Backend Engineer

About Expert Listing
Expert Listing is a Lagos-based proptech startup building Nigeria's most trusted property marketplace - verified listings, live location maps, flood-risk indicators, and two years of historical pricing data, all aimed at one goal: help people find a fair deal in three clicks, not months. We're now extending the platform with an in-app wallet that supports both traditional and crypto payments, and we're looking for a Backend Engineer to help build it right.
The Role
You'll be one of the core engineers on Expert Listing's backend, with a specific focus on our new wallet and payments infrastructure, including crypto payment support. This is greenfield, security-sensitive work - you'll be shaping how money (and crypto) moves through our system from day one.
Responsibilities
- Design and build the wallet/ledger system: balances, transactions, holds, and reversals
- Integrate crypto payment rails (for example stablecoin payments) alongside traditional card and bank payments
- Build reliable, idempotent payment processing that survives retries, duplicate webhooks, and partial failures
- Work on fraud prevention, rate limiting, and basic compliance controls for a wallet handling real money
- Design and maintain core backend services and APIs beyond payments: listings, verification, pricing data
- Collaborate with the founder and frontend team on API contracts and system design
What We're Looking For
- Strong backend experience (Node.js, Python, or similar) with real production systems
- Experience with payments, ledgers, or other systems where correctness and auditability matter
- Comfort with, or strong interest in, crypto/blockchain payment integration
- A security-first mindset - you assume things will fail and design for it
- 3+ years of professional experience; fintech, payments, or crypto background is a strong plus
How To Apply
Send your CV and GitHub/portfolio to recruitment@expertlisting.ng with the subject line "Backend Engineer - [Your Name]". Please include your response to the assessment below with your application.
Soft Assessment (required, written - no code needed)
Expert Listing is adding a wallet that lets users fund an in-app balance and pay for things (verification fees, subscriptions, agent commissions) using both card/bank rails and crypto (for example stablecoins). In 300-500 words, walk us through how you'd think about the backend for this:
- How would you design the ledger so a user's balance is always correct, even if a payment webhook arrives twice, arrives late, or never arrives at all?
- Would you hold user crypto directly, or lean on a third-party processor or custodian - and why?
- What's the one failure mode in a crypto payment flow that worries you most, and how would you guard against it?
- How would you think about fraud controls and compliance for a wallet handling real money in Nigeria?
We're not looking for a textbook answer. We want to see how you reason about money moving through a system you don't fully control.

Work arrangement
No