https://wid-blog.github.io/en/tags/project/Recent content in Project on wid's blogHugoenThu, 15 Jan 2026 00:00:00 +0000https://wid-blog.github.io/en/posts/career/dable/sensitive-data-encryption-retrospective/Thu, 15 Jan 2026 00:00:00 +0000https://wid-blog.github.io/en/posts/career/dable/sensitive-data-encryption-retrospective/A retrospective on column-level encryption of sensitive data in a running service. Envelope encryption, DEK granularity decisions, the WHERE clause constraint that led to HMAC, and the migration automation Skill that spread the work across the org.https://wid-blog.github.io/en/posts/career/dable/profitability-based-traffic-throttling/Wed, 15 Oct 2025 00:00:00 +0000https://wid-blog.github.io/en/posts/career/dable/profitability-based-traffic-throttling/Retrospective on building a system that automatically identifies low-performing SSP inventory and throttles traffic to improve contribution margin. Covers the evolution from Imp Cost Ratio to a predicted contribution margin rate approach.https://wid-blog.github.io/en/posts/career/dable/dsp-fallback-ctr-ml-lifecycle/Mon, 10 Mar 2025 00:00:00 +0000https://wid-blog.github.io/en/posts/career/dable/dsp-fallback-ctr-ml-lifecycle/Building my first ML Lifecycle — a three-tier architecture for an ad Fallback CTR prediction — as a backend engineer without an AI background. The technical decisions I made, and what I learned through running it.https://wid-blog.github.io/en/posts/career/dable/ad-fallback-server-retrospective/Wed, 28 Feb 2024 00:00:00 +0000https://wid-blog.github.io/en/posts/career/dable/ad-fallback-server-retrospective/Designing a Nest.js-based fallback server while removing a legacy ad server. Why a horizontal layered architecture fit better than Nest.js’s default vertical module slicing for a single API with complex business logic.https://wid-blog.github.io/en/posts/career/dable/ad-campaign-cache-optimization/Mon, 15 Jan 2024 00:00:00 +0000https://wid-blog.github.io/en/posts/career/dable/ad-campaign-cache-optimization/How I reduced network costs and enabled instance downscaling by switching from full cache refresh to incremental refresh for campaign configuration data.https://wid-blog.github.io/en/posts/career/dable/balanced-pacing-control/Mon, 21 Aug 2023 00:00:00 +0000https://wid-blog.github.io/en/posts/career/dable/balanced-pacing-control/A retrospective on moving ad budget pacing from a fixed-rule scheme to a two-layer control loop — per-campaign learning sets the baseline, real-time correction absorbs drift.