We are seeking an experienced Software Architect for a consultation engagement to design the technical blueprint of a scalable WhatsApp messaging system using low-cost APIs such as Z-API (or equivalent). This is not a full-service development role, but a strategic architecture assignment: defining the system structure, API integrations, automation flows, rate control logic, monitoring, and scalability best practices so our internal team can implement it. The ideal candidate must have proven experience with WhatsApp messaging infrastructure and API integrations, and specifically with designing systems that reduce the risk of WhatsApp blocking and account bans. This includes expertise in rate limiting, number warm-up strategies, opt-in/consent management, compliant messaging flows, and account health monitoring to maintain high deliverability and sender reputation.