We need an English-fluent Senior Full-Stack Software Engineer, based in NY, preferable Manhattan.

We are looking for someone with exceptional communication and relationship-building skills, who embraces changes while maintaining strong attention to detail. An interested and proactive person, who's constantly learning and improving their skills.

Are you the one we are looking for?

Responsibilities:

• A TypeScript monorepo: a Next.js 16 web app and API, an Expo mobile app, and a Cloudflare Worker.

• A PostgreSQL + Prisma data model with dozens of models and a long migration history, shared across apps.

• Background systems: webhook handlers (Plaid, Stripe, Linq), queued inbound-message batching, and scheduled jobs.

• Security-sensitive paths: encrypted bank tokens and chat content, per-user data scoping, auth across web and mobile.

• The AI layer: LLM tool-calling over users' financial data, long-term memory, and proactive insights.

• Reviewing AI-generated code, including your own, with a skeptical eye.

Requirements:

• 6+ years as a software engineer, 3+ years shipping production TypeScript/Node backends.

• Shipped work at a company that moved money or handled bank or card data (Plaid, Stripe Treasury, Unit, Synapse-era BaaS, card issuing, lending, payroll).

• Deep PostgreSQL: migrations safe to run on live data, indexes, transactions, query plans.

• Real experience with async systems: idempotency, retries, deduplicating webhooks, jobs that fail halfway.

• A security-first instinct around PII, encryption at rest, auth tokens and least privilege.

• Solo ownership of production at least once: on-call, reading error tracking, writing root-cause analyses.

• Daily use of AI coding tools (Claude Code, Cursor or similar), and clear views on where they go wrong.

• Written English good enough that a PR description or incident write-up needs no follow-up questions.

It's a plus:

• Plaid in production: webhooks, item re-authentication, transaction sync cursors.

• LLMs in production: tool-calling, prompt evaluation, cost and latency control.

• Next.js App Router and React Server Components.

• SMS or messaging compliance (opt-outs, TCPA), or Stripe subscription billing.

• Expo / React Native.

Compensation:

• The salary range offered for this position varies from (USD) $9,200 - $10,000 per month, depending on seniority and skillset.

• This is a hybrid position with a flexible schedule, the days and times you’ll need to be in the office may vary depending on business needs

• This position is for a full time contract, through a payroll platform.

• The talent will work remotely allocated at our client.

Here are the steps for this process:

Application review/approval > Screening interview with GoFasti's team > We build and send your profile to our client > Profile review/approval by client > Interview with the client > Hiring and onboarding.