Senior Software Engineer – Full-Stack & Cloud Infrastructure

Senior Software Engineer - Full-Stack & Cloud InfrastructureWe're looking for a senior engineer who likes owning things end to end.Take an idea from a whiteboard to a working proof of concept, then through to a production system that people depend on.Move between rapid prototyping and production hardening as needed.Own infrastructure, CI/CD, observability, and security alongside application development.Work directly with leadership in an environment with no separate DevOps handoff.Spec-driven development - write requirements, design, API contracts, data models, and correctness properties before coding.Rapid prototyping - turn a business idea into a working proof of concept quickly, while keeping it structured enough to scale.Production delivery - harden prototypes, provision infrastructure, build pipelines, promote through Dev, QA, Staging, and Production, and maintain stability after launch.Backend services - build REST APIs, background workers, data pipelines, and integrations with Microsoft 365, Salesforce, AI/LLM providers, and payment systems.Cloud infrastructure - manage AWS resources written as Terraform across multiple environments.CI/CD pipelines - build automated build, test, scan, deploy, and rollback workflows.AI and LLM integrations - connect LLM APIs into product workflows, including prompt design, structured output handling, confidence scoring, and cost tracking.Agentic AI systems - design AI agents with multi-step reasoning, tool use, structured outputs, human-in-the-loop checkpoints, and graceful handling of uncertainty.Observability - implement structured logging, custom metrics, health checks, and alerting.Frontend - work with React, Next.js, or TypeScript-based frontends as needed.This is what the day-to-day work actually looks like, so be honest with yourself about whether it fits.Backend: Strong in at least one backend language - Python or Node.js/TypeScript - and able to pick up the other when needed. Able to write production-grade code with async patterns, strong typing, explicit error handling, structured logging, and stable REST APIs with proper HTTP semantics and server-side auth enforcement.AWS: Experience provisioning and operating ECS Fargate, RDS, ALB, ECR, IAM, Secrets Manager, and CloudWatch in production. Able to manage Terraform with proper environment separation, remote state, and module structure.Containers and CI/CD: Experience building production Docker images with multi-stage builds, non-root users, health checks, and image scanning, plus CI/CD pipelines in GitLab CI or GitHub Actions with automated deployment, rollback, and no long-lived credentials.Agentic AI: Understands tool-calling or function-calling workflows, structured prompting, uncertainty handling, and human-in-the-loop design, especially in high-stakes environments like payments. Experience with LangChain, LlamaIndex, Strands, or custom agent loops is relevant.Security: Comfortable with parameterized queries, secrets managers, least-privilege IAM, and input validation at the API boundary.Testing: Writes meaningful unit, integration, and property-based tests that catch real regressions.Nice to have: Datadog APM and custom metrics, enterprise OAuth2 integrations such as Microsoft Graph and Salesforce, LLM API experience with Anthropic or OpenAI, and OIDC-based CI/CD auth to AWS.Work spec-first by writing requirements, designing solutions, and agreeing on the approach before major feature development.Contribute directly to design docs and correctness thinking rather than only implementing handed-off work.Thrive in a small, high-trust team with direct communication, low ceremony, and high autonomy.Raise concerns early, give honest feedback, and collaborate closely with leadership and about both speed and quality, with a focus on software that works well and avoids future problems.Speak up when something should be done differently, because individual opinions have real weight on a small team.Employment Type: Contract-to-hireExperience: 7+ years in a professional software engineering roleLocation: Hybrid, NYC basedCompensation: