Senior Backend Engineer — Vendor Payments

Vantaca+HOAi•Redwood City, CA

4d•Remote

About The Position

HOAi is a fast-growing startup revolutionizing the community association management industry. Our AI workforce platform integrates machine learning technology to streamline labor-heavy processes, eliminating inefficiencies and driving scalability. With rapid growth in the AI space, we are pushing boundaries to redefine industry standards. HOAi is the leading AI solution for the community association management industry, enabling organizations to deploy AI Agents that function like experienced managers. These AI Agents go beyond traditional AI by proactively executing complex, multi-step processes with human-like reasoning—working autonomously, 24/7, across your entire operation. This transformation optimizes labor costs, enables growth without additional hires, and ensures faster, higher-quality service for residents and board members. HOAi was acquired by Vantaca in the fall of 2024. Vantaca just achieved unicorn status with a $1.25B valuation, so it's safe to say we're past the "scrappy startup phase." We're not just building a successful company – we're building the category-defining platform that will transform how an entire industry operates. Here's the reality of our trajectory: Growing 100% year-over-year Our AI product (HOAi) went from $0 to millions in months Backed by Cove Hill Partners and JMI Private Equity 6M+ doors on our platform, displacing legacy systems About the role We’re building a modern payments platform that reliably processes high volumes of transactions end-to-end. This role owns backend systems that move money, reconcile ledgers, integrate with external payment/banking partners, and meet a high bar for correctness, security, and uptime.

Requirements

6+ years building backend systems in production environments with real operational responsibility.
Strong API design and data modeling skills (schemas, migrations, indexing, transactionality).
Experience designing distributed systems with queues/workers, event-driven patterns, and failure handling.
Proven ability to operate high-availability services: monitoring, alerting, incident response, and postmortems.
Comfort working in a high-velocity environment while maintaining a correctness-first mindset.

Responsibilities

Build core payment services: authorization/capture, refunds, voids, disputes/chargebacks, payouts, and settlement flows.
Design a robust ledger: implement double-entry (or equivalent) accounting primitives, reconciliation pipelines, and audit-ready data models.
Integrate with payment providers: build and maintain integrations with PSPs, gateways, processors, and risk/fraud services; handle webhooks and event streams.
High-scale reliability: implement idempotency, retries, exactly-once/at-least-once semantics where appropriate, backpressure, and safe concurrency.
Observability and operations: build metrics/tracing/logging for payment lifecycles; run incident response; improve SLIs/SLOs and on-call hygiene.
Security and compliance-minded engineering: secrets management, least privilege, encryption, PCI-adjacent controls, and robust access/audit trails.
Performance and cost: optimize throughput and latency across workflows; tune queues, databases, and caching for peak traffic.

Benefits

Our eNPS is +68! (Google it, that is great).
Benefits: Medical, Dental, and Vision kick in day one.
Unlimited PTO (with a requirement for employees to take a minimum of one continuous week per year).
401K with Company Match.
Remote Flexible - come to the office when needed.
Great parental leave benefits.
Named on Inc 5000 list of America’s Fastest Growing Private Companies.
Named on Inc 5000 Vet 100 Private Companies list multiple years in a row.
Winner of Coastal Entrepreneur Award, Technology Category.
Active employee-led Culture Committee.
Ongoing industry and professional development trainings available to all employees.
Multiple leaders on the executive committee recognized as 40 under 40 recipients for contributions to business and community.
We’re playing offense to win! Our product market fit and our world-class employees make us the leader in our space. We’re building something cool and people like it here.