What The Diff

What The Diff is an AI-powered code review assistant that helps software development teams understand, document, and communicate changes made through pull requests. Rather than acting as a general-purpose coding assistant, it focuses on the development workflow around pull requests, automatically analyzing Git diffs and turning technical code changes into clear, human-readable explanations.

The platform connects to GitHub and GitLab and uses their APIs to retrieve pull-request or merge-request diffs. What The Diff then processes the changes with an AI model and generates descriptions explaining what changed and why. The company states that it does not store users’ code or pull-request diffs, and that the code is not used to train its AI model.

AI-Powered Pull Request Descriptions

One of What The Diff’s primary capabilities is automatically generating pull-request descriptions. Developers can use AI-generated summaries instead of manually documenting every change, helping teams make pull requests easier to understand before they are reviewed or merged.

The platform supports a shortcode-based workflow in which developers can place commands such as a summary request inside a pull-request description. What The Diff replaces the shortcode with AI-generated content based on the code diff.

It can also automatically add AI-generated summaries as comments on pull requests. Teams can configure triggers for new pull requests, pull-request updates, or manually applying a specific label.

AI Code Review and Refactoring

What The Diff extends beyond summarization with inline AI refactoring. Developers can request changes to specific code directly from the pull-request workflow rather than simply leaving a review comment asking another developer to make the modification.

This is intended for relatively minor improvements where an automated code change can reduce back-and-forth between reviewers and developers. The generated change can then be reviewed by the development team before being accepted.

Changelogs

What The Diff can transform development activity into automatically generated changelogs. Teams can share a public changelog containing project changes or consume changelog information through the platform’s JSON API for internal applications and workflows.

This makes the tool useful beyond the immediate code-review process because development teams can turn pull-request activity into a more accessible record of product changes.

Notifications and Team Communication

What The Diff is designed to make technical development progress understandable to people who do not work directly with source code.

Its summary notifications can send simplified descriptions of pull-request changes to Slack channels, Webhook endpoints, or selected recipients by email. The platform can also translate summaries into another supported language, allowing product managers, designers, clients, and other stakeholders to receive updates without needing to inspect the underlying code.

Weekly reports combine summaries of a project’s pull requests into a single progress report. These reports can also be delivered through Slack, Webhooks, or email.

Token-Based Processing

What The Diff uses a token-based pricing model. The number of tokens consumed depends largely on the size of the Git diff being processed. The company states that an average pull request uses approximately 2,300 tokens, while its getting-started documentation notes that typical daily pull requests can consume around 2,000–8,000 tokens.

Teams can configure token-related settings, including maximum tokens per pull request and repository-level controls. This allows organizations to reduce unnecessary consumption when dealing with large pull requests or automatically generated changes.

Repository-Level Controls

What The Diff allows teams to enable the service selectively for repositories. Administrators can configure individual repositories and decide how the AI assistant should operate.

Available controls include maximum tokens per pull request, excluded file patterns, exclusively included file patterns, ignored branches, and ignored pull-request titles. These controls can be useful for preventing unnecessary processing of generated files, documentation, CI-created pull requests, or other changes that do not require AI summaries.

The service does not impose a limit on the number of repositories that can be connected to an account; usage is instead governed by the available token allocation.

Privacy

Privacy is an important part of What The Diff’s positioning. According to its official FAQ, the service does not store users’ code or pull-request diffs. It uses the GitHub or GitLab API to retrieve the information required to analyze changes.

The company also states that its third-party services do not store the code and that user code is not used to train its AI model.

However, What The Diff requires broad repository access because GitHub and GitLab do not provide a permission specifically limited to reading pull-request diffs. Organizations should therefore review the permissions requested by the integration before connecting production repositories.

Supported Programming Languages

What The Diff states that it works with nearly all programming languages because it analyzes Git diffs rather than depending on a narrow list of language-specific integrations.

The AI can explain code changes in plain English and can generate summaries in other supported languages. The platform therefore works across a broad range of software projects rather than being limited to a specific programming ecosystem.

Pricing

What The Diff uses a usage-based token pricing model.

Free — $0/month

The Free plan provides:

• 25,000 tokens per month
• Approximately 10 pull requests
• Unlimited repositories
• Inline code refactoring
• Rate-limited usage
• No credit card required

Pro — $19/month

The Pro plan provides:

• 200,000 tokens per month
• Approximately 40 pull requests
• Unlimited repositories
• Instant code refactoring
• Slack notifications
• Webhook notifications
• Email notifications
• Priority email support

Unused tokens do not roll over into the next billing cycle. If users exhaust their allocation, they can upgrade to a larger plan or wait for the next billing cycle. What The Diff states that it does not automatically upgrade a customer’s plan.

The official pricing page currently lists the Free and Pro plans; no separate enterprise tier is publicly displayed.

Review

What The Diff is a focused AI development tool that solves a specific problem: making pull-request changes easier to understand and communicate. Its strongest feature is the automatic generation of clear PR descriptions from actual code differences, which can reduce repetitive documentation work for developers.

Its integration with both GitHub and GitLab makes it practical for teams using either of the two major Git hosting platforms. The addition of Slack, Webhook, and email notifications also extends its usefulness beyond developers, allowing product managers and other stakeholders to follow development progress without reading source code.

The changelog and weekly-report functionality gives the product additional value. Instead of limiting AI assistance to individual pull requests, teams can use summarized development activity for project communication and progress reporting.

The token-based pricing model is another advantage for smaller teams because there is a free tier and users can begin without a credit card. However, teams with large or frequent pull requests need to monitor token consumption carefully because large diffs consume more tokens and unused monthly tokens do not carry over.

A further consideration is repository access. What The Diff explains that it requires broad GitHub or GitLab repository access because those platforms do not offer a permission specifically for reading only pull-request diffs. Organizations with strict source-code access policies should evaluate this carefully before deployment.

What The Diff is best suited to development teams that want to automate PR documentation, improve communication around software changes, create changelogs, and reduce repetitive work during code review. It is less suitable for users looking for a complete autonomous coding environment or a general-purpose AI programming assistant.