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Diff Viewer

Visually compare differences between two text blocks and instantly identify additions, removals, and changes.
Line breaks and whitespace differences are also highlighted, helping you catch even subtle modifications.

This tool is useful for reviewing documents, proofreading content, and checking revisions in source code or specifications.
All comparisons are performed directly in your browser, and no text is sent to any server.

Guide: How to use & features

  • Paste the original text on the left and the modified text on the right, then click “Show diff.”
  • Additions appear in green and removals in red, making changes easy to spot.
  • After viewing, use the copy buttons under each pane to share either version.
  • Very large inputs may take a few seconds to render—please keep the tab open until it finishes.

Samples: Sample input & output

Compare two short files

Input

Left
console.log("hello");
Right
console.log("hello world");

Output

- console.log("hello");
+ console.log("hello world");

FAQ: Frequently asked questions

  • How are whitespace differences handled?

    Diffs are shown per line and include spaces, tabs, and line breaks. Cleaning up stray whitespace before pasting makes the output easier to read.

  • Is it okay for large snippets?

    Processing happens in the browser; a few thousand lines is typically fine. For bigger files, split them into sections before comparing.

  • Can I save the diff?

    Use copy to grab the rendered diff text. You can also take a screenshot or rely on your browser’s save/share features if needed.

Use cases: Common use cases

  • Comparing config or environment changes

    Quickly diff updated .env or YAML/JSON files to review tweaks and catch unintended edits.

  • Checking generated output

    Paste build artifacts or codegen results to see exactly what changed between runs.

  • Sharing minimal edits

    Extract only the relevant lines as a diff to discuss changes in PR comments or chat.

Notes: Notes & limitations

  • Work stays in your browser

    Inputs and outputs remain local. Closing the tab or clearing cache will remove any temporary state.

  • Validate critical data

    Results are helper outputs—double-check them before sending to production systems or sharing externally.

  • Large payloads depend on your device

    Very large text or files can feel slow in some browsers. Use a desktop environment for heavy workloads.
Result

Text Diff and Comparison Tool

This text diff tool compares two pieces of text and highlights added, removed, and changed lines. It is useful for code snippets, configuration files, documentation drafts, logs, generated output, and any situation where small changes are easy to miss by eye.

When to use it

  • Review code before committing: Compare an old snippet with a new one and catch accidental edits.
  • Check configuration changes: Compare JSON, YAML, .env, server configs, or deployment settings.
  • Edit documentation: See exactly which sentences or lines changed between two drafts.

Review tip

Whitespace, indentation, and line endings can appear as differences. When reviewing a diff, separate meaningful content changes from formatting-only changes so you can focus on the behavior or wording that actually changed.

Articles for this tool

Introduction
2026-01-21

How to Read Text Diffs: Understanding Line-Level and Word-Level Comparison

Learn how to read diffs: the meaning of + and -, line vs. word-level comparison, handling whitespace and line endings, and practical uses in code review.

Recent Articles

Introduction
2026-08-03

How CREATE TABLE Generation From a Visual Table Design Works | DDL Builder

A look inside DDL Builder, which turns a visually designed table into CREATE TABLE statements and an ER diagram. Covers the MySQL/PostgreSQL/SQLite type-mapping rules and the column-inference algorithm used for JSON samples.

Use Case
2026-07-21

GitHub Actions needs Design Patterns: Speed Up CI, Avoid the Anti-Patterns

A pattern reference for GitHub Actions job dependencies (needs). Covers diamond-shaped fan-out, concurrency cancellation, fail-fast tradeoffs, matrix-plus-needs gotchas, and reusable workflows, with copy-paste YAML examples.

Use Case
2026-07-21

SQL JOIN Types: Complete Reference to INNER, LEFT, RIGHT & FULL

A reference for SQL JOIN types (INNER/LEFT/RIGHT/FULL/CROSS/SELF) with a cheat sheet and row-count walkthroughs. Covers why one-to-many joins duplicate rows, the WHERE-vs-ON NULL trap, and how to write multi-table joins.

Introduction
2026-07-16

Case Converter: camelCase, snake_case & kebab-case — 9 Styles at Once

Convert identifiers between camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case and more — all nine styles side by side. Handles acronym runs like HTTPServer, digits, and bulk multi-line conversion.

Introduction
2026-07-16

LLM API Cost Calculator: Compare Claude, GPT & Gemini Pricing Side by Side

Paste a prompt, set the expected output tokens, and compare per-request API costs across Claude, GPT and Gemini models. Covers input/output pricing structure, auto-updated price tables, and estimate limits.

Use Case
2026-07-14

AGENTS.md, CLAUDE.md, Cursor Rules: One Source of Truth for AI Coding Agents

Every AI coding agent wants its own rules file. Compare AGENTS.md, CLAUDE.md, .cursor/rules, copilot-instructions.md and more — what to write, a copy-paste template, and how to stop them drifting apart.

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