Sean Trantalis
Staff Architect | Software architecture & product engineering
Profile
I’m a staff architect who enjoys making complicated systems simpler. My career has taken me through building applications, running infrastructure, and leading engineering teams. That experience shapes how I work: I want to understand what we’re building and why, work through the technical decisions, and help turn them into working software.
Technical expertise
- Engineering
- Go, distributed systems, software architecture, SDKs, developer platforms
- Platform engineering
- Kubernetes, Istio, OpenShift, AWS, GCP, Terraform, Argo CD, GitOps
- Security
- OIDC, ABAC, key management, HSMs, data-centric security
Experience
Staff Architect II
Virtru
- Led the consolidation of Python and Go services into a modular Go platform for on-premises and disconnected deployments. Individual services could still run separately.
- Architected three key-custody modes for local, database-held, and external-provider keys. Led AWS KMS, Google Cloud KMS, Thales, and nShield integrations.
- Implemented Go SDK encryption for out-of-order S3 multipart uploads without buffering gigabyte- or terabyte-scale objects, now used by an S3 proxy in Virtru's SaaS platform.
- Built a Go WebAssembly cryptography module for browser encryption, supporting RSA, ECDH, and post-quantum cryptography.
- Proposed an internal CBOR-based binary TDF specification. Implemented the Go core with key splitting and streaming support.
- Helped a five-engineer team ship a secure collaboration product in roughly one quarter, with ABAC workspaces protected by TDF in Virtru's SaaS platform.
- Created the first ADR template and repository. Helped establish the review process used across engineering, SRE, and security.
Senior DevOps Engineer II / DevOps Manager
Virtru
- Led a GitOps migration of at least 10 microservices from EC2 to EKS across four AWS accounts, introducing Istio and per-cluster Argo CD.
- Built an Istio external authorization service for legacy App ID, HMAC, and OIDC credentials, removing validation from application code.
- Built cross-cloud networking and workload identity for the EKS-to-GKE migration, preserving access to DynamoDB, Elasticsearch, and RDS on AWS.
- Managed a three-person platform team. Contributed to FedRAMP readiness and annual disaster recovery and incident response exercises.
Cigna
IT Principal (Senior Staff Engineer) | Cloud Architecture & Engineering
Infrastructure Engineer
Software Engineer
- Led the OpenShift 3-to-4 migration across four data centers; all mission-critical applications in scope ran on two production clusters by departure.
- Built self-service namespace provisioning and workload placement using Prometheus metrics.
- Grew the OpenShift team from one engineer to more than 10 across engineering, support, and operations.
- Architected a multi-data-center Red Hat Quay registry with image replication and a read-only production endpoint for site outages.
- Built a Java and Spring Boot wellness platform adopted across Cigna and customer organizations. Helped move delivery to Elastic Beanstalk and RDS.
- Built an offline voice navigation prototype for myCigna using C++, CMU PocketSphinx, and iOS and Android bindings through Dropbox Djinni.
Independent product
Ask Gill
Designer and solo engineer | 2025 - now
- Designed, built, and launched Ask Gill independently for iOS and Android. Developed the app and backend, managed store releases, and handled subscriptions, customer support, and marketing.