Senior Software Engineer, Full Stack

Postscript is the AI messaging platform trusted by over 20,000 Shopify brands, aiming to make SMS the top revenue-driving channel. They are seeking a Senior Fullstack Engineer to take ownership of systems, drive technical quality, and influence the organization's building standards while working with AI-driven development tools.

Responsibilities:

• Take deep ownership of systems and product areas on your team — becoming the go-to technical expert for what you own
• Independently investigate, design, and execute solutions across distributed systems with a high degree of ambiguity
• Architect, build, and maintain highly available, scalable REST APIs and backend services for internal and external use
• Drive system decoupling, modularization, and technical debt reduction — improving long-term maintainability without blocking near-term delivery
• Build agentically as your default: run multiple autonomous agents and worktrees in parallel (5+ is the benchmark), own the output, and keep a steady queue of aligned work moving
• Stay at the forefront of emerging AI tooling and practices, bringing new techniques back to the team and helping raise the floor for how Postscript engineers work
• Contribute to how we think about integrating AI into our systems and workflows — not just using AI tools, but helping shape where and how AI creates leverage across the engineering org
• Collaborate cross-functionally with product, data, and go-to-market teams — communicating clearly and proactively in an async-first environment
• Identify and eliminate single points of failure, improving system resilience and knowledge redundancy across your team
• Improve how engineering gets done: bring better tools, fix workflow friction, build internal utilities when the leverage compounds

Requirements:

• 6+ years of experience building large-scale backend systems and APIs
• You are an active, daily user of AI coding tools and are using them to maximize your output — Claude Code, Cursor, Copilot, or equivalent — and can speak concretely to how they've changed your output and your workflow
• Tech stack: Python, Go, React, and TypeScript; experience with Kubernetes, AWS, Datadog, and relational/NoSQL databases
• You follow the AI tooling landscape closely: new model releases, emerging agentic workflows, and evolving best practices aren't things you catch up on eventually — they're things you're tracking in real time
• You think critically about AI output — you know where it accelerates you, where it introduces risk, and how to verify what it produces
• You are able to context switch extremely quickly across concurrent workstreams
• Experience working on both 0-to-1 initiatives and complex existing systems — and knowing how to balance building new things with improving what's there
• Strong command of relational and NoSQL databases, SQL, and thoughtful database modeling
• Familiarity building and observing applications on AWS, and ideally with Datadog or comparable observability tooling
• Clear, direct communication — cross-functional partners and async teams can count on you to surface information proactively
• Strong instincts for technical tradeoffs informed by both engineering best practices and business priorities