Kamipay - Sr Backend Engineer (Python)

From Silver.dev

We are looking for outstanding talent looking to make an impact and be a technical leader at a highly critical payment infrastructure engineering organization.

The compensation listed is estimated and heavily based on concrete experience in the industry and in systems that handle money critically.

About KamiPay

Mission

Build and scale kamiPay core solution powering real-time cross-border payments via blockchain and RTP systems like Pix and Transferencias 3.0.

Key Focus

We seek a proven Senior BackEnd Software Engineer who has architected, developed, deployed, and maintained mission-critical systems handling high transaction volumes (e.g., fintech, banking, or distributed platforms). You must demonstrate experience scaling systems from early-stage MVP to production-grade reliability and have a track record of solving scalability, latency, and resilience challenges.

Why Join kamiPay?

• Solve hard problems at the intersection of blockchain and real-time payments across multiple countries.
• Work with a team that’s shipped production-grade fintech systems (no “theoretical” engineering).
• We have Product Market Fit: If you heard the word Pix in Argentina, it's because kamiPay introduced it to the market.

Technical Skills

• 7+ years of BackEnd development with Python (async frameworks like FastAPI, Django) and SQL.

• Strong expertise in designing RESTful APIs for high-traffic systems (1k+ TPS) with strict SLAs.

• Hands-on experience with cloud architectures (AWS preferred: ECS, Lambda, RDS, SQS/SNS).

• Proven ability to build async task processing (Celery, Redis) for real-time payment transactions, reconciliation, fraud checks, or batch processing.

• Good DevOps Practices: CI/CD (GitHub Actions), IaC (Terraform), and monitoring (Sentry, Cloudflare, Cloudwatch, Prometheus, Grafana, Datadog).

• Observability-Driven Development: Built systems with observability "baked in" (custom Sentry tags, structured logging, metrics for business-critical transactions).

• Hands-on experience with error-tracking tools like Sentry to debug, diagnose, triage, and resolve issues in real-time.

• Familiarity with performance profiling (e.g., identifying memory leaks, slow SQL queries) in high-throughput systems.

• Production Battle Scars:

• Shipped systems that process 300K+ daily transactions or handle 5k+ concurrent users.

• Experience with financial-grade uptime (99.99%+) and disaster recovery (multi region/active-active setups).

• Debugged and resolved production incidents (e.g., race conditions, deadlocks, API throttling).

• Scalability from Scratch:

• Built systems from MVP to scale (e.g., re-architected monoliths to microservices, optimized databases for low-latency queries).

• Implemented performance tuning (caching with Redis, query optimization, load and stress testing).

• Familiarity with payment rails (Pix, SEPA, SWIFT, Transferencia 3.0, etc) or blockchain (crypto wallets, send transactions). (Nice to have)

Responsibilities

• Design, build, and maintain APIs and services that integrate with banking partners, crypto wallets, and RTP systems.
• Ensure zero-downtime deployments and real-time monitoring/alerting for transaction failures.
• Lead scalability efforts (e.g., sharding databases, horizontal scaling of payment processing workers).
• Conduct rigorous load testing and chaos engineering (e.g., simulating payment failures, network partitions).
• Collaborate with security teams to enforce financial-grade auth (OAuth2, JWT, WebAuthn) and encryption.
• Architect and maintain Sentry configurations to track errors, exceptions, and performance bottlenecks across services (APIs, async workers, blockchain integrations).
• Lead post-mortems for production incidents, using Sentry data to identify root causes and implement preventive measures.
• Define and monitor key error budgets (e.g., <0.1% transaction failure rate) with actionable alerts for team response.
• Collaborate with DevOps to integrate Sentry with incident management tools (Opsgenie, PagerDuty) for real-time escalation.

What You’ll Bring

• Proven Impact:

• Portfolio of production systems you’ve scaled (share metrics: transactions/sec, error rates, p99 latency).

• Examples of architectural decisions you drove.

• Ownership Mentality:

• Experience being the “go-to” engineer during outages or critical launches.

• Built systems where a 1-minute downtime = $10k+ losses.

• Fintech Pragmatism:

• Ability to balance speed vs. robustness (e.g., shipping fast while maintaining audit trails for compliance).

• Intuition for what matters in payments (idempotency).

• Communication:

• Translate technical trade-offs into business terms (e.g., “Using Redis Cluster adds $5k/month but reduces latency by 300ms”).

• Battle-Tested Debugging:

• Examples of resolving race conditions (e.g., duplicate payments due to concurrent API requests) using distributed locks or idempotency keys.

• Experience tuning garbage collection in Python to prevent memory leaks under sustained load.

• Proactive Optimization:

• Strategies to improve performance and avoid contention, such as: Sharding databases, Rate limiting, Batching operations