Senior Back-End Developer

About The Company
Hercle is a fast-growing fintech building institutional-grade infrastructure that bridges fiat, stablecoins, and digital assets, enabling cross-border payments and banking infrastructure for global trade.

About The Company
Hercle is a fast-growing fintech building institutional-grade infrastructure that bridges fiat, stablecoins, and digital assets, enabling cross-border payments and banking infrastructure for global trade.

Serving over 200 clients globally, Hercle provides banks, brokers, payment service providers, fintechs, commodity traders, corporate treasuries, and other NBFIs with seamless solutions for cross-border payments and treasury management.

Working at Hercle
We're a lean, flat team where ideas matter more than titles and everyone gets real responsibility from day one. You'll solve complex problems at the intersection of global finance and digital assets, for some of the world's largest institutions and corporates. If you're curious, driven and excited to shape how money moves globally, we'd love to meet you.

About The Role
We're looking for a Senior Back-End Developer to join our Foundations & Reporting squad, which owns Hercle's technical foundations and information flow: the core ledger, balances, reconciliation and reporting, and the adapters that connect us to banks, custodians, venues and other providers.

Key Responsibilities

Design, build and maintain the double-entry ledger and balance services that are Hercle's source of truth

Scale the reconciliation engine that automatically matches our books against banks, custodians and venues

Build resilient adapters to banking, custody, exchange and stablecoin providers, including webhooks and deposit processing

Own the Reporting API and data feeds used by Finance, Data, auditors and regulators

Drive platform reliability: uptime, monitoring, logging, tracing and alerting across services

Write clean, documented code, review peers' work, fix bottlenecks and bugs, and improve CI/CD

How We Build
Every squad works on our two C# code bases: the Execution API, the client-facing gateway exposing documented REST and real-time WebSocket (SignalR) APIs, and the Back Office API, used daily by Operations, Compliance and the trading desk. Behind them sits a fleet of domain microservices and provider integrations.

.NET 10 microservices over gRPC; event-driven internals with CQRS, domain events and background jobs

AWS throughout: EKS, DynamoDB (in-memory caches on the hot path), Cognito, OpenSearch, S3

Azure DevOps CI/CD, with integration tests run against real deployed environments

AI-first engineering: agents write and refactor code, review every PR and help investigate incidents

What You Will Work On
You own the source of truth: what Hercle holds, where it holds it, and the systems that keep the two in agreement.

Core ledger, balances and transactions services that every trade and payment writes to

Adapters to banks, custodians, exchanges, stablecoin issuers and payment platforms

Idempotent webhook ingestion and deposit processing, resilient to provider outages

The reconciliation engine and position management system (PMS)

Reporting API and data feeds, plus platform reliability on Kubernetes

Requirements

Bachelor's degree in Computer Science, Engineering or a related technical field

5+ years building back-end systems in a strongly typed language (e.g. C#/.NET, Java, Kotlin, Go)

Strong grasp of OOP, design patterns, distributed systems, concurrency, multithreading and performance optimisation

Experience with SQL and NoSQL databases, CI/CD, Git and testing frameworks

Strong problem-solving, attention to detail and ownership in a fast-paced environment

Daily, hands-on use of AI coding agents on production work (not just autocomplete), with the judgement to give them the right context and to review and own what they produce

Fluent written and spoken English

Nice to have

Strong C#/.NET experience

Knowledge of Ledgers, accounting, reconciliation or financial reporting systems, and financial controls and audit requirements in a regulated environment

Experience with integrating custody, exchange or banking APIs and their webhooks

Familiarity with observability and SRE practice (OpenTelemetry, Prometheus, Grafana, ELK or similar) on Kubernetes