SeeDiff local code diff viewer for Git and AI coding agents

SeeDiff Review 2026: A Local Code Diff Viewer for AI Coding Workflows

Modern software development is changing quickly. AI coding agents can now generate large amounts of code in a short period of time, but this creates another challenge: developers still need to understand, inspect and review those changes.

When a project contains hundreds or thousands of changed lines across many files, a traditional Git diff can become difficult to navigate.

SeeDiff is a developer tool created to address this problem.

It is a free and open-source local code diff viewer that allows developers to inspect large Git changes while keeping track of which parts have been seen and which parts have actually been reviewed. The project is specifically optimized for workflows involving AI coding agents.

SeeDiff at a Glance

Feature	Details
Tool Type	Local Git code diff viewer
Primary Purpose	Reviewing large code changes
AI Focus	Optimized for AI coding agents
Price	Free
License	Open Source / MIT
Technology	Python, HTML and CSS
Supported Systems	macOS, Linux and Windows
Python Requirement	Python 3.10+
Internet Required	No – local operation
Accounts	No account required
Telemetry	No telemetry

These details are based on SeeDiff's official website and project information.

The Problem SeeDiff Is Trying to Solve

Code review becomes increasingly difficult as software projects become larger.

A small Git diff might be easy to understand. However, an AI coding agent can potentially modify dozens of files and generate thousands of lines of changes.

At that point, developers can face questions such as:

Which files have I already checked?
Which changes have I only seen?
Which sections still need review?
Where did I stop reviewing yesterday?
Did I accidentally skip an important change?

SeeDiff focuses specifically on this review-progress problem.

What Is SeeDiff?

SeeDiff is a local code diff viewer designed for reviewing Git changes.

The official project describes it as a “Code diff viewer with progress tracking” and says it is optimized for AI coding agents.

Unlike a traditional diff viewer that mainly displays changes, SeeDiff adds a layer of review-state tracking.

It distinguishes between code that has been seen and code that has been explicitly reviewed.

Seen vs Reviewed

This is one of SeeDiff's most interesting ideas.

A code block can automatically become marked as Seen when it passes through the user's viewport.

However, seeing a change does not necessarily mean the developer has actually reviewed it.

SeeDiff therefore provides a separate Reviewed state that can be explicitly marked by the user.

This distinction can make large reviews easier to manage because developers can identify sections that were visible but still require deliberate inspection.

Why This Matters for AI-Generated Code

AI coding agents can significantly increase developer productivity, but they can also generate large changes very quickly.

The more code an AI system creates, the more important human review becomes.

SeeDiff's approach is based on the idea that AI and humans should work together rather than treating AI-generated code as automatically trustworthy.

The project's own philosophy emphasizes the importance of trained human eyes reviewing the changes produced by AI coding agents.

How SeeDiff Fits into an AI Coding Workflow

A typical workflow could look like this:

AI Coding Agent
       ↓
Generates Code
       ↓
Git Changes
       ↓
SeeDiff
       ↓
Developer Reviews Changes
       ↓
Approved / Modified Code
       ↓
Commit or Pull Request

This gives the developer a dedicated place to inspect what an AI coding agent has changed.

Large Diff Support

SeeDiff is designed with large changes in mind.

The official website states that its virtualization allows a 40,000-line file to scroll smoothly.

This is particularly relevant for large repositories and AI-assisted development, where a single coding session can potentially generate a substantial amount of code.

Progress Tracking

One of the biggest advantages of SeeDiff is review-progress tracking.

Instead of treating a diff as a static document, SeeDiff keeps track of the review process.

The project states that review progress can survive:

Rebases
Amends
Closing the browser window
Returning to the project later

This means developers can stop a large review and continue later without losing their place.

Minimap for Code Review

SeeDiff includes a minimap along the side of the file.

The minimap provides a quick visual representation of what has been seen, what has not been seen and what remains unreviewed.

For large files, this can provide a useful overview without requiring the developer to scroll through the entire file repeatedly.

Search Across Changed Files

Searching is another important part of large-scale code review.

SeeDiff's search functionality can search the current file as well as other changed files.

This allows developers to locate particular functions, variables, strings or patterns without manually opening every changed file.

Keyboard-Driven Code Review

SeeDiff is heavily designed around keyboard navigation.

Some of its shortcuts include:

Shortcut	Action
← / →	Previous or next change block
↑ / ↓	Previous or next file
R	Mark a block as reviewed
N / n	Next or previous unreviewed block
j / k	Scroll lines
V	Mark seen-but-unreviewed blocks as reviewed
f	Mark the entire file as reviewed
s	Switch diff view mode
Ctrl + F	Search changed files
g	Focus file filter
h	Hide fully reviewed files
t	Change theme
?	Open help

These keyboard controls are documented on the official SeeDiff website.

Unified and Side-by-Side Views

Developers have different preferences when reviewing code.

SeeDiff provides the ability to switch between unified and side-by-side diff views.

This gives users flexibility when comparing old and new versions of code.

Multiple Themes

SeeDiff is not limited to a single visual theme.

The project currently provides six themes, with matching syntax palettes designed to keep the interface visually consistent.

Available themes shown by the project include:

Solarized Dark
Hailmary
Light
Dark
Solarized Light
Space

Local-First Architecture

Privacy is another major characteristic of SeeDiff.

The project states that nothing leaves your machine and that it does not require accounts, telemetry or network calls outside localhost.

This is particularly useful for developers working with private repositories or proprietary source code.

Why Local Code Review Can Be Useful

Source code can contain sensitive information such as:

Business logic
Private APIs
Internal infrastructure details
Credentials or configuration references
Proprietary algorithms
Customer-related code

A local tool can reduce concerns about sending source-code content to an external service.

SeeDiff's official site specifically describes the application as local and says it makes no network calls outside localhost.

Installation Requirements

SeeDiff requires:

Python 3.10 or newer
Git

The official project provides installation approaches for macOS, Linux and Windows.

Installing SeeDiff with uv

One recommended installation approach uses uv.

The official instructions provide the following command:

uv tool install git+https://github.com/acme-dot-bot/seendiff

After installation, the tool can be run from inside a Git repository.

Running SeeDiff

Once installed, move into a Git repository and run:

cd ~/my-project
seendiff

The project states that SeeDiff automatically selects a free port, starts a local server and opens the browser.

Comparing Against Different Git References

SeeDiff can also be launched against different Git references.

Examples include:

seendiff main

seendiff HEAD~3

seendiff --port 8700

The official documentation explains that the tool can use branches, tags or SHAs as the comparison base.

Simple Installation Philosophy

SeeDiff aims to keep its setup lightweight.

The project describes itself as having minimal dependencies, requiring no build process and no configuration file.

This makes it appealing to developers who want a focused tool instead of a large development platform.

SeeDiff and Git

SeeDiff is built around Git repositories.

Instead of replacing Git, it provides a visual review layer on top of Git changes.

Developers can use their existing Git workflow while using SeeDiff to inspect and track the review process.

SeeDiff for AI Coding Agents

AI coding agents are one of the main reasons a tool like SeeDiff is becoming relevant.

An AI coding agent can modify multiple files while implementing a feature or fixing a problem.

That can create a large diff that needs human inspection.

SeeDiff provides a dedicated environment where developers can systematically work through those changes.

Code Walkthrough Mode

SeeDiff also includes a code walkthrough skill designed for AI coding agents.

The concept is simple: an AI coding agent can explain the changes it made step by step while the developer follows the explanation alongside the relevant code.

The official project describes this as a walkthrough mode where an AI coding agent explains a diff step by step.

AI + Human Code Review

The walkthrough concept highlights an important idea.

AI can be extremely effective at writing code, but developers still need to understand the design decisions behind that code.

A workflow that combines:

AI-generated implementation
AI-generated explanation
Human review
Developer judgment

can provide a more balanced development process.

Security and Privacy

Because SeeDiff runs locally, developers can inspect their code without uploading the diff to a hosted review service.

The project explicitly states that there are no accounts, no telemetry and no network calls outside localhost.

For teams handling sensitive source code, this local-first approach can be an important advantage.

Performance

Large code reviews can become difficult when the browser interface has to render huge files.

SeeDiff uses virtualization to improve performance when working with large diffs.

The official website specifically mentions smooth scrolling for a 40,000-line file.

Advantages of SeeDiff

Free to use
Open source
Local-first design
No account required
No telemetry
Designed for large diffs
Review-progress tracking
Keyboard-driven workflow
Search across changed files
Minimap for large files
Multiple themes
AI coding agent integration
Code walkthrough capability
Supports Windows, macOS and Linux

Possible Limitations

SeeDiff is intentionally focused on a specific problem, so it is not designed to replace every part of a modern software development platform.

It is primarily a local diff-review tool rather than a complete Git hosting service.

Developers looking for features such as pull-request management, team collaboration dashboards, issue tracking or cloud repository hosting will still need other tools.

SeeDiff also requires Git and Python 3.10 or newer, so it is primarily targeted at developers who are comfortable working with development environments.

SeeDiff vs Traditional Git Diff

Traditional Git Diff	SeeDiff
Shows code changes	Shows code changes with review tracking
Limited review-state awareness	Seen and reviewed states
Basic navigation	Keyboard-focused navigation
Large diffs can be difficult to manage	Designed for large diffs
No dedicated review progress	Review progress is preserved
Basic file navigation	Search and file filtering
Generic workflow	Optimized for AI-assisted coding

Who Should Use SeeDiff?

AI-Assisted Developers

Developers who frequently use AI coding agents may benefit the most from SeeDiff because large AI-generated changes are one of its primary use cases.

Software Engineers

Engineers working with large repositories can use SeeDiff to systematically inspect complex changes.

Open-Source Contributors

Open-source developers can use the tool to review changes locally before submitting a contribution.

Security-Conscious Developers

Developers who prefer to keep source code on their own machine may appreciate SeeDiff's local-only architecture.

Code Reviewers

Anyone who regularly reviews large Git diffs may find the progress-tracking functionality useful.

A Practical SeeDiff Workflow

A simple workflow could look like this:

Make changes using an editor or AI coding agent.
Save the changes in your Git repository.
Run SeeDiff.
Review each changed file.
Use the minimap to identify unreviewed areas.
Use keyboard shortcuts to move between changes.
Mark important blocks as reviewed.
Search across changed files when necessary.
Use the walkthrough feature to understand AI-generated changes.
Finish the review before committing or merging.

Why SeeDiff Is Interesting in 2026

The development process is increasingly moving toward AI-assisted programming.

As AI coding agents become capable of modifying larger parts of software projects, the bottleneck can shift from writing code to understanding and reviewing code.

SeeDiff addresses that specific problem.

Its core idea is simple:

AI can help write the code, while humans remain responsible for understanding and reviewing the changes.

This makes SeeDiff particularly relevant to modern AI-assisted software development.

Final Verdict

SeeDiff is a focused developer tool with a clear purpose.

It does not try to become another massive software development platform. Instead, it concentrates on making large Git diffs easier to inspect and review.

Its strongest features include review-progress tracking, seen-versus-reviewed states, large-diff performance, keyboard navigation, search, minimaps, local execution and AI coding-agent workflows.

The fact that it is free, open source and local-first makes it especially interesting for developers who want a lightweight tool without accounts, telemetry or cloud-based source-code processing.

For developers working with AI coding agents or large repositories, SeeDiff is definitely worth exploring in 2026.

Frequently Asked Questions

What is SeeDiff?

SeeDiff is a local code diff viewer with progress tracking, designed for reviewing large Git changes and optimized for AI coding agents.

Is SeeDiff free?

Yes. The official website describes SeeDiff as free and open source.

Is SeeDiff open source?

Yes. SeeDiff is open source and the project is published under the MIT license.

Does SeeDiff require an account?

No. The project states that it does not require accounts and does not use telemetry.

Does SeeDiff upload source code?

According to the official website, nothing leaves the user's machine and the application makes no network calls outside localhost.

What operating systems support SeeDiff?

The project provides installation instructions for macOS, Linux and Windows.

What Python version does SeeDiff require?

SeeDiff requires Python 3.10 or newer along with Git.

Can SeeDiff handle large files?

Yes. SeeDiff uses virtualization and the official website states that a 40,000-line file can scroll smoothly.

Is SeeDiff useful for AI-generated code?

Yes. The project is specifically optimized for AI coding agents and includes a walkthrough mode intended to help developers understand AI-generated changes.

Conclusion

AI-assisted programming is changing how software is created, but better code generation also creates a greater need for effective code review.

SeeDiff approaches this challenge with a simple but useful concept: help developers see large Git changes, track what they have reviewed and understand changes produced by AI coding agents.

With local execution, no accounts, no telemetry, large-diff support, keyboard navigation, search, minimaps and review tracking, SeeDiff provides a lightweight alternative for developers who want more control over their code-review workflow.

If you regularly work with Git repositories and AI coding tools, SeeDiff is a developer utility worth adding to your toolkit.

Official Website: SeeDiff

GitHub Repository: acme-dot-bot/seendiff

This article is based on information published on the official SeeDiff website. Features, installation methods and project capabilities may change as the open-source project evolves.