---
title: "Aleksander Sekowski (@aleksuix) | Hashnode"
description: "Open source engineer. Read the latest articles by Aleksander Sekowski on Hashnode."
url: "https://hashnode.com/@aleksuix"
---

@aleksuix

# Aleksander Sekowski

@aleksuix · Mountain View, USA · Joined June 2026

Open source engineer

### [The VAST Errors That Quietly Kill Video Ad Fill (and How to Catch Them)](https://awesome-adtech.hashnode.dev/the-vast-errors-that-quietly-kill-video-ad-fill-and-how-to-catch-them?utm_source=hashnode&utm_medium=feed)

Most VAST tags do not fail loudly. They under-deliver. Here are the errors that drain fill and revenue, and how to catch them before they ship.

5 min read · [awesome-adtech.hashnode.dev](https://awesome-adtech.hashnode.dev/the-vast-errors-that-quietly-kill-video-ad-fill-and-how-to-catch-them?utm_source=hashnode&utm_medium=feed)

[Jun 14](https://hashnode.com/posts/the-vast-errors-that-quietly-kill-video-ad-fill-and-how-to-catch-them/6a2e439e188d3acbc827bf50)