Backend Engineer - AWS Serverless Platform

Arcault is an early-stage financial wellness platform helping employees plan for life’s biggest milestones through guided digital journeys and AI-assisted workflows. We’re building a secure, trustworthy, and AI-native benefits platform in a sensitive financial domain.

We’re looking for a Platform Engineer to join the team where they will evolve the backend and infrastructure foundations as we move from MVP to production usage. We’re especially excited about engineers who bring a growth mindset—people who are curious, reflective, and eager to learn new ways of building with AI as the tooling and best practices evolve. This role is hands-on and broad in scope: backend services, cloud infrastructure, operational readiness, and secure-by-default systems.

You’ll work closely with a small, hands-on leadership team, contributing to technical direction while actively building and shipping production systems. Early hires at Arcault have meaningful impact, and we’re deliberate about building the right foundations from the start.What you’ll do

• Build and evolve backend services on AWS serverless (Lambda) using JavaScript/TypeScript, contributing to API design, workflows, and data access patterns.
• Take ownership of defined backend and platform areas—shipping, operating, and improving them over time.
• Learn and iterate on emerging AI development patterns—experimenting responsibly, evaluating tradeoffs, and helping the team establish best practices over time.
• Continue to evolve our engineering foundations: CI/CD, infrastructure-as-code, automated testing, observability, and operational practices.
• Contribute to secure-by-default systems, including least-privilege IAM, secrets management, encryption, dependency hygiene, and pragmatic threat modeling.
• Build backend primitives that enable AI-assisted workflows (e.g., event capture, audit logs, permissions, safe execution), with an emphasis on reliability and trust.
• Take initiative and own outcomes within your scope, while actively pairing, reviewing, and learning alongside a small, hands-on team.

Requirements

Minimum qualifications

• 3+ years building and operating backend systems in production environments, with clear ownership of shipped services.
• Strong experience with JavaScript/TypeScript (Node.js) and modern backend patterns (APIs, async workflows, data access).
• A growth mindset: curiosity, openness to feedback, and enthusiasm for learning new tools and approaches—especially as AI changes how software is built.
• Hands-on experience with AWS, especially serverless architectures (e.g., Lambda).
• Practical DevOps experience, including CI/CD pipelines, infrastructure-as-code, monitoring/alerting, and operating services you’ve built.
• A security-aware mindset, including familiarity with IAM, secure data handling, dependency hygiene, and common application security risks.
• Strong engineering judgment and communication skills; comfort working in ambiguous, early-stage environments.

Nice to have

• Experience with or interest in event-driven systems (queues, streams) and distributed tracing.
• Exposure to AI-enabled systems (LLMs, RAG, tool/function calling, evaluation), or a strong desire to learn and build with AI responsibly.
• Familiarity with sensitive or regulated data domains (e.g., financial, legal, identity).

Don’t worry if you don’t check every box—we care more about sound judgment, learning ability, and ownership mindset.

Benefits

Benefits

• Competitive salary and meaningful equity (stock options).
• Medical benefits and 401(k) with company match.
• Flexible time off.
• Hybrid work model (Boston-based, at least 2 days per week in office), with in-person time focused on collaboration, pairing, and design discussions.
• Opportunity to grow with an early-stage company and have real impact on product, systems, and culture.