What Happened When We Launched a Legal Tech Tool on Hacker News
The Launch That Changed Everything
On October 20, 2025, we submitted RentLateFee.com to Hacker News as a "Show HN" post. We expected some traffic, maybe a few comments, hopefully some constructive feedback.
What we got was a masterclass in why community-driven development matters, especially in legal tech.
The First 24 Hours
Within hours of posting, something unexpected happened: developers started stress-testing our calculator with edge cases we hadn't considered.
The comments started coming in:
"Your Utah calculation looks wrong. The law says greater of 10% OR $75, but you're returning the lesser."
Our stomachs dropped. A quick check confirmed: we had the comparison operator backwards. For rents between $75 and $750, we were returning $75 when we should have returned 10% of rent. It was a one-word bug ("Math.min" instead of "Math.max") but it would have given landlords incorrect maximum fees.
The Bug That Would Have Cost Landlords Money
The Utah bug was particularly insidious because it only affected a specific rent range. For rents under $75, both formulas returned the same result. For rents over $750, the percentage was clearly higher than $75. It was only in that middle band where the bug manifested.
Standard QA testing with round numbers ($1,000, $1,500, $2,000) wouldn't catch it. It took a developer who actually read the statute and tried rent amounts in the $400-$700 range to spot the problem.
We fixed it within 45 minutes of the first report. The HN community had done in an hour what might have taken us weeks to discover through normal user feedback.
Feature Requests That Shaped the Product
Beyond bug reports, the comments included feature requests that fundamentally shaped our roadmap:
"What about prorated rent?"
Multiple commenters asked how late fees work when tenants move in or out mid-month. We hadn't considered this edge case at all. Now our prorated rent calculator accounts for 40% of total usage.
"Can you show the actual statute text?"
Developers and landlords alike wanted to verify our calculations against primary sources. We added direct citation links and statute excerpts to every state page. Trust through transparency.
"This needs dark mode."
A seemingly trivial request, but developers are often night owls. Adding dark mode increased average session duration by 23%.
The Skeptics Taught Us the Most
Not everyone was supportive. Some commenters questioned the value proposition:
"Why would anyone use this instead of just Googling their state's law?"
This was the most valuable criticism we received. It forced us to articulate our value proposition more clearly: legal information is fragmented, outdated, and often requires calculating formulas that aren't obvious from reading the statute text.
Someone searching "Texas late fee" gets a dozen conflicting answers. They might find the statute but not understand that "10% or 12%" depends on building size. They might see the percentage but not know if there's a grace period.
Our response: we added more comprehensive state guides, included the full legal context around each calculation, and made sure every answer linked to its primary source.
Traffic and Engagement Metrics
The HN launch produced surprising metrics:
- 1,200+ visitors in first 24 hours (vs. ~50/day before launch)
- 4 critical bugs reported (all fixed within 24 hours)
- 12 feature requests (7 implemented within 30 days)
- 3 partnership inquiries from property management companies
- Sustained traffic bump of ~300% over baseline for 2 weeks
More importantly, the SEO benefits were substantial. Links from HN and subsequent blog coverage improved our domain authority and helped us rank for competitive keywords.
Lessons for Technical Founders
1. Launch Earlier Than You're Comfortable
We almost delayed the HN launch by another month to "polish" the product. We would have shipped the Utah bug to production, potentially affecting real landlords making real legal decisions. Early feedback is worth the discomfort.
2. Developer Communities Find Different Bugs
Normal users rarely read your statute citations. Developers do. They'll verify your math, question your assumptions, and catch edge cases that slip through standard testing.
3. Criticism is a Gift
The "why does this need to exist" comments forced us to clarify our value proposition. Every skeptic helps you identify weak points in your positioning.
4. Community Contributions Compound
Several HN commenters became regular users who continued to report bugs and suggest features. Building in public creates invested stakeholders.
5. Respond Quickly and Publicly
We responded to every comment, fixed bugs in real-time, and posted updates when we implemented suggestions. This built trust and encouraged more feedback.
Would We Do It Again?
Absolutely. The HN launch was uncomfortable. Watching strangers poke holes in something you've built is never fun. But the product that emerged was dramatically better than what we would have shipped otherwise.
For other founders in legal tech or any domain requiring accuracy: put your work in front of technical users early. They'll break it in ways that help you build something that won't break for real users.
Try It Yourself
The calculator that emerged from this community-driven development process is available at RentLateFee.com. Every calculation includes the citations and transparency that the HN community helped us prioritize.