Candidate portfolio
Chad Koslovsky · Candidate portfolio
OpenAI · Full Stack Software Engineer, Codex
I’m a product engineer and founder who helps companies turn messy workflows into software people can use. My freelance practice spans interfaces, APIs, AI integrations and production operations. I work directly with clients and teams, build the tools behind the product, and stay responsible after launch.
CRUCIBLE.EXEI attended the recent OpenAI DevDay and completed CRUCIBLE.EXE for the Codex Chromatic release. The project connects a pixel-art engine pipeline to a native cartridge, playable website and public source, with an inspectable build and test workflow.
Attended the recent OpenAI DevDay. Built a native Game Boy Color game with Codex and Claude, a portable C rules core and TypeScript build tools. Connected the pixel-art pipeline to cartridge assets and a playable website; pinned the toolchain and added headless PyBoy checks of screen output and memory.
I’m building an AI product for kids entrepreneurship. The product starts with a child’s idea and helps turn it into an approachable small-business experiment. It is an active concept and build, with the child’s creativity and decisions at the center.
Building an AI product for kids entrepreneurship that helps turn an idea into a small-business experiment while keeping the child’s creativity and decisions central. Active product concept and build.
I created Velatis for a client and completed my work on the product. The private research workspace combines deterministic chart tools, context-aware AI, notes, identity, sharing and payments with explicit data and ownership boundaries.
Created a private research workspace for a client, spanning identity, notes, sharing, payments and context-aware AI. Built deterministic chart tools and typed, embeddable services with explicit privacy and ownership boundaries.
Frontend: TypeScript, JavaScript, React, Next.js, Vue, HTML and CSS. Backend and data: Node.js, Python, Rust, PostgreSQL, SQL, MongoDB, Redis, REST, GraphQL, tRPC and webhooks. AI and developer tools: OpenAI APIs, prompt design, MCP servers, tool orchestration, retrieval and embeddings, structured outputs, evaluation, Git and GitHub Actions. Cloud and reliability: Linux, AWS, Docker, Kubernetes, Terraform, Ansible, CI/CD, monitoring, incident response and disaster recovery. Product and security: client discovery, workflow design, OAuth/OIDC, PKCE, SAML/SCIM integrations, tenant-aware access controls, billing and subscriptions.
Designed, built and operated a Node.js Amazon reseller platform: marketplace and competitor-data ingestion, rules-based repricing, monitoring, analytics, accounts, subscriptions and in-product support. The product was acquired.
Completed my contribution to a client’s open-source document-signing platform using Next.js, React, tRPC, Drizzle and PostgreSQL, plus a Rust verification and PDF engine. Implemented signing routes, authentication, audit trails, encrypted vaults, webhooks and embedded signing.
Freelance engineering, client delivery and production responsibility across five roles.
Grew freelance work into a referral-based technical practice serving SaaS, security, web, crypto and affiliate clients. Usually the only or lead engineer, own discovery through deployment and support with React, Vue, Next.js, TypeScript, Node.js, PostgreSQL and Redis. Built Blade Construction’s ticketing and CRM workflow; managed Excell Services’ IT function and modernized network and recovery systems for roughly 30 employees. Built tenant-aware support workflows spanning CRM, scheduling, billing, telemetry and AI, with MCP connectors and OAuth/OIDC integrations. Collaborated with TokenGators and Bitlectro Labs on applications, marketplace integrations, automation and launches.
Led the NOC team and on-call escalations; owned monitoring, incident response, client migrations and recovery verification. Migrated Nagios to Zabbix and modernized workloads with Docker and Kubernetes. Codified infrastructure and release workflows with Terraform, Ansible and CI/CD. Led technical readiness for SOC 1/SOC 2 audits, working with auditors on control evidence, backup testing and engineering SOPs.
Built SQL- and MongoDB-backed internal applications connecting CRM, provisioning, onboarding and service operations across departments and locations.
Managed SMB networks, monitoring and incident response; built diagnostic automation and worked directly with business owners and end users.
Supported enterprise infrastructure for Best Buy, Amtrak and USPS; automated audit, backup and compliance workflows and coordinated access, changes and incidents across teams.