📰 Dev.to · Nico Reyes

CSS selectors broke my scraper overnight. Here's how I made it more resilient to website changes.

Timezone confusion with Python datetime caused production scheduler to run 5 hours off. Here's what fixed it.

Automated monthly Slack message archiving to avoid hitting the 10K message limit on free tier.

Built perfect data validation. Then 400 products showed $0.00 because zero is technically a valid number.

Offset pagination broke halfway through my API integration. Cursor based pagination fixed it.

Git merged two feature branches without conflicts. My authentication code disappeared. Here's why it happened and how to avoid it.

Deployed a scraper to production and got instant 403 errors. Turns out User-Agent matters more than I thought.

Compared 3 retry patterns in Python. One is way simpler than the rest.

Automated email replies to cold outreach. Works surprisingly well with pattern matching.

Spent way too long debugging CSV import errors. Turns out Excel added invisible BOM characters that broke everything.

Third party API returned HTTP 200 for errors. Took 2 hours to figure out why my app kept crashing.

Spent 3 days debugging with console.log because my VS Code breakpoints wouldn't work. The fix was embarrassingly simple.

Unit tests passed. Production crashed. Unicode characters in price data broke my regex.

Spent days fighting rate limits. The fix was simpler than I thought.

Built a Python script to automate CSV cleanup - saves 2 hours every Monday by handling duplicates, price formatting, and date standardization

Lost 4 hours of work trying to clean up Git commits. Here's the backup branch trick that wouldve saved me.

Three endpoints, three different pagination bugs. Here's how I dealt with inconsistent API pagination.

Unit tests passed but production broke because my test data was too clean

Spent 3 days fighting rate limits while scraping product data. Here's what finally worked (spoiler: it's not just delays).

Scraped product prices from 3 sites. Got '$19.99extra', 'FREE', and other nonsense. Here's how I fixed it.

API returned 'success' with empty data. Took an hour to find out production uses pagination but test doesn't.

A debug print statement broke my production API. Took 3 hours to find it. Here's how I prevent it now.

Stopped wasting 4 hours every Monday manually checking competitor prices. Built a Python script that does it in 47 seconds.

Green tests don't mean working code. Learned this the hard way when production users found edge cases my test suite missed.