Senior AWS / Full-Stack SaaS Engineer – Final Hardening & Production Readiness

SignBas3 is a multi-tenant SaaS platform for sign and print businesses that is entering its final engineering and production-readiness phase. Product overview: https://signbas3.com This is not a greenfield build. The application, automated checks, deployment controls and operational runbooks already exist. We need a senior, hands-on engineer who can independently review the current system, help close remaining development work, harden the infrastructure and provide a practical go-live readiness sign-off. Current stack includes React/Vite, Node.js/TypeScript, PostgreSQL, AWS CDK/CloudFormation, App Runner, ECS/Fargate workers, SQS, S3/CloudFront, Secrets Manager and GitHub Actions. Initial paid engagement (approximately 10–15 hours): - Review application architecture, AWS infrastructure and release/deployment paths - Assess tenant isolation, IAM, secrets handling, network exposure and security controls - Review PostgreSQL resilience, backups, recovery, migrations and data-integrity risks - Assess logging, monitoring, alerting, operational readiness and cost/reliability risks - Identify launch blockers and produce a prioritised remediation plan and go-live checklist - Confirm what evidence is required for a credible production-readiness sign-off Follow-on work may include implementing agreed remediations, improving CI/CD and infrastructure-as-code, supporting final testing and helping complete the production launch. We value direct evidence, least-privilege access, clear documentation and careful handling of production systems. Initial access will be controlled and read-only where practical. Please address these points in your response: 1. Your direct experience with AWS CDK/CloudFormation, App Runner or ECS/Fargate, SQS and PostgreSQL 2. Examples of multi-tenant SaaS hardening or production-readiness reviews you personally completed 3. Your proposed deliverables for the first 10–15 hours 4. Weekly availability, earliest start date and overlap with Australian business hours 5. Whether you personally perform the work or involve an agency/team Please also mention one observation from the SignBas3 marketing website so we know you reviewed the product context.