Why Investors Bet $81M on Code Review CompanyㅣGraphite, Merrill Lutsky

Key Concepts

• Code review platform for the age of AI
• Agentic AI code review companion (Diamond)
• Stacked pull requests
• Inner loop vs. outer loop of software development
• AI code generation and its impact on software engineering
• Trust and security in enterprise adoption of AI tools

Graphite: Code Review for the AI Era

Graphite is a code review platform designed for the age of AI, aiming to accelerate the code review process by combining best-in-class workflows and tooling from companies like Google and Meta with an agentic AI code review companion named Diamond, powered by Anthropic. The company recently announced a $52 million Series B and has experienced 20x growth in the past year.

Origin and Inspiration

Graphite was born out of the observation that engineers transitioning from companies like Google and Meta found existing code review tools outside those organizations to be significantly slower and less productive. The founding team recognized a gap between the internal tools used at large tech companies and what was available to other companies.

Importance of User Understanding

The CEO emphasizes the importance of deeply understanding and caring about the user. Sustained enthusiasm for building a product requires a genuine desire to improve the lives of users and solve their problems. The Graphite team uses their own product daily and receives constant feedback from friends at other companies, fostering a strong connection to their user base.

Stacked Pull Requests

Graphite initially focused on stacked pull requests, which involve breaking down large changes into a series of smaller, dependent changes. This approach offers several advantages:

• Improved Reviewability: Smaller pull requests are easier to review thoroughly.
• Increased Development Speed: Engineers spend less time waiting for reviews and can continue working on other tasks.
• Data-Driven Results: Case studies show significant improvements in development speed, such as saving 7 hours per developer per week at Asana and increasing development speed by 3x at Ramp.

The speaker quotes an advisor saying, "Once you stack, you don't go back," highlighting the user excitement and engagement associated with Graphite.

The Outer Loop and AI's Impact

While tools like Cursor, Windsurf, and Copilot have accelerated code generation (the "inner loop"), the "outer loop" of code review, testing, deployment, and impact measurement remains a critical part of the software development process. AI code generation has amplified the need for better tools in this outer loop.

Shifting Roles in Software Engineering

The rise of AI code generation is transforming the role of software engineers. The limiting factor is shifting from "how do I build this?" to "what should I build?" and "how do I differentiate it?". The best engineers are becoming more like product thinkers, business thinkers, and designers. Software engineering is evolving to resemble code review, design, and product management more than traditional coding.

Graphite's Position in the AI Landscape

Graphite is positioned to capitalize on the increased need for efficient code review in the age of AI. The company's existing tooling for accelerating the outer loop and its established trust with enterprise customers provide a strong foundation for deploying AI-powered code review solutions.

Building Trust and Security

Gaining the trust of enterprise customers to access their code repositories requires a long-term approach:

1. Progressive Value Delivery: Consistently shipping new features and demonstrating the ability to deliver on promises.
2. Security Best Practices: Investing in security measures, including regular penetration testing.
3. Climbing the Ladder: Starting with smaller companies and gradually building trust over time.

Conclusion

Graphite is a code review platform that addresses the challenges of modern software development, particularly in the context of AI code generation. By focusing on the outer loop, providing tools for stacked pull requests, and prioritizing trust and security, Graphite aims to accelerate the code review process and empower engineers to be more productive and strategic. The company's growth and adoption by major technology companies demonstrate the value of its approach.