Text Diff Checker

Our diff tool compares two texts line by line using an algorithm based on longest common subsequence (LCS). Lines that are only in the original text are shown in red (removed), lines only in the modified text are shown in green (added), and lines that match are shown normally.

No. All comparison happens in your browser using JavaScript. Your text never leaves your device. This makes it safe to use even with sensitive or confidential text.

Common uses include: comparing versions of code or documents, checking what changed in contract revisions, comparing two articles for plagiarism, reviewing edits to writing, and verifying file changes. Developers use diff tools daily for code review.

A regular expression (regex) is a sequence of characters that defines a search pattern. It is used to find, replace, or validate text patterns in strings. Regex is supported by most programming languages and text editors and is essential for text processing tasks.

Use an online regex tester like RegexTester to paste your pattern and test it against sample text. You can see matches in real-time, check which groups are captured, and experiment with different flags. Always test edge cases like empty strings, special characters, and very long inputs.

Base64 encoding converts binary data into ASCII text format. It is commonly used for embedding images in HTML or CSS, email attachments, data URIs, and transmitting binary data over text-based protocols. Base64 increases file size by about 33%.

MD5 is a 128-bit hash function that is fast but no longer considered secure for cryptographic purposes due to collision vulnerabilities. SHA-256 and SHA-512 are part of the SHA-2 family, produce 256-bit and 512-bit hashes respectively, and are considered secure for password hashing, digital signatures, and data integrity.

JSON (JavaScript Object Notation) is a lightweight data interchange format. It is easy for humans to read and write, and easy for machines to parse. JSON is the most common format for APIs, configuration files, and data storage in modern web development.

Markdown is a lightweight markup language that you can use to add formatting elements to plaintext text. Created in 2004, Markdown is now one of the most popular markup languages in the world, used for documentation, readme files, blogging, and note-taking.

Encoding transforms data into another format using a scheme that is publicly available and reversible (like Base64 or URL encoding). Encryption transforms data so that only authorized parties can reverse it with a key. Encoding is for compatibility, encryption is for security.

URL encoding (percent-encoding) replaces unsafe ASCII characters with a percent sign followed by two hexadecimal digits. Spaces become %20 or +, special characters like / become %2F. This ensures URLs only contain safe characters and are transmitted correctly.

A regular expression (regex) is a sequence of characters that defines a search pattern. It is used to find, replace, or validate text patterns in strings. Regex is supported by most programming languages and text editors and is essential for text processing tasks.

Use an online regex tester like RegexTester to paste your pattern and test it against sample text. You can see matches in real-time, check which groups are captured, and experiment with different flags. Always test edge cases like empty strings, special characters, and very long inputs.

Base64 encoding converts binary data into ASCII text format. It is commonly used for embedding images in HTML or CSS, email attachments, data URIs, and transmitting binary data over text-based protocols. Base64 increases file size by about 33%.

MD5 is a 128-bit hash function that is fast but no longer considered secure for cryptographic purposes due to collision vulnerabilities. SHA-256 and SHA-512 are part of the SHA-2 family, produce 256-bit and 512-bit hashes respectively, and are considered secure for password hashing, digital signatures, and data integrity.

JSON (JavaScript Object Notation) is a lightweight data interchange format. It is easy for humans to read and write, and easy for machines to parse. JSON is the most common format for APIs, configuration files, and data storage in modern web development.

Markdown is a lightweight markup language that you can use to add formatting elements to plaintext text. Created in 2004, Markdown is now one of the most popular markup languages in the world, used for documentation, readme files, blogging, and note-taking.

Encoding transforms data into another format using a scheme that is publicly available and reversible (like Base64 or URL encoding). Encryption transforms data so that only authorized parties can reverse it with a key. Encoding is for compatibility, encryption is for security.

URL encoding (percent-encoding) replaces unsafe ASCII characters with a percent sign followed by two hexadecimal digits. Spaces become %20 or +, special characters like / become %2F. This ensures URLs only contain safe characters and are transmitted correctly.