Code Comparison: Original vs Obfuscated
Compare original and obfuscated code side by side with our powerful diff engine. Features character-level change highlighting, syntax highlighting for multiple languages, synchronized scrolling between panes, and detailed diff statistics. Paste code or load a sample to see how obfuscation transforms your code. All processing is local and private.
Enter code in both panels to see differences
Paste your original and obfuscated code in the panels above, or load a sample to see how the diff engine works. The comparison updates in real-time as you type.
Why Use Our Code Comparison Tool?
Side-by-Side Code Comparison
View original and obfuscated code in a dual-pane layout with synchronized scrolling. Every change between the two versions is clearly visible with character-level diff highlighting, making it easy to see exactly how the obfuscation transformed each line of code.
Character-Level Diff Engine
Our intelligent diff algorithm performs line-level matching first, then drills down to character-level changes within each line. Added characters appear in green, removed characters in red, and modified sections are highlighted inline for precise change analysis.
Syntax Highlighting & Line Numbers
Both code panels feature full syntax highlighting with support for JavaScript, TypeScript, Python, HTML, CSS, SQL, and more. Line numbers with gutter markers show added and removed lines at a glance, making diffs easy to navigate.
Diff Statistics Dashboard
Get instant statistics about the comparison: total line count for each version, number of added, removed, and modified lines, character-level change count, and overall similarity percentage. Perfect for quantifying the impact of obfuscation.
Common Use Cases for Code Comparison
Verifying Obfuscation Correctness
After applying obfuscation techniques to your source code, use the comparison tool to verify that the output is functionally equivalent. Check that no code was accidentally dropped, no syntax errors were introduced, and the structure of the program remains intact. The character-level diff reveals even the smallest unintended changes.
Reviewing Code Transformations
When refactoring or transforming code with automated tools (minifiers, transpilers, obfuscators), review every transformation before deployment. The side-by-side comparison makes it easy to audit changes and confirm that the transformation preserved the intended behavior.
Educational: Understanding Obfuscation Effects
Learn how different obfuscation techniques transform code by comparing before and after versions. See how variable renaming changes identifiers, how string encoding hides literals, and how control flow flattening restructures loops and conditionals.
Debugging Obfuscated Code
When debugging obfuscated JavaScript or other code, map the minified or obfuscated output back to the original source. The comparison helps trace which parts of the original code correspond to which obfuscated sections, making debugging much more manageable.
Code Review & Security Auditing
Security auditors and code reviewers can use the comparison tool to analyze the impact of obfuscation on code behavior. Verify that obfuscation hasn't introduced vulnerabilities, and ensure that security-critical sections remain correctly implemented.
Comparing Deobfuscation Results
After running deobfuscation tools on minified or obfuscated code, compare the deobfuscated output against the original source (if available) to assess the quality of the deobfuscation. Identify which parts were successfully restored and which areas need manual attention.
Understanding Code Comparison & Diff Analysis
What is Code Comparison?
Code comparison (also known as diffing) is the process of analyzing two versions of source code to identify the differences between them. In the context of obfuscation, code comparison allows you to see exactly how the original source code was transformed, which parts were renamed, which strings were encoded, and whether any structural changes were made. Our tool provides both line-level and character-level diffing, giving you a complete picture of every change.
How the Diff Engine Works
- Line-Level Matching: The engine first compares lines between the two versions using a longest common subsequence (LCS) algorithm. This identifies which lines were added, removed, or remain unchanged. Matched lines are aligned side by side in the comparison view.
- Character-Level Diff: For lines that are partially modified (not simply added or removed), the engine performs a second pass at the character level. Each pair of matched lines is diffed character by character to identify insertions, deletions, and substitutions within the line.
- Visual Highlighting: Results are color-coded: green for additions, red for removals, and yellow for modifications. Gutter markers on the left edge provide a quick summary of which lines changed. Synchronized scrolling keeps both panes aligned as you navigate through the comparison.
Why Compare Original vs Obfuscated Code?
- Verification: Confirm that the obfuscation process preserved the functionality and structure of your code. No missing pieces, no syntax errors.
- Auditing: Review what information the obfuscation is hiding and what it might be exposing. Check that sensitive strings, API keys, and business logic are properly protected.
- Learning: Understand how different obfuscation techniques work by seeing their exact effect on your code. This is invaluable for security researchers, students, and developers evaluating obfuscation tools.
- Quality Assurance: Before deploying obfuscated code to production, use the comparison to verify that the output size, structure, and behavior meet your requirements.
Privacy, Security & Availability
Your code is processed entirely within your browser. No code is ever uploaded to any server, stored, logged, or shared with third parties. The tool requires no account creation, no signup, and imposes no file size limits. It is completely free with no premium tiers, usage caps, or hidden charges. You can use it as often as needed for verifying obfuscation, code reviews, security auditing, or educational purposes.
Related Tools
Multi-Tool Obfuscation Pipeline
Chain multiple obfuscation techniques in sequence: Base64, ROT13, URL encoding, reverse, and more. Build custom obfuscation pipelines with configurable order.
Batch File Obfuscation Tool
Upload multiple files and obfuscate them all at once. Download the obfuscated files individually or as a ZIP archive. Supports JavaScript, HTML, CSS, and more.
Obfuscation Strength Calculator
Calculate and score the strength of your obfuscation across four dimensions: reversibility, resistance, readability, and size overhead. Overall score from 1-10.
Obfuscation Cheat Sheet
Interactive reference guide covering all obfuscation techniques by category, with reversibility ratings, detection methods, and code examples for each.
Frequently Asked Questions About Code Comparison
A code comparison tool (also called a diff tool) analyzes two versions of source code and highlights the differences between them. It shows which lines were added, removed, or modified, and can display character-level changes within lines. This is essential for reviewing code transformations like obfuscation, minification, or refactoring.
Line-level diffing compares entire lines between two code versions, marking lines as added, removed, or unchanged. Character-level diffing goes a step further: for lines that are partially modified, it compares individual characters to show exactly what changed within the line. Our tool performs both passes for maximum accuracy.
Comparing original vs obfuscated code helps verify that the obfuscation preserved functionality, audit what information is being hidden (or exposed), understand how specific obfuscation techniques transform code, and ensure that no syntax errors or missing code was introduced during the obfuscation process.
Our tool supports syntax highlighting for a wide range of languages including JavaScript, TypeScript, Python, HTML, CSS, SQL, Java, C#, PHP, Ruby, Go, Rust, Swift, Kotlin, Bash, and many more. The diff engine works regardless of language - any text-based code can be compared with character-level precision.
The diff algorithm uses a longest common subsequence (LCS) approach for line matching, which provides highly accurate results for most code transformations. For modified lines, character-level diffing identifies changes at the finest granularity. The algorithm handles insertions, deletions, substitutions, and combinations of all three within the same block of code.
Absolutely. All code comparison and diff analysis happens entirely within your browser. Your code never leaves your device and is never sent to any server. No account is required, no data is stored, and no tracking occurs. This makes the tool completely safe for comparing sensitive proprietary code.
Since processing happens locally in your browser, the limit depends on your device's available memory. Most modern browsers can handle files with thousands of lines without issues. For extremely large files (10,000+ lines with dense changes), you may experience slower diff computation, but the tool will still produce accurate results.
Yes. Both code panes are synchronized so that scrolling in one pane automatically scrolls the other to the corresponding position. This keeps the aligned lines visible in both panes as you navigate through the comparison, making it easy to review changes across the entire file.
Yes, 100% free. There is no signup, no premium tier, no usage limits, and no file size caps. The tool runs entirely in your browser and will always be free to use on Aback Tools.