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Big Design Up Front (BDUF): A Software Development Antipattern

Big Design Up Front (BDUF): A Software Development Antipattern


Big Design Up Front (BDUF) is a software development antipattern that involves creating a comprehensive and detailed design for a software system before starting the actual implementation. While it's essential to have some level of design and planning, the BDUF approach tends to be overly rigid and inflexible, making it difficult to adapt to changing requirements or unforeseen issues. It's important to note that "big" is vague, and the opposite of BDUF is not "zero design up front" or "no design up front." In this article, we will discuss the causes, consequences, and potential solutions for the BDUF antipattern.


The BDUF antipattern can arise from several factors, including:

  1. Overemphasis on planning: A belief that thorough planning and design can eliminate or minimize risks and uncertainties, leading to a misguided focus on creating a complete and detailed design before implementation.
  2. Misunderstanding of agile methodologies: A misconception that agile methodologies advocate for no planning or design, leading to a polarized view that favors BDUF.
  3. Resistance to change: An organizational culture that is resistant to change and values stability, leading to a preference for a fixed and comprehensive design upfront.
  4. Lack of trust: A lack of trust in the development team's ability to make sound design decisions during the development process, resulting in a preference for BDUF.


The BDUF antipattern can have several negative consequences:

  1. Reduced flexibility: A rigid and comprehensive design can make it difficult to adapt to changing requirements or unforeseen issues during the development process.
  2. Increased development time: BDUF can extend the development timeline due to the time-consuming nature of creating a detailed design upfront.
  3. Wasted resources: The time and effort spent on creating a comprehensive design can be wasted if the design becomes obsolete or requires significant changes during the development process. Time spent designing modules or approaches that are ultimately never used is often a complete waste.
  4. Reduced innovation: The BDUF approach may stifle innovation by discouraging experimentation and iterative improvements during the development process.


To address the BDUF antipattern, consider implementing the following strategies:

  1. Embrace iterative and incremental design: Adopt an iterative and incremental approach to design, allowing for regular review and refinement of the design throughout the development process.
  2. Focus on high-level design: Prioritize high-level design and architecture, while deferring detailed design decisions to the implementation phase.
  3. Encourage collaboration: Foster collaboration between stakeholders, designers, and developers to ensure that design decisions are informed by diverse perspectives and real-world constraints.
  4. Invest in continuous learning: Encourage the development team to continually learn and adapt their design skills and knowledge, building trust in their ability to make sound design decisions during the development process.


  • "As developers, we fail in two ways: we build the thing wrong or we build the wrong thing." - Steve "ardalis" Smith. BDUF increases both risks while trying to achieve the opposite.

Further Reading

  1. Agile Estimating and Planning
  2. Lean Software Development: An Agile Toolkit
  3. Article: Big Design Up Front vs. Evolutionary Design
  4. Article: Big Design Up Front (BDUF) or Evolutionary Design – Which Is Better?
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