Blog

# Writing

Thoughts on building Who's OOO, Symfony, and open-source development.

 [\#tech](/blog/tag/tech/) [\#comparison](/blog/tag/comparison/) [\#news](/blog/tag/news/)

 

 May 9, 2026

##  [ HR SaaS Vendor Risk: When Your Leave Management Tool Disappears ](https://whoisooo.app/blog/hr-saas-vendor-risk) 

Real stories of HR SaaS tools that shut down, got acquired, or hiked prices, and what they tell you about the cost of depending on a vendor for leave management.

 [\#news](/blog/tag/news/)

 [ Read more  — HR SaaS Vendor Risk: When Your Leave Management Tool Disappears ](https://whoisooo.app/blog/hr-saas-vendor-risk)  April 23, 2026

##  [ Adding Two-Factor Authentication to Who's OOO ](https://whoisooo.app/blog/adding-2fa-to-whosooo) 

How I added optional 2FA to Who's OOO: encrypted TOTP secrets, Argon2id backup codes, rate limiting, and no open-redirect traps.

 [\#tech](/blog/tag/tech/)

 [ Read more  — Adding Two-Factor Authentication to Who's OOO ](https://whoisooo.app/blog/adding-2fa-to-whosooo)  April 11, 2026

##  [ Google Sheets Leave Tracker: A Free Self-Hosted Alternative ](https://whoisooo.app/blog/leave-tracker-spreadsheet-alternative) 

Outgrown your Google Sheets leave tracker? Here's a free self-hosted alternative with approvals, Slack sync, and shared team calendars.

 [\#comparison](/blog/tag/comparison/)

 [ Read more  — Google Sheets Leave Tracker: A Free Self-Hosted Alternative ](https://whoisooo.app/blog/leave-tracker-spreadsheet-alternative)  April 4, 2026

##  [ Self-Hosted vs SaaS Leave Management: Open Source Tools Compared ](https://whoisooo.app/blog/self-hosted-vs-saas-leave-management) 

Comparing self-hosted leave management to SaaS? See the real cost difference, GDPR implications, and which open source absence tracker fits your team.

 [\#comparison](/blog/tag/comparison/)

 [ Read more  — Self-Hosted vs SaaS Leave Management: Open Source Tools Compared ](https://whoisooo.app/blog/self-hosted-vs-saas-leave-management)  March 31, 2026

##  [ Why I Built Who's OOO ](https://whoisooo.app/blog/why-i-built-whosooo) 

Every company I worked at tracked leave differently. Spreadsheets, calendar invites, Slack messages that got buried. At some point I got tired of it and built something.

 [\#news](/blog/tag/news/)

 [ Read more  — Why I Built Who's OOO ](https://whoisooo.app/blog/why-i-built-whosooo)