Need experienced .NET developer/architect for ABDM (ABHA) M2/M3 integration with FHIR for healthcare platform

Project Overview:
We need a clean, well-documented, production-ready .NET-based ABDM integration component for our healthcare project. The solution must support ABDM/ABHA official workflows for M2 and M3 modules.

Expected Functional Scope:
• Integrate with official ABDM APIs for M2 (HIP) and M3 (HIU) workflows
• Consume ABDM requests and callbacks correctly
• On receiving ABDM data requests, query our internal healthcare database and generate the required FHIR-compliant resources/bundles
• Return/share health records back to ABDM in the required format, including encryption/security requirements
• Support consent-based health information exchange flows
• Support ABDM gateway communication, token/auth flows, callbacks, and auditability
• Design solution in .NET (preferably .NET 8 or latest stable enterprise version)

Mandatory Experience:
• Prior hands-on integration with ABDM / ABHA APIs
• Proven delivery in M2 and preferably M3 milestone implementations
• Strong understanding of HIP / HIU workflows
• Strong practical knowledge of HL7 FHIR resource and bundle generation
• Experience mapping healthcare databases to FHIR documents/resources
• Experience with callback/webhook handling, secure API design, logging, retries, and production support

Preferred Experience:
• Prior work on HMIS / EMR / LIS / hospital systems in India
• Experience with ABDM sandbox to production movement
• Experience supporting ABDM compliance/certification/testing process
• Experience with HFR/HPR/facility onboarding and ABDM ecosystem registration

Expected Deliverables:
1. Reusable .NET ABDM integration service/module
2. Internal APIs for our application to trigger ABDM workflows
3. FHIR mapping layer from our DB to required ABDM payloads
4. Callback/webhook handlers for ABDM flows
5. Security/encryption implementation as per ABDM requirements
6. Full source code with documentation
7. API documentation and deployment guide
8. Sandbox testing and bug fixing support
9. Production deployment support
10. Certification-readiness support and assistance during ABDM assessment/testing

Important:
This is not a basic API integration task. We need someone who has already worked on ABDM integrations and understands practical production issues, not just the documentation.

Please apply only if you can provide:
• Details of past ABDM/ABHA integration work
• Milestones handled (M2 / M3)
• Tech stack used
• Whether you built HIP, HIU, or both
• Whether you supported certification/compliance/testing
• Whether you can deliver a reusable .NET component with documentation