30 napot töltöttem "Vibe kódolással" egy MVP-vel - 127, mindent elrontott, és még mindig megtalálta a termékpiacot

Nemrégiben belevetettem magam a vibe kódolás világába, és úgy gondoltam, hogy a tapasztalataimat mások javára katalogizálom. kódolási készségeim 25 évesek (a 2000-es évek elejétől). Annak ellenére, hogy 2018-ban megtanultam a „modern” kódolást a startupom számára, nem tekintek magam semmi másnak, mint egy kezdőnek. Tehát, amikor az AI-alapú kódolás jelensége megjelent, meg kellett próbálnom! TL;DR 30 napot töltöttem egy pénzügyi tervezési eszköz létrehozásával az alapítók számára „vibe kódolással”. Minden lehetséges hibát elkövetett. . Got calculations wrong by . Watched . $127 in Replit credits 20% 23 "interested" founders become 2 signups But I also learned that: (1) AI struggles with precision calculations, (2) founders don't want another spreadsheet—they want advice, and (3) sometimes less is more. One founder offered for the simplified version. That's validation enough to keep going. $50/month This was a great learning experience for me as I go to be on the other side of the table so to say. I spend time working with founders at accelerators and advising them about getting from zero to 1. This was a good opportunity for me to “eat my own dog food”! Here's the full story and what I'd do differently. Building a Financial Planning Tool for Founders: 3 … Table of Contents The Problem That Obsessed Me Week 1: The Honeymoon Phase (Days 1-7) Day 1: The Dream Begins Days 2-7: Early Mistakes The Magic Incantation Week 2: Reality Check (Days 8-14) Day 8-14: Travel and Trouble Day 15: Existential Dread Day 16: The Credit Crisis The Stack Choices Week 3: User Feedback Changes Everything (Days 15- … Day 17: Time for Feedback Day 18: The Humbling Day 20: Six Hours of Hell Critical Lesson Learned Day 21: The Lightbulb Moment Week 4: The Pivot (Days 22-30) Day 22: Language Regrets Day 23: The "Intuitive" Disaster Day 24: The Harsh Reality of User Acquisition Day 25: The API Awakening Day 26: Precision in Prompts Day 27: Rollback Appreciation Day Day 28: The Hard Truth Day 29: The Best Feedback Day 30: One Founder Who'd Pay The 30-Day Scorecard (Being Brutally Honest) Month 1 Statistics What I Learned About Vibe Coding The Good ✅ The Challenges ⚠️ Key Principles I Discovered 1. Be Surgically Precise with Instructions 2. One Change at a Time 3. Validate Everything 4. Use Rollback Liberally 5. Listen to Users 6. Know When to Pivot If I Started Over Tomorrow What I'd Keep ✅ What I'd Change 🔄 What I'd Skip Entirely ⛔ The One Thing I'd Do Differently What's Next? The Smart Approach: Progressive MVP Phase 1: Validate with Vibe Coding (Current - Week … Phase 2: If It Works, Go Pro (Weeks 9-24) When to Graduate Beyond Vibe Coding If You're Building with Vibe Coding: A Checklist Before You Start While Building When to Pivot Want to Help? Requirements: What You Get: Social Proof (Yes, It's Early, But It's Real) The Mission Pénzügyi tervezési eszköz létrehozása az alapítók számára: 30 napos Vibe kódolás Egy brutálisan becsületes utazás az ötlettől az MVP-ig, beleértve minden hibát, pivotot és leckét, amelyet az út során megtanultak. 8 minutes Founders building with AI, anyone considering vibe coding for serious products Reading time: Best for: The Problem That Obsessed Me "What if your churn drops by 2%?" The VC leaned forward: I watched the founder's face fall. His answer was buried somewhere in a 47-tab Excel model. It would take him 3 hours to calculate. The meeting momentum died right there. I've seen this scene play out dozens of times. Founders spending hours, sometimes days, updating financial models. Breaking formulas. Forgetting which cells to change. Creating circular references that crash Excel. The pain point I kept hearing: "I spent 2 days building a financial model for investors. Then they asked 'what if churn drops by 1%?' and I had to rebuild everything." The math is brutal: for financial planning and forecasting. Most founders hate every minute of it. A large % of startups still use spreadsheets So I decided to build something better for the founders I mentor at accelerators like Founder Institute, Flat6Labs, Ignite Program, NSRCEL and so on. Week 1: The Honeymoon Phase (Days 1-7) Day 1: The Dream Begins I dove into vibe coding with @Replit, convinced this would be straightforward. The AI influencers made it look easy on TikTok, right? My initial vision: AI-assisted financial cockpit ✨ Valós idejű adatszinkronizálás QuickBooks, Stripe Scenario planning built-in 🎯 Investor-ready exports in seconds 📄 2-3 weeks to MVP Estimated timeline: [Narrator voice: It was not 2-3 weeks] Days 2-7: Early Mistakes Reality check came fast. I made three critical early mistakes: Mistake #1: Assumed the AI agent operates in parallel Több utasítást adtam a Replit ügynöknek, miközben az előző utasításon dolgozott: "Make the dashboard cleaner" "Add a night mode" "Fix the calculation bug" The agent stopped, absorbed all the prompts, got confused, and created a Frankenstein version that did none of them well. 6 rollbacks, 3 hours lost, $23 in credits Cost: Mistake #2: Underestimated UI complexity Me: "Add night mode" AI: Result: White text on white background, buttons invisible, complete disaster Proceeds to make 47 changes Patiently working through font/background mismatches took longer than expected. 3 days Mistake #3: Wasn't precise with instructions "Make it more intuitive" AI changed the entire navigation structure Bad prompt: What happened: "Change the 'Calculate' button color to blue (#0066CC) and increase font size to 16px" Exactly what I wanted Better prompt: What happened: A varázslatos varázslat I discovered the key phrase for vibe coding for use with all vibe coding tools: "Don't make any changes without confirming your understanding with me." Ez az egyszerű útmutató megmenthetett volna . $50+ in wasted iterations Week 2: Reality Check (Days 8-14) 8. és 14. nap: Utazás és gondok Summer travel (to Japan), slowed me down, but also gave me perspective on what wasn't working. Things I learned while vibe coding from airport lounges: Hotel WiFi + Replit = frusztráció TypeScript errors are harder to debug on mobile The rollback button becomes your best friend I would recommend Replit as your starting point for Vibe coding if you do not know much about coding and deploying applications. Replit handles all that easily. Azt is gondoskodik az API kulcsok és titkok védelméről, ami azt jelenti, hogy nincs adatszivárgás és magas felhő vagy AI számlák! Plusz van egy dedikált AI ügynök, akivel beszélgethet, megértheti a kódot, felülvizsgálhatja a kódot, és megtervezi a munkáját, mielőtt létrehozza. 15. nap: Létező félelem Recurring error to render the screen Még mindig debütál Finally understand it's a TypeScript type issue Still broken Tuesday, 3:47 PM: Tuesday, 4:15 PM: Tuesday, 6:30 PM: Tuesday, 11:45 PM: Took a Csak a kód megértéséhez. whole day Should I have told the agent to use Python (a language I somewhat understand). Túl késő. Az AI ügynök kódolt a TypeScript-ben. Egy nyelv, amit nem igazán ismerek. Thank god for @Replit's rollback options. 16. nap: A hitelválság Replit credits run out FAST. Lesson learned: Az én kiadási mintám: Week 1: $34 in credits Week 2: $93 in credits (yikes!) Gyorsan iteráltam, változásokat végeztem, visszafordultam, megpróbáltam újra. Minden iteráció a komplexitástól függően 2-5 dollárba kerülhet. Budget $40/week maximum. If I hit the limit, stop and reflect on why I'm burning through credits. This is where the limit feature in Replit comes in handy. New rule: The Stack Choices Az integrált : for system emails (free tier = win). Basically to send emails to users. @Brevo for the built-in AI advisor (seemed cheap at first...). I assumed that Open AI API calls would be too expensive. @MistralAI Mindkettő ésszerűnek tűnt.A MistralAI választása visszatérne, hogy megbotránkoztasson. Week 3: User Feedback Changes Everything (Days 15-21) 17. nap: a visszajelzés ideje After clearing up errors while traveling, I started hunting for testers. Posted in 3 founder Slack channels: "Building a financial planning tool that doesn't suck. Need critical feedback. DM if interested." Response: 🦗 krikett Day 18: The Humbling Finally got and to try the MVP. 1 friend 2 founders The feedback was... brutal: Issue #1: Financial calculations were off by 20% Egy alapító CAC számítása azt mutatta, hogy when it should have been . $47 $58.75 That 20% error could have cost them their Series A round. I had MistralAI calculate it based on vague instructions. The AI made assumptions about what "customer acquisition cost" meant. Why it happened: Issue #2: Export feature crashed on larger models Any model with >50 rows of data caused a memory overflow. Issue #3: "Too many clicks to get to runway calculation" The thing founders wanted most (runway) was buried 3 screens deep. This was definitely harder than the AI influencers make it seem! Day 20: Six Hours of Hell LTV/CAC calculations were consistently wrong. The bug: 6 hours straight debugging Time spent: @MistralAI was interpreting "monthly churn" as "annual churn" in some scenarios, and "annual churn" as "monthly churn" in others. The cause: When I asked it to "calculate customer lifetime value," it made assumptions: Sometimes it used monthly churn rate Sometimes it used annual churn rate Néha kitalálta a saját churn számítását Legyen sebészeti szempontból pontos pénzügyi képletekkel. The fix: Bad prompt: Calculate LTV Good prompt: Calculate LTV as: (Average Revenue Per User * Gross Margin) / Monthly Churn Rate where: - Average Revenue Per User = Total MRR / Active Customers - Gross Margin = (Revenue - COGS) / Revenue - Monthly Churn Rate = Churned Customers This Month / Active Customers Start of Month Critical Lesson Learned Always validate AI outputs with manual calculations first. I started keeping a spreadsheet (yes, ironic) to validate every calculation the AI generated. Day 21: The Lightbulb Moment One founder cut through all the complexity: "I don't want another financial model builder. I just want to ask 'how do I extend runway by 3 months?' and get an answer." So simple. So obvious. I started pivoting immediately. Natural language queries → instant financial insights. This changed everything. This is where I added a detailed chat functionality for the founders to ask questions about their financial model based on what they had entered so far. Week 4: The Pivot (Days 22-30) Day 22: Language Regrets Kezdjük a TypeScript helyett a Python. Regret of the month: When financial formulas get complex, I spent more time debugging syntax than building features. Example that took 2 hours to fix: // What I wanted: const runway = currentCash / monthlyBurn; // What TypeScript gave me: Type 'number | undefined' is not assignable to type 'number' Pick programming languages you actually understand for serious projects! Note to future self: Day 23: The "Intuitive" Disaster Újra felgyújtották a hiteleket. $11 in one afternoon. I built a "scenario comparison" feature that took Mert folyton azt mondtam, hogy „légy intuitívabb”, anélkül, hogy konkrét lennék. 47 iterations "Make it more intuitive" Iteration 1: AI changes the entire layout "No, not like that, more intuitive" Iteration 2: Változik a színrendszer "JUST MAKE IT INTUITIVE" Iteration 3: AI adds tooltips everywhere ...45 iterations later... Define "intuitive" BEFORE asking for changes. New rule: A jobb megközelítés: "Intuitive means: (1) Show both scenarios side-by-side, (2) Highlight differences in yellow, (3) Add a 'Switch to This Scenario' button on the right" Day 24: The Harsh Reality of User Acquisition Posted on Kérdezzük meg a tesztelőket: 5 founder Slack groups Results: 23 „Érdekesnek látszik!” 2 tényleges aláírása 0 completed onboarding 😭 Conversion funnel: Interest: 23 Szállás: 2 (8,7%) Onboarding completion: 0 (0%) Making stuff people want ≠ Making stuff people actually use. Day 25: The API Awakening Az alapítók folyamatosan kérdezték: "Lehet szinkronizálni a QuickBooks-szal?" „Természetesen, mennyire nehéz az API integráció?” Me: [Researches QuickBooks API for 3 hours] What's required: OAuth 2.0 flow setup Webhook validation Data mapping between QuickBooks and my schema Hibaelhárítás a határértékek tekintetében Token refresh logic Accounting rules validation This isn't happening in vibe coding. Not anytime soon. Realization: Day 26: Precision in Prompts @MistralAI is great, but I learned you need for financial calculations. VERY specific prompts Bad prompt: Calculate runway Makes assumptions, might use wrong numbers What AI does: Good prompt: Calculate runway as: current_cash / monthly_burn_rate where monthly_burn_rate = (total_expenses - revenue) / months Use these exact values: - current_cash: $250,000 - total_expenses (last 3 months): $180,000 - revenue (last 3 months): $45,000 - months: 3 Show your work step by step. Gets it right every time What AI does: Precision matters in finance. No room for ambiguity. Day 27: Rollback Appreciation Day Used @Replit's rollback feature in one day. 12 times I tried to add "smart defaults" for SaaS metrics (based on industry benchmarks). What happened: Instead, I broke: The calculation engine The export functionality The scenario comparison User authentication (somehow?) Unknown, gave up after 1 hour 30 másodperc Time to fix manually: Time to rollback: Sometimes the best code is the code you don't write. Day 28: The Hard Truth After 4 weeks, I admitted what I'd been avoiding: The full vision is too complex for vibe coding. I scaled back to core MVP: ✅ Manual financial model builder ✅ AI advisor for benchmarks ✅ Basic scenario planning (3 scenarios max) ❌ Real-time integrations (later) Fejlett verzióvezérlés (később) ❌ Multi-user collaboration (later) Sometimes less is more. Day 29: The Best Feedback One founder's comment changed my entire approach: "I don't need another spreadsheet. I need someone to tell me if my numbers make sense." Tool → Advisor. This was the pivot. Not another financial model builder. An AI-powered financial advisor that: Validates assumptions Flags unrealistic numbers Suggests improvements Answers "what if" questions Néha a felhasználók pontosan megmondják, hogy mit kell építeni, ha elég figyelmesen hallgat. Day 30: One Founder Who'd Pay Posted the scaled-back version. Got brutal but helpful feedback. Then one founder said: "This is the first time I've understood my unit economics without a finance degree. I'd pay $50/month for this." That's validation enough to keep going. The 30-Day Scorecard (Being Brutally Honest) 1 hónap Statisztika Development: 30 Days coding: $127 Replit credits spent: ~3,500 (mostly by AI) Lines of code written: 73 Rollbacks executed: 1 (TypeScript) Languages learned the hard way: User Metrics: 23 Interested parties: 12 Actual signups: 3 Completed onboarding: Befejezett modellek: 3 1 Would pay: $0 Revenue: Key Wins: 🎯 Found product-market fit signal (1 founder willing to pay) Hitelesített alapvető probléma (az alapítók utálják az Excel-t) Megtalálták az egyszerűbb megoldást (tanácsadó > eszköz) Key Losses: Először is túl sok bonyolultság ❌ Didn't validate calculations carefully enough ❌ Chose wrong programming language ❌ Wasted $50+ on vague prompts Amit megtanultam a Vibe kódolásról The Good ✅ Went from idea to testable MVP in 2 weeks Rapid prototyping: $127 total vs. $20K+ for developers Low initial investment: Try, fail, rollback, try again in minutes Quick iterations: Great for boilerplate and standard patterns AI assistance: Nincs foglalkoztatási fejfájás: nincs interjú, nincs menedzsment, nincs részvény Kihívások ☀️ Hitelmenedzsment: túl sok iterációval drága lehet AI struggles with precision in financial formulas Complex calculations: Integrációs korlátok: a vállalati API-k megfelelő fejlesztésre szorulnak Stick with what you know or pay the learning tax Language constraints: Vague instructions = wasted time and credits Precision required: Debugging nehézség: Az AI által generált kód megértése nehéz Key Principles I Discovered 1. Be Surgically Precise with Instructions "Make it better" Változtassa meg a gomb színét a #0066CC-re, növelje a betűtípust a 16px-re, adjon hozzá 8px paddinget Don't say: Do say: 2. Változás egy időben Never give the AI multiple tasks in parallel. Wait for completion, review, then proceed. Bad workflow: "Add dark mode" "Fix the bug" "Improve performance" Good workflow: "Add dark mode" [Wait for completion] [Review changes] "Now fix the calculation bug in line 47" 3. Validate Everything Különösen a pénzügyi számítások. Ne bízz az AI-ban. Ellenőrizze manuálisan. 4. Use Rollback Liberally Egy oknál fogva ott van, visszafordultam in 30 days. No shame. 73 times 5. Listen to Users They'll tell you what to build. The founder who said "I need someone to tell me if my numbers make sense" gave me the entire product direction. 6. Know When to Pivot Not everything can be vibe coded. Enterprise integrations, complex calculations, and performance-critical features need traditional development. If I Started Over Tomorrow What I'd Keep ✅ Still the fastest way to test ideas Vibe coding for rapid prototyping: Critical feedback > polite feedback Brutal honesty in user testing: This is the winning insight The pivot to "advisor not tool": Accountability + audience building Daily build-in-public updates: What I'd Change 🔄 Start with Python, not TypeScript Language I understand Better for data/calculations Easier to debug Get 10 user interviews BEFORE building Would have discovered the "advisor not tool" insight on Day 1 Could have skipped 2 weeks of wrong direction. Funnily enough I take a class on “Customer Validation” at an accelerator. But did not follow my own advice! Set a 2-week deadline for MVP v1 Prevents feature creep Forces prioritization Builds shipping muscle Budget $200 for Replit, hard stop If I exceed budget, something's wrong Forces better prompt engineering Prevents death by 1000 iterations Build manual process first, automate second Would have discovered QuickBooks integration isn't MVP Could have launched 2 weeks earlier What I'd Skip Entirely ⛔ - Nobody asked for it, took 3 days Night mode Tökéletes felhasználói felület - Az alapítók funkciót akarnak a formánál - Validate manual flow first Integration promises - Get 10 paying users before adding more Advanced features The One Thing I'd Do Differently Talk to 50 founders BEFORE writing a single line of code. Not 5. Not 10. Fifty. Ask them: Show me your current financial model What takes the longest to update? What question do investors always ask? What would you pay for a solution? This would have saved me 2 weeks and $$ in wasted effort. What's Next? The Smart Approach: Progressive MVP I'm not building everything at once anymore. Here's the realistic path: Phase 1: Validate with Vibe Coding (Current - Weeks 5-8) Build: ✅ Manual financial model builder ✅ AI advisor for validating assumptions ✅ Alapvető forgatókönyvtervezés (3 forgatókönyv) ✅ Export to Excel/PDF ✅ Natural language Q&A Get to 10 paying customers at $50/month Goal: What I'm trying to prove: Core value proposition works Users prefer this vs. spreadsheets AI advisor adds real value Az alapvető gazdasági egység motorja elegendő Success criteria: 10 paid subscribers 40 Legalább 5 "nagyon csalódott" lenne, ha a termék elment Phase 2: If It Works, Go Pro (Weeks 9-24) After 50-100 paying founders, consider: Hiring fintech-experienced developers Building real-time integrations Adding enterprise security (SOC 2) Scaling infrastructure $50K-100K (bootstrap or small angel round) Budget: When to Graduate Beyond Vibe Coding Vibe coding is great for: ✅ Rapid prototyping ✅ Basic CRUD operations ✅ AI integration (OpenAI/Mistral API calls) ✅ Export functionality ✅ User feedback and fast iteration ✅ Landing pages and marketing sites Where you'll hit walls: ❌ Complex financial formulas (cohort retention curves, NPV calculations) ❌ Enterprise API integrations (OAuth flows, webhook handling) ❌ Background jobs for data sync ❌ Multi-tenant security architecture ❌ Performance optimization (sub-300ms queries) ❌ Real-time collaboration features When you have 10+ paying customers asking for features that vibe coding can't deliver. The graduation threshold: If You're Building with Vibe Coding: A Checklist Save yourself time and money. Use this: Before You Start [ ] Choose a language you actually understand [ ] Set a credit budget ($X per week max) [ ] Define "done" for your MVP (write it down) [ ] Találjon 3 felhasználót, akik tesztelnek, nem csak azt mondják, hogy "érdekesnek hangzik" [ ] Interview 10+ potential users first [ ] Write down the #1 problem you're solving While Building [ ] One prompt at a time, wait for completion [ ] Define vague words ("intuitive", "clean", "simple") [ ] Validate ALL calculations manually [ ] Use rollback guilt-free [ ] Track credit spend daily [ ] Screenshot working versions before major changes When to Pivot [ ] Ha ugyanaz a hiba 5 kísérlet után is fennáll [ ] If you're explaining more than building [ ] If test users can't complete core flow [ ] If enterprise features keep coming up [ ] If you've spent >$200 without paying users Want to Help? I'm looking for to: 10 founders Test the MVP for 1 week Jump on a 15-min feedback call Get free lifetime access if you help shape v1 Requirements: ✅ Pre-seed to Series A stage ✅ Currently use Excel/Sheets for financial planning ✅ Willing to be brutally honest (critical feedback only) ✅ Can commit to testing for 1 week What You Get: 🎁 Free lifetime access (worth $600/year) 🎁 Priority feature requests 🎁 Direct access to me via WhatsApp 🎁 Az Ön logója az "Built with Founders" oldalon 7/10 (3 már kitöltött) november 1, 2025 Spots available: DM engem a Twitteren . Want to test out what I built? Here is the link» How to apply: @RenjitPhilip https://runwayai.futureu.co @RenjitPhilip https://runwayai.futureu.co Social Proof (Yes, It's Early, But It's Real) "This is the first time I've understood my unit economics without a finance degree. I'd pay $50/month for this." — Mike R., SaaS Founder, Pre-seed "You answered my investor question in 30 seconds. It would have taken me 3 hours in Excel." — Sarah K., Marketplace Founder, Seed The Mission Kill the 47-tab Excel financial model. Every founder deserves: ✅ Real-time financial dashboards Az, ami megmagyarázza a számokat ✅ Scenario planning in seconds ✅ Investor-ready exports instantly The journey continues. Day 31 starts tomorrow. Kövesd a következőket: @RenjitPhilip #vibecoding #BuildInPublic @RenjitPhilip - If you found this helpful, share it with a founder friend who's drowning in Excel. They'll thank you later. Here is the link» P.S. https://runwayai.futureu.co https://runwayai.futureu.co