Every few months a small business owner asks me the same thing: someone fills in the contact form on my website, so where does that lead actually go? For a lot of people the honest answer is "an email that gets buried by lunch." If you want your leads somewhere you can search, sort and follow up from, you have three obvious free options: Supabase, Airtable and Google Sheets. I run the backend for my own site on one of them, so this is not theory. Here is how they really compare when they sit behind a website contact form.
What does a form backend actually need to do?
Strip away the hype and a lead store has a boring job. It has to accept a write every time the form is submitted, hold that record reliably, let you read it back to follow up, and ideally let you automate a notification or a follow-up email without you babysitting it. That is the whole brief. The question is not which tool is most powerful in the abstract, it is which one does that boring job for free without tripping over a limit at the worst possible moment.
The backend also has to play nicely with the rest of your stack: notifications, follow-up sequences, maybe a small dashboard. It is the same logic that drives where you keep your visitor stats, which is why I am publishing a companion piece on Vercel Analytics vs Plausible vs Umami the same day as this one. Keep those four jobs, write, store, read, automate, in mind as we go.
Why does Supabase win for a lead store?
Supabase is a hosted Postgres database with an API on top, and for a form-backed lead store it is my pick. The free plan gives you 500 MB of database space, 1 GB of file storage, 5 GB of bandwidth and two free projects, with unlimited API requests inside those limits. That last part is the whole game. Your contact form endpoint writes a row on every submission, your dashboard reads rows when you check it, and none of that eats into a monthly call budget. You also get real SQL, so "show me every mortgage lead from June that I never replied to" is one query, not a manual scroll. And there is zero forced branding on anything.
There is one trap you have to know about, and I will not pretend it does not exist. On the free plan a project pauses after 7 days with no database activity and has to be restarted by hand from the dashboard. If your form goes a quiet week with no leads, the database can be asleep when the next one lands, and the write fails. The fix is cheap and boring: a weekly cron job that runs one throwaway query to keep the project awake, plus a try/catch around your insert so the notification email still goes out even if the write hiccups. The paid plan at 25 USD a month removes the pause entirely, but you do not need it to start. See the Supabase free tier limits and the official Supabase pricing page.
When is Airtable the right call?
Airtable earns its place for one honest reason: you get a spreadsheet-like interface, on your phone, without building anything. If the idea of a dashboard makes you tired and you just want to see your leads in a nice grid and swipe through them from the sofa, this is the least effort path. The free plan gives you 1,000 records per base, up to 5 editors, 100 automation runs per month and, the number that matters most here, only 1,000 API calls per month.
That API ceiling is the catch. Every write from your contact form spends a call, and so does every dashboard or integration that reads the data back. At small business volume you will not hit 1,000 calls soon, but it is a monthly budget with a hard edge, and the automations stop once you burn through your 100 monthly runs. So Airtable is strong as a human-friendly viewer and weak as a busy programmatic backend. Pick it if the phone-friendly UI is worth more to you than headroom. See the Airtable plans page and this breakdown of Airtable plan limits.
Why is Google Sheets where leads go to die?
I want to be fair here, because Google Sheets is genuinely fine for one thing: a pure manual log you type into by hand. As an automated backend behind a live form, it is where leads go to quietly die. Start with capacity. A Sheet caps out at 10 million cells across the whole file, so for lead data capacity is not the problem. The problem is everything around it.
The Sheets API runs on per-minute quotas: 300 read requests and 300 write requests per minute per project, and 60 of each per minute per user, per the official Google usage limits. Fine for a trickle of submissions, but the moment you build anything real on top, you are managing exponential backoff instead of managing leads. Automation is technically free through Google Apps Script triggers, which can run on a timer or fire on form submit at no extra cost, and for simple jobs that genuinely works. But you are writing and maintaining scripts in a separate editor, and the whole thing gets brittle fast.
The dealbreaker for me is access control. Sheets sharing is at the file level, full stop. There is no real way to say "this person can see these rows and not those." Share the sheet and someone sees everything in it. For a store of customer names, emails and enquiry details, that is a poor fit. Sheets is a fantastic manual log and a bad automated lead backend. Keep it for the spreadsheet it is.
What do the free plans actually give you?
| Free plan | Supabase | Airtable | Google Sheets |
|---|---|---|---|
| Capacity | 500 MB database, 1 GB files, 5 GB bandwidth, 2 projects | 1,000 records per base, 5 editors | 10 million cells per file |
| API access | Unlimited requests within the plan limits | 1,000 API calls per month | 300 reads and 300 writes per minute per project, 60 of each per user |
| Automation | Your own cron and code, no run cap | 100 automation runs per month | Apps Script triggers, free |
| Access control | Row level security in Postgres | Base level sharing | File level sharing only |
| Main catch | Pauses after 7 days idle on free | 1,000 monthly API calls per month | No per row access, brittle at scale |
So what should you actually pick?
If you are building a proper form backend and can write or commission a little code, go Supabase, with the weekly ping to dodge the 7-day pause. If you never want to touch a dashboard and just want leads in a grid on your phone, go Airtable, and mind the 1,000 monthly API calls. If you want a manual log you update by hand, Google Sheets is fine, just do not ask it to be your automation engine. This is the kind of plumbing we sort out in our services, and it pairs with the wider work of actually getting found, which is where my notes on SEO in 2025 and on ChatGPT ads come in. Whatever you pick, the tool is the easy part. The hard part is answering fast, and I would rather help you get that right than watch good leads age in any of these three.
Frequently asked questions
Can I start on a free plan and move later without losing my leads?
Yes. All three let you export your data, so nothing traps you. Supabase gives you a standard Postgres dump, Airtable exports to CSV, and Sheets is already a spreadsheet. Start free, and only move to a paid tier when a real limit actually bites, not before. Migrating at small volume is an afternoon, not a project.
What is the 7-day pause on Supabase and should it scare me off?
On the free plan a project pauses after seven days with no database activity and needs a manual restart. It is not a reason to avoid Supabase. A weekly cron job running one small query keeps it awake, and a try/catch around your insert means your notification email still sends if a write ever fails.
Is Airtable's 1,000 API calls per month enough for a contact form?
For most small businesses, yes, at least at first. A handful of leads a day plus occasional dashboard reads stays well under 1,000 calls a month. The risk is adding integrations that each spend calls quietly in the background. Watch the counter, and if you outgrow it, treat that as your signal to move.
Why not just use Google Sheets since it is free and I already know it?
You can, for a manual log you type into by hand. As an automated backend it struggles: per-minute API quotas, brittle scripts, and no per-row access control, so anyone with the link sees every lead. For a store of names and emails, that last point alone is reason enough to keep Sheets as a log.
Founder & CEO of RB Creative Digital. Nearly two decades in SEO and digital marketing for mortgage, aviation and AI-first companies, with clients in the UK, US and Romania. His work has been featured on Forbes, Entrepreneur and HuffPost.
LinkedIn · All articles by Radu
Edited and designed by Marius Stefan · Reviewed by Cristina Gabriela
Want this set up without the trial and error?
I have spent nearly two decades wiring up the boring plumbing behind websites so it actually holds under real leads. Tell me what you are running over on the contact form and I will steer you to the backend that fits your volume.
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