Full-stack Developer(for our partner group) Offline

Fyst 🔥
$$$
Product

About the role

No legacy, no bureaucracy, — just you and a small but incredibly strong engineering team making the right technical decisions together. A chance to go deep into fintech (card payments, compliance, settlement) and actually shape the product architecture.
 

Finance focus. This role is for our Finance direction: settlements, reconciliation, bank integrations, and integration with the core banking system. You'll go deep into the money flow — how funds move, settle, and reconcile across gateway, processor, schemes, and banks.
 

Fintech experience is essential. We need someone who already knows payments and fintech — this isn't a domain to pick up on the side. We expect proactivity and a readiness to take on and own the domain expertise: be the person the team relies on for settlement and reconciliation logic.
 

Important: we need a strong engineer with deep technical background. The engineering team is top-tier, and the bar is high. We're not looking for average — we're looking for people who can make decisions independently and own the outcome.
 

What you'll do:
 

Backend (Kotlin)

 

  • Financial Core: double-entry ledger (immutable), settlement engine (MDR calculation, netting, payouts), pricing engine (IC++/blended), rolling reserve management
  • Integrations: REST API integrations with payment gateway, card processor, KYC/KYB, SEPA/SWIFT payouts
  • Webhook processing: ingestion and processing of vendor webhooks
  • BPMN workflows: Camunda 8 — service tasks, user tasks, DMN decision tables for business processes (merchant onboarding, AML investigation, dispute management, settlement)
  • Compliance: transaction monitoring rules, sanctions screening integration, SAR workflow
  • API: REST API for merchant portal and ops panel
     

Frontend (Next.js)

 

  • Merchant Portal: dashboard (transactions, volumes, conversion), settlement history, payouts, chargebacks, API keys, webhook settings, onboarding wizard
  • Ops Panel: case management (AML, disputes), treasury dashboard, compliance dashboard, underwriting, merchant management
  • Developer Portal: API documentation (OpenAPI), integration guides, sandbox
     

General

 

  • Reconciliation: multi-layer reconciliation engine (gateway ↔ processor ↔ scheme ↔ bank ↔ safeguarding)
  • Reporting: regulatory reporting, scheme reporting (Visa/MC), financial (P&L)
  • Testing: we're AI-first when it comes to testing — fully automated coverage at every level: unit, integration, E2E. No manual QA — you write code, you write tests. E2E tests for the full payment flow (auth → capture → settlement → payout), integration tests with vendors, BPMN process tests via Camunda API


Requirements:
 

Must have

  • 6+ years of Kotlin or Java (Spring Boot) — REST APIs, JPA/Hibernate, transaction management
  • 3+ years of Next.js / React — SSR, TypeScript, state management
  • PostgreSQL — queries, migrations, indexes, JSONB
  • REST API design — versioning, error handling, idempotency
  • Git, CI/CD
  • Webhook processing, event-driven architecture
  • Okta / OAuth2 / OpenID Connect

 

Fintech / payments experience — a must, not a nice-to-have: settlements, reconciliation, bank integrations, integration with a core banking system

 

AI-fluency — active integration of AI tools (Cursor, Claude Code, Codex) into daily engineering work. Not just "aware of AI" — uses it to multiply productivity, with a critical eye for generated output

 

Proactivity — identifies problems before they surface, proposes solutions, drives them to done. Doesn't wait to be told what to do

 

English: confident reading and listening is a must. Good spoken English is a strong plus
 

Nice to have:

  • Understanding of double-entry accounting
  • Camunda / BPMN experience
  • Tailwind CSS, shadcn/ui

Required skills experience

Java 8 6 years
Kotlin 6 years
Spring Boot 3 6 years
Next.js 15 6 years
TypeScript 6 years
PostgreSQL 5 years
AWS 5 years

Required domain experience

Fintech 6 years

Required languages

English B2 - Upper Intermediate
Ukrainian Native

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