My web service has been running for months. It serves thousands of users. It processes images, PDFs, videos, and 3D files.
My monthly hosting bill: $0.
Here's the actual breakdown of how this is possible.
The Stack
- Next.js — React framework with built-in API routes
- Vercel — Hosting and deployment
- Vercel KV — Redis-based key-value store (for blog posts)
- Client-side processing — The key to keeping costs at zero
Why Client-Side Processing Is the Real Answer
The reason most "free tier" projects eventually hit limits is that they do heavy processing on the server. Image resizing, video conversion, file format changes — these eat CPU time and bandwidth.
I moved all of that to the browser.
When a user compresses an image, the processing happens on their device. My server never sees the file. This means:
- No CPU costs
- No bandwidth costs for file transfer
- No storage costs
- Better privacy for users
Vercel Free Tier — What You Actually Get
| Resource | Free Limit |
|---|---|
| Bandwidth | 100 GB/month |
| Serverless Function Execution | 100 GB-hours/month |
| Build minutes | 6,000/month |
| Custom domains | Unlimited |
| HTTPS | Automatic |
| Preview deployments | Unlimited |
For a tool-based site where actual data processing happens client-side, 100GB/month is plenty. You're only serving HTML, CSS, JavaScript — not processing files.
The Additional Services I Use (All Free)
Vercel KV (Redis):
- Free tier: 30,000 requests/month, 256MB storage
- I use it to store blog posts
- Monthly cost: $0
Google Analytics:
- Free, always
- Replaced by Vercel Analytics for some metrics
Cloudflare (DNS only):
- Free DNS management
- Handles domain routing
The One Actual Cost
Domain: ~$15/year ($1.25/month).
That's it.
The Architecture That Makes This Work
User's browser
↓ (downloads JS/CSS/HTML once)
Vercel CDN (static files)
↓ (rare: API calls for blog content)
Vercel Serverless Functions
↓
Vercel KV (Redis)
File processing: entirely in browser
No file ever touches the server
What Serverless Functions Handle
Almost nothing file-related. My serverless functions only handle:
- Blog post CRUD (reads/writes to Vercel KV)
- Admin authentication (cookie-based)
That's it. For a site doing image compression, PDF editing, video conversion — zero server load from actual tool usage.
When You'll Hit Limits
The free tier will stop working for you when:
Bandwidth: You start serving large files from your server. If you're downloading 50MB files from your CDN frequently, 100GB goes fast.
Function execution: You add heavy server-side processing. Even moderate image processing at scale will exhaust 100 GB-hours/month quickly.
KV storage: You store a lot of data. 256MB is enough for text content but not file storage.
When to Upgrade
I'd upgrade when:
- Monthly active users exceed ~10,000 with server-side processing
- I add features that require server computation
- Revenue justifies the $20/month Pro plan
The Honest Limitations
Commercial use restrictions: Vercel's free tier has commercial use restrictions. If you're generating revenue, check their terms carefully.
No persistent connections: Serverless functions can't maintain WebSocket connections or long-running processes.
Cold starts: Serverless functions sleep when not in use. First request after idle period has latency.
Region limits: Free tier has limited region options for function execution.
What I'd Do Differently
One thing I'd do from day one: set up spending alerts on any pay-as-you-go services. Even if you're on free tiers, some services (like certain databases) will charge for overages without warning.
The Broader Point
The combination of:
- Client-side processing (no server load from tools)
- Vercel free tier (generous for static + serverless)
- Free-tier databases (Vercel KV, Neon, Supabase)
...means you can build and run a serious web service for essentially free, at least until you hit meaningful scale.
For side projects and early-stage products, this removes a significant barrier. You don't need to worry about server costs until you have users — and by then, you can afford to pay.
This is the architecture behind ToolZip — 52 browser-based file tools running on Vercel's free tier.
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