name: Wilfredo Rujel
location: Lima, Peru
company: SAP
role: Senior Software Engineer
interests:
- Building scalable web applications
- Competitive programming & algorithms
- Open source contributions
currently:
- Writing technical blog posts at wrujel.com/blog
- Building developer tools & side projects
leetcode-ui Personal LeetCode progress dashboard built with Astro 7 and React 19: track s... ⭐ 0 • 🍴 0 • 
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portfolio Personal developer portfolio built with Next.js 16 and React 19, localized in... ⭐ 0 • 🍴 0 •
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blog Developer blog built with Next.js 16 and Velite, serving file-based MDX artic... ⭐ 0 • 🍴 0 • 
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webpage-gpt Cinematic landing page for GPT-Bot, a fictional floating AI assistant, built ... ⭐ 0 • 🍴 0 • 
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admin-dashboard-next Real-time admin dashboard built with Next.js 16 and React 19, pairing generic... ⭐ 0 • 🍴 0 •
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django-crud-react Full-stack task manager pairing a Django REST Framework API with a React 19 a... ⭐ 2 • 🍴 0 • 
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Stop Reaching for any: Narrowing unknown in TypeScript Why unknown is the type-safe replacement for any, and the narrowing patterns tha… |
📅 Sep 9, 2026engineering⏱ 4 min read |
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Postgres Row-Level Security for Multi-Tenant Applications How to enforce tenant isolation at the database layer with Postgres RLS instead… |
📅 Sep 6, 2026security⏱ 4 min read |
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Idempotent Background Jobs: Retries, Locks, Exactly-Once Exactly-once processing does not exist in distributed systems — here is how to d… |
📅 Aug 26, 2026backend⏱ 5 min read |
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Materialized Views in Postgres: Trading Freshness for Speed How to use materialized views to speed up expensive aggregations in Postgres wit… |
📅 Aug 22, 2026backend⏱ 5 min read |
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Idempotency Keys in Practice: Making Retries Safe How to design and implement idempotency keys so retried requests never double-ch… |
📅 Aug 15, 2026backend⏱ 5 min read |
4021 problems solved | 6 languages | 72 topics | 57% avg acceptance
| Difficulty | Solved | Progress |
|---|---|---|
| 🟢 Easy | 965/965 | ████████████████████ 100.0% |
| 🟡 Medium | 2101/2103 | ████████████████████ 99.9% |
| 🔴 Hard | 955/956 | ████████████████████ 99.9% |
| Language | Problems | Share |
|---|---|---|
| 3556 | 88% | |
 Pandas | 235 | 6% |
| 103 | 3% | |
| 67 | 2% | |
| 56 | 1% |
