Remote Senior Backend Ledger Engineer — Exact-Once

Financial Infrastructure, Inc.; Northern (KY); Hybrid; USD 120,000 - 180,000; Full time

Job summary

Financial Infrastructure, Inc. is seeking a senior backend engineer to own the ledger subsystem for the A8 Core platform. You will design and implement services in .NET that guarantee exact-once posting, correct balances, and scalable performance under load.

Remote work within the United States is available. You will collaborate with Compliance and Engineering to ensure auditability and reliability of the dual-entry ledger across deposits, transfers, and directives.

Qualifications

• 6+ years building backend services in production, with significant time on systems where correctness is non-negotiable.
• Strong .NET / C# and relational data modeling (SQL Server or PostgreSQL).
• Deep, practical understanding of idempotency, concurrency, transactions, and consistency.
• Experience with financial ledgers, payments, or other transaction-of-record systems.

Responsibilities

• Design and build ledger services on .NET 10 that post transactions correctly and idempotently.
• Guarantee exactly-once posting and consistent balances under concurrency and retries.
• Implement reconciliation and integrity checks against funding rails and account state.
• Write the append-only evidentiary record alongside every state change, keyed to the RequestId.
• Partner with Compliance on the audit and reporting needs the ledger must satisfy.
• Hold the correctness bar through rigorous testing, property-based checks, and code review.

Skills

C#

.NET

SQL

Concurrency

Idempotency

Tools

ServiceStack

PostgreSQL

Job description

Financial Infrastructure, Inc. is seeking a senior backend engineer to own the ledger subsystem for the A8 Core platform. You will design and implement services in .NET that guarantee exact-once posting, correct balances, and scalable performance under load.

Remote work within the United States is available. You will collaborate with Compliance and Engineering to ensure auditability and reliability of the dual-entry ledger across deposits, transfers, and directives.