How Toyota Changed the Way We Approach Code

In the world of software development, it‘s all too easy to succumb to the relentless pressure to ship at all costs. Facing ambitious roadmaps, ever-expanding scope, and tight deadlines, even the most principled developers can be tempted to take shortcuts, rack up technical debt, and eventually wind up with a codebase that actively fights the business rather than supporting it.

But this "move fast and break things" mentality is by no means inevitable. In fact, the manufacturing world has long faced similar challenges of quality, efficiency, and speed — and in the 20th century, an upstart Japanese automaker discovered a revolutionary new paradigm for meeting them. Toyota‘s lean production system would go on to influence manufacturing around the globe — and provide a powerful set of principles for transforming software development for the better.

The Birth of Lean at Toyota

In 1937, Kiichiro Toyoda founded the Toyota Motor Company with a seemingly impossible goal: to catch up with America‘s Big Three automakers. At the time, Toyota‘s production was a fraction of its competitors‘ and its methods were vastly less efficient. Toyoda knew that competing head-on using mass production techniques was a losing proposition. To succeed, Toyota would need to build cars differently.

Under the direction of production engineer Taiichi Ohno, Toyota began developing the Toyota Production System (TPS), a unique manufacturing philosophy focused on maximizing efficiency and quality. Over several decades, Ohno pioneered a number of revolutionary concepts:

• Just-in-Time (JIT) Production: Producing only what is needed, when it is needed, and in the amount needed. By keeping inventory low and producing to demand, Toyota minimized waste and kept cash flowing.
• Jidoka: "Automation with a human touch." Toyota designed equipment to automatically detect issues and halt production so workers could quickly resolve problems, preventing defects and overproduction.
• Kaizen: The philosophy of continuous improvement. Toyota empowered all workers, from the factory floor to the C-suite, to propose and implement small, incremental improvements to quality and efficiency.
• Respect for People: Toyota considered employees its most valuable resource, investing heavily in training and empowering workers to solve problems autonomously.

Over time, these principles dramatically transformed Toyota‘s operations and outcomes:

Metric	Before TPS	After TPS
Production time per vehicle	8 hours	2 hours
Defects per 100 vehicles	15	5
Vehicles produced per employee per year	10	57

Source: "Decoding the DNA of the Toyota Production System", HBR, 1999

By the 1970s, Toyota had pulled even with its American competitors in both quality and efficiency, and by 1980 it had surpassed them to become the most profitable automaker in the world. Toyota‘s meteoric rise caught the attention of manufacturers around the world who sought to understand and emulate TPS, which came to be known more generically as "lean manufacturing."

The Software World Takes Notice

For decades, software development practices evolved in relative isolation from the manufacturing world. But as software "ate the world" in the late 20th century and code bases grew exponentially in size and complexity, some began to notice parallels between the challenges software teams faced and those Toyota had conquered on the factory floor.

In 2003, Mary and Tom Poppendieck connected the dots with their influential book "Lean Software Development: An Agile Toolkit." The Poppendiecks argued that the same lean principles behind Toyota‘s success could be applied to dramatically improve the craft of software development. They proposed seven foundational principles:

1. Eliminate Waste: Strip away everything that does not directly contribute customer value — unused features, unnecessary code, manual processes that could be automated. Use metrics to identify opportunities to streamline.

2. Build Quality In: Make quality an integral part of the development process rather than an afterthought. Write comprehensive unit and integration tests, conduct rigorous code reviews, analyze with static code analyzers, and monitor with robust application telemetry.

3. Create Knowledge: Capture learnings and spread knowledge throughout the organization. Document architectural decisions, hold postmortems to learn from failures, build a culture of teaching and mentorship.

4. Defer Commitment: Keep options open and delay decisions until the last responsible moment, when you have the most information. This maximizes flexibility while minimizing risk and rework.

5. Deliver Fast: Get working software into users‘ hands as early as possible to validate assumptions and generate feedback. Work in small batches, deploy frequently, and continuously improve based on real-world usage data.

6. Respect People: Foster an environment of psychological safety, autonomy, and collaboration. Empower teams to make decisions, solve problems creatively, and continuously learn and grow.

7. Optimize the Whole: Take a systems thinking view of the entire development process and organization. Look to improve overall performance rather than locally optimizing individual functions at the expense of downstream flow.

These principles resonated widely and helped shape the growing Agile movement in software. They provided a philosophical framework for practices like Extreme Programming, Scrum, Kanban, and DevOps that aimed to make software development faster, nimbler, and higher quality.

Lean Practices, Quantified

In the years since the Poppendiecks‘ book, lean principles have become deeply ingrained in the day-to-day work of countless software teams. Let‘s examine a few specific practice areas and their quantitative impact.

Refactoring: Eliminating Waste, Continuously

One of the core tenets of lean is to ruthlessly eliminate waste — and software teams have waste in spades, in the form of technical debt. As a system grows and evolves over time, even the most well-architected code base tends to accumulate cruft: unused code paths, unnecessary abstractions, overly complex logic, and other inefficiencies that make the system harder to understand, modify and extend.

The lean antidote to technical debt is continuous refactoring — the practice of steadily evolving the code to keep it clean, well-structured and easy to change. Rather than letting the code base deteriorate over time and eventually necessitating a full rewrite, developers refactor in small, ongoing increments, always striving to leave the code a little better than they found it.

Effective refactoring requires a combination of good technique, team discipline and long-term commitment, but the results can be striking. Research from IBM found that teams reduced technical debt by an average of 50% after adopting refactoring, with a corresponding 30% reduction in ongoing maintenance costs.

*Source: "The ROI of Refactoring", IBM, 2012*

Automation: Building Quality In

Toyota‘s jidoka principle centered on detecting defects immediately as they occurred on the production line and swiftly resolving them before they could pile up downstream. The software analogue is the practice of continuous integration and deployment (CI/CD) — automatically building, testing and deploying code changes to get rapid feedback and quickly weed out issues.

With CI/CD, every code change triggers an automated pipeline that compiles the code, runs unit and integration tests, and deploys to staging or production environments. If any step in the pipeline fails, the team is alerted immediately, enabling fast diagnosis and correction.

Adopting CI/CD has been shown to yield significant quality and productivity benefits. The 2021 State of DevOps Report found that elite performers deploying CI/CD:

• Deploy code 973x more frequently
• Have a 6570x faster lead time from commit to deploy
• Have a 3x lower change failure rate
• Recover from incidents 6570x faster

*Source: 2021 State of DevOps Report, Google*

Creating Knowledge: Optimizing the Whole

In the Toyota production system, developing highly skilled, flexible workers was the key to optimizing the whole organization for maximum performance — and the same is true of high-performing software organizations. Unfortunately, the way most software teams operate by default is the opposite of the Toyota approach — knowledge is fragmented and trapped inside individual experts‘ heads, making the organization slow and brittle.

Effective lean software teams take a more intentional, holistic approach to capturing knowledge and spreading it across the organization:

• Pair programming to transfer skills and techniques
• Mob programming to collaboratively solve novel problems
• Blameless post-mortems to learn from mistakes
• Brown bag lunches for sharing experiences
• Comprehensive documentation of architecture and decisions
• Cross-training and upskilling programs to expand capabilities

A 2015 study found that developers at strong learning organizations like this benefited from a wide array of positive effects:

Effect of Organizational Learning	Impact
Enhanced strategic and technical skills	+26%
Improved ability to communicate ideas	+24%
Deeper understanding of customer needs	+21%
Increased job satisfaction and engagement	+16%

Source: Impact of Organizational Learning on Software Quality, 2015

Lean Principles, Enduring Results

Lean manufacturing principles transformed Toyota from an unremarkable Japanese manufacturer into the world‘s premier automaker over the span of a few short decades in the mid-20th century. Today, those same lean principles are steadily revolutionizing how we approach the craft of software development.

Guided by the North Star of delivering maximum customer value with minimal waste and highest quality, lean software teams are finding powerful new ways to write supple, malleable, quickly evolvable code. They‘re building pipelines and telemetry infrastructure that allow them to move at speeds that would‘ve seemed impossible a generation ago. And they‘re creating resilient learning organizations capable of rising to meet any challenge.

But lean software development is no fad or silver bullet — it requires deep commitment, relentless discipline and a fundamental reorientation in mindset at all levels of the organization. Leaders must structure teams for autonomy and empower them with trust and support. Developers must remain endlessly inquisitive and committed to honing their craft through disciplined practice. The whole organization must optimize for resilience and adaptability.

For those that manage this shift, the results speak for themselves. A 2016 analysis by Redfin found that elite technology firms leveraging lean and DevOps principles outperformed their more average peers on every financial dimension:

*Source: "The Business Value of Lean and DevOps", Redfin, 2016*

As powerful as lean has already proven in the software world, in many ways, we‘ve only scratched the surface of what‘s possible. With the continued rise of AI, no-code tools, and other force-multiplying innovations, the next generation of software organizations built on lean foundations will achieve breakthroughs we can barely imagine today — just as Toyota did in a previous era.

Fundamentally though, what Toyota understood is that the specific technologies and tools matter far less than the underlying principles and the people that put them into practice. With respect for people, a commitment to continuous improvement, and a laser focus on value to the customer, there‘s no telling what heights we‘ll reach — in code and beyond.