2 posts novos por semana

Blog da Hens

Lições reais de quem opera SaaS próprios em produção. Preços, erros, decisões arquiteturais e números que ninguém publica.

Jul 7, 2026

"Building a Node TUI agent without dying of OOM: 3 production crashes and the patterns I kept"

A terminal AI agent in Node grows to V8's ~2GB heap ceiling in hours. The 3 crashes I hit and the compaction, cleanup, and redaction pattern I ship now.

Read post →
Jun 30, 2026

Why I ripped Mockito out of a Flutter codebase and switched to Valenty (and what I got back)

Mockito's real cost isn't writing the mock — it's build_runner. I cut it from a 40k-line app and local test time dropped from 45s to 8s. Here's the math.

Read post →
Jun 26, 2026

"Duplicate webhook, double charge: the idempotency bug I caught in OverAir before production"

Stripe and Meta deliver the same webhook more than once. Without dedup, ~0.5% of customers get charged twice. How I caught it in an 11pm stress test, and the pattern I use.

Read post →
Jun 23, 2026

"Whisper vs Deepgram vs Google STT for real-world Portuguese audio: the benchmark I actually ran"

I ran 50 real Brazilian-Portuguese clips (WhatsApp voice notes + podcasts) through all three. Verdict: Deepgram for streaming, Whisper for batch, and I skip Google STT. The numbers below.

Read post →
Jun 16, 2026

"A pretty site doesn't sell — social proof above the fold and speed do"

Animated heroes don't convert. Social proof in the first viewport and an LCP under 2.5s do. The numbers, the right budget, and what I'd do today.

Read post →
Jun 9, 2026

"Automating Instagram publishing with AI: the technical pipeline from $0 to $40/month"

A 4-stage pipeline to auto-publish on Instagram with AI — caption, image, human review queue, Graph API. Three stacks from $0 to $40/month, with the real numbers.

Read post →
Jun 2, 2026

Why vibecoding doesn't work for mobile apps (and what to do with your v0 prototype)

v0 ships a website, Bolt ships code that won't compile for the stores. For a native app that survives review, vibecoding stalls. Here's where, and the fix.

Read post →
May 26, 2026

When to fire Lovable and hire a developer — 7-signal decision matrix

If 2+ of these 7 signals show up in your vibe-coded SaaS, stop iterating and hire a dev. Closed matrix with scoring and action band per tier.

Read post →
May 22, 2026

Vibe-coded WhatsApp bot — why it answers wrong in production (and the hardening checklist)

WhatsApp bots generated by Lovable, Bolt, or v0 break in 8 predictable ways once they hit production. Here's the checklist I run before any bot ships to a paying client.

Read post →
May 19, 2026

The real bill of vibecoding — what it actually costs to take a Lovable SaaS to 1,000 users

The 12-month invoice for scaling a Lovable-built SaaS from 0 to 1,000 active users: $3,000–$5,000 across infra, AI credits, and the rewrite nobody warns you about.

Read post →