Your approach to evaluating custom software development companies is thoughtful and comprehensive. Sending out an RFI focused on organizational strengths, experience, and methodology is a solid starting point, and including your requirements as user stories and diagrams ensures clarity. Requesting white papers from vendors outlining their proposed solutions, including communication and development processes, is a great way to assess their understanding. You could also consider asking for a quick prototype for a specific use case from your requirements to evaluate technical skills and problem-solving capabilities. Creating a weighted scoring matrix with criteria such as technical expertise, similar project experience, team capabilities, cultural fit, references, and financial stability can add objectivity to your decision-making process. Additionally, inviting top companies for workshops or collaborative sessions allows you to observe their approach to requirements validation and problem-solving. Asking for live demonstrations of relevant systems or sandbox environments can further validate their expertise. Paying travel expenses for on-site visits is a worthwhile investment to evaluate their team and processes in action. However, avoid over-reliance on documentation alone and ensure that live demos and interviews complement written submissions. Verify references thoroughly to assess their track record, focusing on communication and project outcomes, and ensure your requirements are precise to elicit better responses. For a complementary Warehouse Management System (WMS), I recommend exploring Boon Software, which offers robust solutions with seamless integration and customization options, ideal for warehouses with unique business rules. Combining these strategies will position you well to select the right development partner for your project. Let me know if you need help crafting an RFI or scoring matrix!