Senior Backend Engineer
First seen by Alion on Sep 25, 2026.
Senior Backend Engineer - Payments & Wallet
Location : Remote
Employment : Full-time
Experience : 7+ years, preferably including fintech/payments
About the Role :
We are looking for an exceptional Senior Backend Engineer specializing in payments and financial systems to join a small engineering team building and operating a regulated fintech platform.
You will take significant ownership of the systems responsible for moving and accounting for customer money.
This is a senior engineering role with substantial responsibility for transaction integrity, reliability and financial correctness.
What You Will Build and Own :
- Digital wallets
- Financial ledger
- Payment processing
- Salary payment processing
- Payment gateway integrations
- Bank integrations
- Remittance integrations
- Merchant payments
- Withdrawals
- Refunds and reversals
- Transaction limits
- Settlement
- Reconciliation
- Transaction history
- Financial reporting
- Internal operational tools
Responsibilities :
- Design and develop reliable backend services
- Build and maintain financial transaction workflows
- Maintain ledger integrity
- Design transaction state machines
- Implement idempotent APIs and transaction processing
- Handle payment failures, retries and duplicate callbacks
- Implement refund and reversal mechanisms
- Build settlement and reconciliation services
- Integrate banks, payment providers and other financial institutions
- Design scalable database structures
- Build automated reconciliation controls
- Develop monitoring and alerting around financial transactions
- Write comprehensive unit and integration tests
- Participate in architecture and code reviews
- Investigate and resolve production incidents
- Maintain complete auditability of financial transactions
Required Experience :
- Strong backend engineering experience using modern backend technologies.
- Excellent understanding of :
1. SQL/PostgreSQL
2. Relational databases
3. API design
4. Distributed systems
5. Database transactions
6. Concurrency
7. Message queues
8. Event-driven systems
9. Caching
10. Authentication and authorization
11. Secure coding practices
Financial Systems Knowledge :
We strongly prefer candidates who understand :
- Digital wallets
- Double-entry ledgers
- Payment processing
- Transaction lifecycle management
- Settlement
- Reconciliation
- Refunds
- Reversals
- Idempotency
- Financial audit trails
Experience building production systems at a fintech, bank, payment gateway, wallet, acquiring company or payment processor is highly desirable.
The Type of Engineer We Want :
We are not looking for someone who simply implements API specifications.
We want an engineer who asks :
- What happens if the payment provider processes the transaction but our server never receives the response?
- What happens if we receive the same callback twice?
- How do we prove that the customer's balance is correct?
- How do we reconcile our ledger against an external payment provider?
- How do we safely recover from a partial failure?
If these are the types of engineering problems you enjoy solving, we would like to speak with you.
Skills
SQL, PostgreSQL, Distributed Systems, API, Payment Gateway, Payment Processing