Common Issues
general
My App Works on My Computer but Not When I Share the Link
Everything looks perfect when you test your app on your own computer. But when you send the link to a friend, customer, or investor, they see errors, a blank page, or something completely broken. It's embarrassing and confusing.
This happens because your computer has a special setup that makes the app work — things like saved passwords, local files, or settings that only exist on your machine. When someone else opens the link, none of that is available, so the app falls apart.
It might also be that your app is still running only on your computer (localhost) and isn't actually published to the internet yet, even though you have a link that looks like it should work.
Error Messages You Might See
This site can't be reached
404 Not Found
Application error - check logs
Blank white page
Failed to load resource
Common Causes
- App isn't actually deployed — You're running it on your computer (localhost) and sharing a link that only works on your machine
- Missing environment variables — Secret keys and passwords are saved on your computer but weren't added to the hosting platform
- Database not connected in production — Your app talks to a local database on your computer, not one on the internet
- Mixed HTTP and HTTPS — Your live site uses HTTPS but some resources are loaded over HTTP, which browsers block
- Browser cache showing old version — You see the working version from your cache, but others get the broken deployed version
How to Fix It
- Test in a private/incognito window — Open your link in an incognito browser tab to see what others actually see
- Check your hosting platform — Make sure your app is actually deployed and the hosting shows it as "live" or "active"
- Add your secret keys to the hosting — Any passwords or API keys on your computer need to be added to your hosting platform's environment variables section
- Check the deployment logs — Look at your hosting platform for error messages during the build or deploy process
- Test on your phone — Open the link on your phone (not connected to your home WiFi) to confirm it works outside your network
Real developers can help you.
Franck Plazanet
I am a Strategic Engineering Leader with over 8 years of experience building high-availability enterprise systems and scaling high-performing technical teams. My focus is on bridging the gap between complex technology and business growth.
Core Expertise:
🚀 Leadership: Managing and coaching teams of 15+ engineers, fostering a culture of accountability and continuous improvement.
🏗️ Architecture: Enterprise Core Systems, Multi-system Integration (ERP/API/ETL), and Core Database Structure.
☁️ Cloud & Scale: AWS Expert; architected systems handling 10B+ monthly requests and managing 100k+ SKUs.
📈 Business Impact: Aligning tech strategy with P&L goals to drive $70k+ in monthly recurring revenue.
I thrive on "out-of-the-box" thinking to solve complex technical bottlenecks and am always looking for ways to use automation to improve business productivity.
Simon A.
I'm a backend developer building APIs, emulators, and interactive game systems. Professionally, I've developed Java/Spring reporting solutions, managed relational and NoSQL databases, and implemented CI/CD workflows.
Matthew Butler
Systems Development Engineer @ Amazon Web Services
Sage Fulcher
Hey I'm Sage! Im a Boston area software engineer who grew up in South Florida. Ive worked at a ton of cool places like a telehealth kidney care startup that took part in a billion dollar merger (Cricket health/Interwell health), a boutique design agency where I got to work on a ton of exciting startups including a photography education app, a collegiate Esports league and more (Philosophie), a data analytics as a service startup in Cambridge (MA) as well as at Phillips and MIT Lincoln Lab where I designed and developed novel network security visualizations and analytics. I've been writing code and furiously devoted to using computers to make people’s lives easier for about 17 years. My degree is in making computers make pretty lights and sounds. Outside of work I love hip hop, the Celtics, professional wrestling, magic the gathering, photography, drumming, and guitars (both making and playing them)
Mehdi Ben Haddou
- Founder of Chessigma (1M+ users) & many small projects
- ex Founding Engineer @Uplane (YC F25)
- ex Software Engineer @Amazon and @Booking.com
Anthony Akpan
Developer with 8 years of experience building softwares fro startups
Kingsley Omage
Fullstack software engineer passionate about AI Agents, blockchain, LLMs.
zipking
I am a technologist and product builder dedicated to creating high-impact solutions at the intersection of AI and specialized markets. Currently, I am focused on PropScan (EstateGuard), an AI-driven SaaS platform tailored for the Japanese real estate industry, and exploring the potential of Archify.
As an INFJ-T, I approach development with a "systems-thinking" mindset—balancing technical precision with a deep understanding of user needs. I particularly enjoy the challenge of architecting Vertical AI SaaS and optimizing Small Language Models (SLMs) to solve specific, real-world business problems. Whether I'm in a CTO-level leadership role or hands-on with the code, I thrive on building tools that turn complex data into actionable value.
Jared Hasson
Full time lead founding dev at a cyber security saas startup, with 10 yoe and a bachelor's in CS. Building & debugging software products is what I've spent my time on for forever
Jen Jacobsen
I’m a Full-Stack Developer with over 10 years of experience building modern web and mobile applications. I enjoy working across the full product lifecycle — turning ideas into real, well-built products that are intuitive for users and scalable for businesses.
I particularly enjoy building mobile apps, modern web platforms, and solving complex technical problems in a way that keeps systems clean, reliable, and easy to maintain.
Describe what's wrong in plain English. No technical knowledge needed.
Get HelpFrequently Asked Questions
What does 'localhost' mean?
Localhost means the app is running only on your own computer. It's like a private preview. To let others see it, you need to deploy (publish) it to a hosting service like Vercel, Netlify, or Heroku.
Why does it work in my browser but not my friend's?
Your browser might be showing a cached (saved) version, or your computer has settings and passwords that the live version doesn't have. Always test in an incognito window to see the real version.