Role: Senior Solution Architect End Client: Lucidpoint Rate: $85/hr on C2C Key Skills: Twilio Platform Expertise, .NET (C# / ASP.NET Core), AWS, Healthcare Domain Client is seeking a Principal Voice Platform Engineer to serve as our primary subject matter expert (SME) for Twilio-based telephony architecture on enterprise healthcare communication programs. This is a senior individual-contributor and technical leadership role — you will not just build systems, you will define the architecture that all migration engineers follow. You will be the go-to expert for designing, validating, and governing Twilio Voice SDK, Twilio Studio, WebHooks and TwiML orchestration solutions at scale — including patterns and techniques that go well beyond what is documented in Twilio's public SDK guides. Your work directly enables healthcare organizations to migrate off end-of-life telephony infrastructure (Genesys PureConnect, Cisco, Avaya) onto modern cloud-native Twilio+.NET platforms without clinical disruption. Why This Role Exists: Our healthcare clients cannot afford to discover architectural mistakes in UAT or production. This role is the insurance policy — someone who has already hit the edge cases, knows the undocumented platform limits, and architects solutions that work at the first clinical go-live. What You'll Do Architecture & Design (Primary)
Own the end-to-end Twilio platform architecture for healthcare communication migration programs, including inbound call path design, Studio Flow topology, TwiML webhook orchestration, and carrier-layer configuration
Define and enforce the "Thin Studio, Smart API" architectural pattern — governing which logic lives in Twilio Studio vs. the .NET Voice API backend — across all delivery teams
Design the shared infrastructure services that all milestone teams consume: Redis-backed Call Session Store, CloudFront CDN audio serving, carrier redundancy configurations, and Twilio webhook reliability patterns
Architect Twilio solutions for complex multi-tenant IVR systems with 500+ simultaneous call flows, including multi-level DTMF menus, ASR (speech recognition) workflows, on-call routing chains, and call transfer sequences
Design and document DTMF fallback paths, ASR failure recovery strategies, and carrier redundancy patterns appropriate for 24/7 healthcare-grade production environments
Produce Architecture Decision Records (ADRs) for all significant platform decisions, with explicit documentation of trade-offs, alternatives considered, and healthcare-specific constraints
Technical Leadership
Lead the M0 AI Architectural Analysis sprint on migration programs — driving handler-to-architecture mapping, Studio/API boundary definition, and call flow dependency graph production
Conduct weekly architecture reviews with delivery teams, validating implementation against established patterns and catching deviations before they reach staging
Mentor .NET engineers on Twilio SDK patterns, webhook idempotency, stateless TwiML generation, and the operational differences between Twilio Studio and programmatic Voice API approaches
Review all Twilio-related pull requests as technical lead — checking for correctness against clinical load profiles, platform limits, and production reliability requirements
Define and own the NFR (non-functional requirement) story set for each engagement: webhook response SLA gates, load test acceptance criteria, CDN warm-up procedures, and carrier failover validation
Client Engagement
Present client's independent architectural recommendations to customer engineering and executive teams — clearly articulating trade-offs between platform approaches and the risks of common anti-patterns
Lead story elaboration workshops for Twilio-heavy initiatives, co-authoring acceptance criteria with customers and ensuring architectural considerations are captured in backlog stories before development begins
Serve as the client voice in customer architecture reviews, RFP responses, and proposal technical sections — representing client's SME depth on Twilio Voice and healthcare communications
What We're Looking For Required — Twilio Platform Expertise
5+ years hands-on production experience with Twilio Programmable Voice, Twilio Studio, and TwiML — at enterprise scale (not just POC or sandbox)
Deep, working knowledge of Twilio Studio Flow design : execution model, widget types, HTTP Request widget limitations, execution step limits, and the conditions under which Studio is and is not the right tool for a given problem
Expert-level TwiML authoring and the interaction between TwiML verbs and Twilio's execution model under load
Production experience with Twilio Webhook architecture : signature validation, async response patterns (to handle the 15-second hard timeout), status callbacks, recording callbacks, and idempotent webhook handlers
Hands-on experience with Twilio TaskRouter : workspace design, Worker/Queue/Workflow configuration, EventStreams integration, and replicating complex routing criteria from legacy ACD systems
Demonstrated experience designing DTMF fallback paths — handling fax tone detection (1100Hz), timeout/no-input retry loops, invalid-digit recovery, and graceful voicemail fallback under all failure conditions
Production experience with ASR failure recovery : confidence threshold tuning, multi-modal fallback (speech → DTMF), language-specific grammar considerations, and latency management for STT under clinical call profiles
Real-world knowledge of carrier redundancy patterns for Twilio: dual-carrier SIP trunking, geographic failover, DNS-based routing, and the operational differences between Twilio Elastic SIP and direct carrier interconnects — including patterns not in Twilio's public documentation
Required — Architecture & Engineering
3+ production Twilio migrations led from end-of-life on-premises telephony (Genesys, Cisco, Avaya, or equivalent) to Twilio-based cloud architecture — you have personally designed and delivered the target-state architecture, not just contributed to one
Strong proficiency in .NET (C# / ASP.NET Core) for Twilio Voice API backend services: webhook controllers, TwiML response generation, Twilio SDK usage, and integration with Redis for call session state
Experience designing and operating Redis-backed distributed state management for stateless webhook systems — specifically maintaining call context (ANI, DNIS, IVR selections, transfer history) across multiple webhook hops within a single call
Familiarity with AWS audio serving patterns for IVR: S3 object hosting, CloudFront CDN configuration, cache-warming strategies, and pre-signed URL generation for HIPAA-compliant prompt file access
Experience with multi-tenant IVR architecture at scale: 500+ simultaneous call flows, shared routing infrastructure, per-tenant configuration, and isolation patterns
Strong understanding of SIP protocol fundamentals — SIP trunking, DNIS/ANI manipulation, SIP headers, SIP-to-PSTN bridging, and the relationship between Twilio's SIP domain and downstream CUCM/PBX infrastructure
Required — Healthcare Domain
Healthcare communications experience — you understand the unique requirements of clinical telephony: on-call escalation chains, provider routing (not just ACD), clinical SLA expectations, and the patient safety implications of call routing failures
Working knowledge of HIPAA requirements as they apply to telephony: PHI in call metadata, call recording consent workflows (HITECH), audit trail requirements, and the difference between a HIPAA-compliant architecture and a compliant implementation
Experience designing for 24/7 mission-critical uptime in clinical environments — where a routing failure is not a business inconvenience but a potential patient safety event
Nice to Have
Experience with Genesys PureConnect (ININ) XML handler reverse-engineering or decommission
Twilio Flex and TaskRouter agent desktop configuration experience
Twilio Voice Intelligence or NLP-based intent routing (Twilio ConversationRelay, Autopilot, or custom ASR models)
Twilio Notify at scale — including rate limit architecture, priority queue dispatching, and mass-notification burst handling
Experience with number porting at scale (10k+ DID/toll-free numbers) including AT&T/Twilio porting coordination and FOC management
Hangfire or equivalent .NET background job orchestration for asynchronous notification dispatch
Experience building automated regression test frameworks for call flows — DTMF/ASR simulation, TwiML response assertion, CI/CD integration
AWS Lambda / CloudFront / S3 operational experience in a production IVR audio serving context
Familiarity with Twilio Event Streams and real-time operational dashboarding for call center/IVR observability
Prior experience in a vendor/consulting SME role — presenting architectural recommendations to customer technical and executive stakeholders