matches there are and how many are selected.
6. Optionally switch to review mode. Click Review Changes. The right pane shows each match with its position, context, matched text, and replacement text. Use the checkboxes to include or exclude matches. Uncheck any match you do not want to replace. Click Exit Review to go back to the highlighted preview.
7. Click Apply to replace all selected matches. The text in the input is updated. A message shows how many occurrences were replaced. Review mode is turned off. There is no undo; copy the text before applying if you might need to revert.
8. Copy the result to the clipboard if you need it elsewhere. Use Clear to reset the text and pairs and start over with new content.
9. Optionally use AI suggestions. Type at least two characters in the first find field. Click the suggestions button next to it. If suggestions appear, click one to add it as a new pair. This step can fail; the main find and replace does not depend on it.

Calculations & Logic

The tool builds a regular expression for each find string. If regex is off, special regex characters in the find string are escaped so the search is literal. If whole word is on and regex is off, the pattern is wrapped with word boundary markers. If regex is on, the find string is used as the pattern. The flags are global (find all) and, when match case is off, case-insensitive. The tool runs exec on the source text in a loop. Each match is recorded with its index, length, matched text, and the replacement string from its pair. Context before and after is taken as a short substring around the match. To avoid infinite loops, zero-length matches advance the search position, and the total number of matches per run is capped. Matches from all pairs are merged and sorted by index. Invalid regex throws; the tool catches it and shows an error message. In some workflows, encoding data in Base64 is a relevant follow-up operation.

When you apply, only selected matches are used. They are sorted by index in descending order. For each match, the text is updated by taking the substring before the match, the replacement string, and the substring after the match, and joining them. Replacing from the end first keeps earlier indices valid. The source text state is then set to the new text and review mode is turned off. The match list is recalculated from the new text and pairs on the next run.

Reference Tables or Scales

Options:

Limits: For related processing needs, generating regex patterns handles a complementary task.

Tips, Limitations & Best Practices

Use review mode when you want to replace only some matches. Uncheck the ones you want to keep, then apply. The preview shows all matches; review mode lets you change the selection before applying.

When using regex, test with a short sample first. Invalid patterns show an error message. Whole word is ignored when regex is on; add word boundaries in your pattern if you need them.

Replacement is applied in one step. There is no undo. Copy the text before applying if you might want to revert, or run the tool in a copy of the document.

AI suggestions are optional and can fail. You may see an error about credits or connection. The main find and replace does not depend on it. You can add and remove pairs manually.

Replacing from the end first avoids position shifts. Do not change the source text while in review mode if you want the selection to stay correct; apply or exit review first.