📰 Dev.to · Nico Reyes

Spent two days manually checking commits. Git bisect found the bug in 20 minutes.

Python multiprocessing crashed because my custom class wasn't pickleable. Here's what I learned fixing it.

How I dealt with aggressive CAPTCHA protection while scraping - the solutions I tried, what failed, and what actually worked.

My CI pipeline passed everything. Production was broken. The route was never registered. Tests mocked the service layer so they never caught it.

Built a link checker for my blog. Missed broken URLs behind redirects. Took a weekend to fix what clicking manually could've done in 2 hours.

I spent 4 hours trying to validate function arguments properly. Here's what kept going wrong.

Let my feature branch drift for 3 days. Had to resolve 47 commits worth of conflicts. Here's what I learned about syncing with main regularly.

Site switched HTML templates at page 187. Took 3 scrape attempts to get clean data.

CSV quote marks corrupted 2,000 product records silently. Here's what actually happened and how I fixed it.

Python exceptions point at one line but the problem is somewhere else entirely.

Docker said both containers were healthy. My app couldn't reach the database. Took 4 hours to find out they were on different networks.

OAuth token expired mid-sync and silently failed. Took 2 hours to figure out why the CRM to email platform sync was half-working.

Python's mutable default arguments bit me in production. Took an hour to find a one-line fix.

Site admin updated robots.txt while my scraper was running. 187 pages succeeded, then everything got blocked.

Automated my freelance expense categorization with a simple Python script. Saves 2+ hours per month.

One emoji in 10k CSV rows crashed my data pipeline. Here's what fixed it.

Container worked internally but refused external connections. The fix was changing 127.0.0.1 to 0.0.0.0.

Tests passed. Production broke. The culprit? Naive datetime objects that looked fine in tests but failed in production.

One malformed CSV row brought down my data processor. Here's what I learned about validation.

Docker container kept crashing with code 137. Turned out to be one character in my config file.

Got 401 errors for 3 hours. My API key was valid. The docs buried the one detail that mattered.

Tests passed but production broke. Here's what my perfect mocks missed.

Bearer token worked in Postman but failed in Python with 401. Turned out to be a trailing newline character.

Went from 4.2GB to 287MB by switching base images and fixing what I copied. 35 minute deploys became 2 minutes.