Job Description: We are seeking a senior SQL, backend developer to help implement the backend foundations for a complex reasoning platform. The core data architecture and schema design are already developed. We are now looking for an experienced engineer to help refine and implement the core backend structures correctly, cleanly, and securely. Project Scope & Long-Term Compensation: This project is structured in two distinct phases: 1.The Paid Trial Phase: We are hiring 2–3 qualified candidates simultaneously for a paid, fixed-price trial project (estimated 5–10 hours of work involving a high-level schema review and a small prototype subsystem design). 2. The Major Project: The candidate who performs best during the trial may be awarded the contract for the full major project.

• Rate Alignment Note: Please submit your proposal using the exact rate (hourly or milestone-equivalent) that you expect to maintain for the duration of the entire major project. We will not accept rate increases or contract renegotiations between the trial phase and the major project phase.
• Scope Note: This is strictly a backend and database project. Frontend, mobile, and AI development are outside the current scope.

Objective Evaluation Criteria Candidates in the trial phase will be measured on these metrics: 1. Schema Maintainability: The database structure must isolate configuration rules so that non-technical users can safely update weighting scores via a basic UI later (no hardcoded logic). 2. Audit Trail Integrity: The architecture must inherently track historical data changes (who, what, when, and why) without sacrificing database performance. 3. Deterministic Reliability: The system must produce identical, 100% reproducible results for identical datasets without exceptions. 4. Security & Compliance Readiness: The design must demonstrate clear foundational awareness of data privacy (e.g., structural isolation of sensitive data). 5. Extensibility: The schema must easily scale from an initial small prototype set of variables to tens of thousands without requiring structural redesigns. No anti-patterns, nested loops etc., we need the ability to scale significantly no performance degradation. 6. Communication & Documentation: Clear, concise documentation explaining your architectural choices.

Requirements

• Strong SQL expertise and experience implementing complex and efficient relational schemas.
• Backend/API development experience.
• Clear understanding of maintainable system design and data integrity.
• Professional communication skills and ability to work collaboratively.

Preferred

• Familiarity with FHIR/HL7 standards.
• Experience with auditability, versioning, and provenance systems.

To Apply, Please Include: 1. Examples of PostgreSQL systems you have personally implemented or designed. 2. Your experience with relational schema optimisation and data integrity. 3. Any healthcare systems experience you possess. 4. Your preferred backend stack for this type of project. 5. Confirmation of whether you personally perform the implementation work or delegate to a team.