Resume

Calleum - github.com/calleum - Sydney, Australia

Systems engineer: now writing Rust (SimConverse). Before that, ~4 years of Java enterprise platform work (Protecht). Building a PostgreSQL-style storage engine in C with a coverage-guided fuzzer after work.

Experience

SimConverse - Software Engineer (Rust)

December 2025...present: Sydney, Australia

• Rust/axum/sqlx backend engineer on a healthcare conversation simulation engine; also Vue 3 frontend work (Ada), Helm charts, and CI.
• Rewrote the real-time conversation engine as a native Rust/Socket.IO pipeline: explicit conversation state machine, unified audio/video pipelines, and streaming provider clients with bounded admission, connection pools, deadlines, and cancellation.
• Built a warm-standby GPU inference platform connecting AWS services to self-hosted and cloud GPU capacity: k3s cluster automation, Tailscale networking, shared multi-cluster Helm templates, DNS-aware gRPC load balancing, model readiness checks, graceful draining, and a capacity-aware gateway that queues clients and leases backend slots.
• Added customer-managed SSO on AWS Cognito: regional infrastructure, organization-scoped clients with tenant isolation, self-service SAML/OIDC provider configuration, native passwordless login, and transaction-safe identity conflict recovery.
• Built full-stack PR preview environments: per-change ECS services, logical databases, SSO clients, with scheduled expiry.
• Added request-scoped tracing that survives queues, background tasks, and gRPC boundaries; searchable Kubernetes logs, Sentry integrations, and incident dashboards.

Protecht - Software Developer (DevOps Engineer to Jun 2022)

December 2021...November 2025: Sydney, Australia

• Java microservices on an enterprise risk/compliance platform serving >350 tenants.
• DevOps first (Kubernetes, AWS, HAProxy), then full-time development.
• Architected and executed a zero-downtime 1.6 TiB postgresql migration of >200 databases to AWS via pglogical and ansible.

Darumatic - Consultant (Kotlin / DevOps)

April 2021...December 2021

• AWS CDK infrastructure, PDF generation pipelines, API integrations.

Open source

mosken - pg-style storage engine

C ; personal project ; ongoing

• Slotted-page storage layer modeled on PostgreSQL heap pages: page allocation, tuple insert/update paths, free-space management.
• Coverage-guided fuzzing harness for the page layer — crash-consistency and out-of-bounds cases.
• Companion PostgreSQL internals study (buffer manager, WAL, MVCC).

Other

fennel-language-server (Rust), others.

Skills

Rust, C, Java/JVM, Kubernetes, AWS, PostgreSQL (production usage + internals study)

Linux, CI/CD

Strong in observability and on-call operations

Education

Macquarie University - BEng (Honours), Software Engineering (expected)