Senior / Staff Full-Stack Engineer (Node.js + AWS)

About Blue Language Labs

Every generation gets one protocol moment. TCP/IP. SMTP. HTTP. A small team writes the spec, ships the first implementation, and fifteen years later the entire world runs on it without knowing who built it. We're at that moment for economic coordination.

AI agents are being deployed everywhere, right now - negotiating, committing, paying, settling on behalf of every company that wants to stay competitive. In a few years there will be billions of them. The problem: there is no protocol for what happens between them. An agent can be smart. It cannot be governed. It can pay. It cannot make a payment conditional on something that actually happened. Agents from different organizations can talk. They cannot safely coordinate across company boundaries.

Nobody has built that layer. We're building it.

Blue is a protocol for structured, verifiable, multi-party agreements that execute deterministically, leave an immutable audit trail, and run on existing financial rails. Smart contracts without blockchain. Governance without a platform. Trust without a middleman.

• PayNotes - programmable payments with conditional capture, milestone releases, automatic refunds, and partner settlement. Logic embedded directly into money movement.

• MyOS - orchestration layer for merchants and agents. Agentic workflows and cross-platform trust, without touching the protocol directly.

The Role

You will own features end-to-end - from the React component a merchant clicks to the Lambda function that settles their transaction to the AWS infrastructure that keeps it all standing. No handoffs between "front" and "back". No waiting for someone else to unblock you.

This is a high-trust, high-autonomy role. You'll work directly with the founding team, your decisions will ship to production fast, and yes - you'll be on the hook when something breaks.

What you get?

• Competitive B2B compensation based on experience

• Equity - own a piece of what you build

• Fully remote work in an async-first environment

• Direct collaboration with the founding team

• High autonomy and fast decision-making

• Small team, outsized impact

• Work on technology that is genuinely novel

• End-to-end ownership across product, systems, and production

Protocols don't get built by committees. They get built by small teams who understood the problem before anyone else did.

What You'll Do

• Design and ship full-stack features across payments, document workflows, and agent orchestration

• Build and maintain stateful systems that demand idempotency, auditability, and safe retry logic

• Own AWS infrastructure - architecture decisions, serverless systems, IaC (SAM / CloudFormation), monitoring, cost, and security

• Work with PostgreSQL-backed services and event-driven components

• Use modern AI tooling (LLMs and coding agents) to accelerate development and experimentation

Requirements

We're not looking for someone to fill a seat. We're looking for an engineer who gets it - who sees a distributed system and immediately starts asking the right questions about state, consistency, and failure modes. Someone who ships and takes pride in what they ship.

• 7+ years of experience building and shipping production systems as a full-stack engineer

• Strong backend expertise in Node.js and TypeScript - not just building APIs, but designing systems that stay correct under load and failure

• Strong frontend skills with React, including the ability to build polished, production-ready product interfaces without depending on a separate frontend team

• Solid understanding of distributed systems: consistency, state transitions, concurrency, retries, failure handling, and eventual consistency trade-offs

• Proven experience building stateful, event-driven systems where correctness matters

• Hands-on experience with AWS in production, especially Lambda, API Gateway, SQS/SNS, EventBridge, IAM, CloudWatch, RDS, and serverless architecture patterns

• Strong experience with Infrastructure as Code, ideally AWS SAM and CloudFormation

• Strong PostgreSQL skills, including schema design, transactions, indexing, migrations, and performance tuning

• Experience designing systems with idempotency, auditability, and deterministic execution built in from the start

• Ability to debug and stabilize production systems end-to-end - across application code, infrastructure, data, and runtime behavior

• Strong grasp of observability, monitoring, logging, alerting, and incident response

• Good judgment around security, reliability, and cloud cost, with the ability to make pragmatic architectural trade-offs

• Ability and willingness to own features end-to-end - from product shaping to implementation, deployment, and post-release accountability

• Comfortable operating in a high-trust, high-autonomy environment with very little hand-holding

• Strong product and engineering judgment - you ask the right questions early, and you do not need heavy process to move fast responsibly

• Comfortable using LLMs, coding agents, and modern AI tooling as part of your development workflow

• Fluent English and Polish, written and spoken

Nice to have

• Experience in payments, fintech, ledgering, settlement, or transactional systems

• Experience with document workflows, approvals, or multi-party business processes

• Experience working on systems of record or products with strict audit/compliance expectations

• Experience at an early-stage startup or in a small, high-talent engineering team

• Experience building products where reliability and system correctness matter more than shipping surface-level features

A process that is practical, clear, and respectful of your time

We keep the sequence focused so both sides can understand fit, technical quality, and the shape of the work.

• Introductory conversation - Up to 60 minutes - A practical conversation about your background, the kind of work you want to do next, and the context behind the role.

• Take-home assignment - No live coding - We prefer to evaluate technical ability through a realistic take-home task that gives you time to think and show the quality of your approach.

• Technical interview - Up to 90 minutes - A deeper discussion with a technical leader or senior team member about your experience, engineering judgment, and approach to the assignment.

• Final review - Clear feedback and a timely decision - We gather feedback, review the process carefully, and aim to communicate clearly throughout.