How One Developer Built a $9K/Month Micro-SaaS That Does One Thing

Executive overview

Leandro Zubrezki, a self-taught developer from Buenos Aires, validated and built a Google Sheets add-on in two weeks that syncs Notion databases to Sheets. Four years later it generates $9K MRR with 70K users, 450 paying customers, and a 90% margin. The core lesson: pick a narrow integration gap, validate demand on Reddit before building, and charge from day one. Doing one thing exceptionally well inside an existing marketplace beats building a broad product from scratch.

The idea and validation process

• Spotted the gap when Notion released its official API — users wanted to export data to Sheets but no clean tool existed.
• Searched Notion's subreddit for keywords (Sheets, CSV, Excel) and found repeated demand before writing a line of code.
• Built the MVP in two weeks using Google Apps Script — no AI, just Stack Overflow and Google.
• Framework for finding future ideas: browse Zapier's most common Zaps, identify messy multi-step automations, then build a single product that replaces them.

Launch strategy

• Published to the Google Workspace Marketplace first — organic discovery from search intent is built in.
• Seeded early users by posting in Notion-related Reddit communities and Facebook groups, plus direct DMs.
• Added a live chat widget on the landing page to capture real-time feedback from new visitors.
• Product Hunt launch (18 months in) drove visibility and backlinks, not paying customers.
• Hacker News front page produced a traffic spike but similarly low conversion to paying users.

Growth and distribution

• SEO became the primary traffic channel — blog posts targeting Notion + Google Sheets search queries.
• Uses F5Bot (free) to monitor Reddit keywords (CSV, Sheets, Notion); replies to relevant threads as the founder.
• Marketplace organic search remains the top install source — being present where users already look is the compounding advantage.

Pricing and monetisation decisions

• Originally had a free plan; a large portion of users never upgraded.
• Removed the free plan — caused short-term backlash but MRR jumped from $5K to $8K within two months.
• Uses Paddle as the payment processor (Stripe unavailable in Argentina); Paddle handles billing natively.
• 90% gross margin; main cost is Google Cloud compute for real-time sync operations.

Tech stack

• Language: TypeScript; editor: VS Code (recently started using Cursor).
• Add-on runtime: Google Apps Script (extends Google Workspace natively).
• Infrastructure: Google Cloud and Firebase.
• Email: SendGrid; analytics: Mixpanel (user-level event tracking); support chat: Tidio; payments: Paddle.

Validation principles for new ideas

• Check whether competitors exist and whether they serve enterprise, SMB, or individuals — use their pricing to size the opportunity.
• Identify a clear differentiator before committing to build; without one, market entry is very hard.
• Find five users willing to try the product while you build — real usage during development is the strongest validation signal.
• Charge from day one: free usage that evaporates when pricing is introduced means the product never had enough value.

Lessons from four years of operation

• Small UI changes (moving a button, rewording a CTA) can have outsized revenue impact — test relentlessly.
• Work in spikes: batch development tasks, execute intensely, then recover; avoid low-leverage work.
• A business making $9K/month on near-autopilot is a legitimate outcome — it does not need to be a unicorn to be worth building.