---
title: "Your Bolt app works in preview but the published link is blank"
description: "Preview works, published link is white. Here's why that happens with Bolt apps and the order to fix it in."
url: https://www.fomio.ai/blog/your-bolt-app-works-in-preview-but-the-published-link-is-blank
published: 2026-08-23T18:00:00.399+00:00
updated: 2026-08-23T18:00:00.399+00:00
topic: breakage-by-platform
words: 1892
---

# Your Bolt app works in preview but the published link is blank

The preview and the live site are two different copies of your app, and the live one is usually missing the settings it needs to start.

**In short:**

- The preview inside Bolt and your published site are two separate copies, rebuilt by different machines.
- The usual cause of a blank live page is that your secret keys never travelled to the host.
- Adding those keys does nothing until you publish again — they get baked in at build time.
- A "page not found" is a different problem from a white screen, and usually means the wrong folder went up.
- Nothing tells you when the live site breaks unless you set something up to watch it.

### Why does my Bolt app work in preview but not on the published URL?

Because they are two different copies. The preview runs in a temporary sandbox in your browser tab with all your keys and test data at hand. The published site is rebuilt somewhere else from scratch, and if the settings your app needs were not re-added on the host, it crashes on startup and shows a white screen.

The version inside Bolt — the little window next to the chat — is a rehearsal. It runs temporarily, at a temporary address, and it disappears when the session ends. It is fine for showing a friend on a call. It is not a product anyone can use.

The published link is a completely separate copy. Your files got packed up, sent elsewhere, and rebuilt by a machine that has never seen your Bolt chat. Everything the rehearsal had lying around has to be re-supplied on the other side.

When it isn't, the rebuilt copy loads, immediately asks for something that isn't there, and gives up. No error, no message. Just white. That is by far the most common version of this, so start there.

## Did my secret keys get copied over?

Probably not, and that is the first thing to check. Your app holds keys — the string that says where your database lives, an API key for payments, a login secret. In Bolt these sit in a Secrets panel. The technical name is *environment variables*, which just means settings kept outside the code so you don't accidentally publish your passwords.

Those settings do not automatically ride along to wherever your app gets published. A troubleshooting guide for common Bolt errors describes exactly this sequence: the settings exist in Bolt, they never reach the host, the build succeeds anyway, the app starts with nothing where the keys should be, and it dies on a generic error.

There is a sneakier second layer. For most of these apps the keys are baked into the code when it is built, not read fresh when someone visits. A long-running discussion on the Vite project — the build tool underneath most Bolt apps — is full of people expecting a setting change to take effect and finding nothing changes until the app is rebuilt. Adding the keys is not enough. You have to publish again afterwards.

1. **Open your host's settings** — Netlify, Vercel, wherever the published link actually lives. Find the environment variables section.
2. **Copy every key across** — Take each one from Bolt's Secrets panel. Same names, exactly. Capital letters matter.
3. **Publish again** — Not refresh. Publish. Until the app is rebuilt, the new settings are not in it.
4. **If you use Supabase, do it twice** — The part of your app that runs on Supabase's side has its own separate place for secrets, and Bolt then needs prompting to refresh the connection.

## Why does the live site still show my old version?

Because publishing once creates a link between Bolt and your host — it does not create a permanent live feed. The site isn't broken, it's just wrong: missing the thing you fixed yesterday.

There is a thread on Netlify's own support forum from someone who built in Bolt, published to Netlify, kept editing in Bolt, and could not work out why the live site never changed. It is a genuinely reasonable thing to be confused about.

A related trap: if you forked or duplicated your Bolt project, the copy is not connected to your existing site — forking loses the link and creates a new site instead. You may be publishing perfectly, to an address nobody is visiting. Check the address bar against the link your users have.

## Why do I get "page not found" instead of a blank page?

A real page with words on it means something different from a white screen: the files probably arrived in the wrong shape. When someone on the Netlify forum could not get a Bolt project to upload, a community moderator said the files were likely nested inside a folder, or missing the main index file at the top level.

This happens most when you download a zip from Bolt and drag it in by hand. You drag the folder containing the folder, the host looks at the top level, sees no front page, and shows a not-found. If you dragged and dropped, that is your first suspect.

One variation is worth knowing. If your home page loads fine but pasting a deeper link directly gives a not-found, that is a different problem again — and it is worth saying to Bolt in exactly those words: home page works, direct links don't.

## What if my app needs a machine that stays running?

Bolt will happily write code that expects a computer sitting there permanently, listening. Plenty of hosts do not work that way. A community deployment guide for Bolt users lists the patterns that don't survive the move: code that starts its own long-running server, or connects to a database on the same machine.

You do not need to fix this yourself. You need to be able to say it, so Bolt fixes the right thing rather than guessing.

## What should I paste into Bolt?

Something specific. Vague prompts get vague fixes and burn tokens — the person in that first Netlify thread said they had spent a million tokens trying to solve a blank live page.

**Paste this into Bolt**

```text
My published site shows a blank white page. The preview inside Bolt works perfectly. I have added all of my Secrets to my host's environment variables and published again, and it is still blank. Check whether the app crashes on startup because a required setting is missing or has the wrong name, and check whether anything in this project needs a server that stays running.
```

If the white screen survives that, open the published site, right-click, choose Inspect, and click Console. The red line at the top is the app saying what it wanted and didn't get. You don't have to understand it — paste it into Bolt word for word.

## How do I find out before a customer does?

You put something outside your app that loads the real published link on a schedule and tells you when it doesn't come back right. In every one of those forum threads, the person found out by looking. Somebody published, went to bed, and the live page was blank until they happened to open it.

That is the actual gap. Not the white screen — the silence around it. There are plenty of tools for this. Most were built for engineers, and it shows.

*Tools that watch a published link, and who each one suits*

| Tool | What it asks you to set up | What it tells you | Free option | Best for |
| --- | --- | --- | --- | --- |
| **UptimeRobot** | A link, how often to check, and which server replies count as a failure | Up or down, plus response times and history | Yes, generous | Someone comfortable with the settings |
| **Better Stack** | The same, plus rules for who gets alerted and when | Detailed reports and timelines; phone and Slack alerts | Yes, limited | Teams with an engineer |
| **Pingdom** | Checks, locations and thresholds | Deep performance data, checks from many countries | No, paid | Businesses that need real depth |
| **Uptime Kuma** | You install and run it yourself on a server you rent | Whatever you configure it to | Free, but you host it | People who enjoy this |
| **Fomio** | A link. That's the whole setup. | Working, Having trouble or Down, plus what likely went wrong in plain English | Yes — 1 app, checks every 5 minutes, email alerts, 7 days of history, no card | Someone who built the app and isn't an engineer |

Be fair about this. The engineer-facing ones are genuinely stronger in places: they check from more countries, keep longer records, and can reach you by phone, text or Slack in the middle of the night. Fomio tells you by email — not SMS, not WhatsApp, not Discord — and that is worth knowing before you pick.

What Fomio does differently is what happens after the break. It says which of three things is true, describes what likely went wrong in words you already use, and on the Builder plan it writes the prompt for you to paste straight back into Bolt. Builder also watches three apps and checks every minute; Pro adds a public status page for your users and a year of history. Current prices are on fomio.ai/pricing.

## What should I do today?

In this order: add your Secrets to your host's settings, publish again, and confirm you are testing the same link your users have. That clears most of these.

Then put something in place to watch the published link, so the next time it goes white you hear it from a machine rather than a customer. If you want that to be one link and three plain words, Fomio's free plan does it without a card.

## Questions people also ask


### Why is my Bolt preview fine but the live site blank?

The preview runs in a temporary sandbox with everything already loaded. The published site is a fresh rebuild on someone else's machine, and it only has what you gave the host. If a required setting is missing, the app crashes the moment it starts and the browser shows nothing at all. Add every key from Bolt's Secrets panel to your host's environment variables, then publish again.

### I added the environment variables and nothing changed. Why?

Because for most Bolt apps those settings are written into the code at build time, not read when a visitor arrives. Until the app is rebuilt, it still contains the old blanks. This trips up a lot of people — there is a long thread on the Vite project about exactly that expectation. Trigger a new publish and the values will be picked up.

### My home page works but direct links give a not-found. Is that the same problem?

No, it's a separate one, and it's good news because a white screen and a not-found have different causes. A not-found on the home page usually means the files went up in the wrong shape — nested inside a folder, or missing the main index file at the top level. A not-found only on deeper links is about how the host handles addresses. Tell Bolt which of the two you are seeing.

### Does Bolt keep publishing my changes automatically?

Not the way most people assume. Publishing once connects your project to a site, but every later change needs publishing again. And if you forked or duplicated the project, the copy is not attached to the original site at all — it creates a new one. That is why people edit for days and see nothing move. Always check which address you are actually updating.

### How do I know if my published app is down right now?

You won't, unless something is checking for you. Bolt does not watch the site after it leaves. The fix is a tool that loads your published link on a schedule and emails you when it stops coming back correctly. Free options exist across most of the tools in the table above, including Fomio's free plan, which watches one app, checks every five minutes and needs no card.


## Sources

[^1]: Getting Blank Page On Live Site - Working in Preview In Bolt.New — Netlify Support Forums (2024-11-25). https://answers.netlify.com/t/getting-blank-page-on-live-site-working-in-preview-in-bolt-new/130702
[^2]: Unable to upload my bolt project to netlify after trying everything — Netlify Support Forums (2025-07-16). https://answers.netlify.com/t/unable-to-upload-my-bolt-project-to-netlify-after-trying-everything/152815/2
[^3]: Updating Sites Deployed with Bolt.New — Netlify Support Forums (2024-11-05). https://answers.netlify.com/t/updating-sites-deployed-with-bolt-new/128994
[^4]: My bolt website is not working when deployed to netlify — Netlify Support Forums (2025-06-19). https://answers.netlify.com/t/my-bolt-website-is-not-working-when-deployed-to-netlify/151584
[^5]: Netlify for hosting — Bolt Support Docs. https://support.bolt.new/integrations/netlify
[^6]: Manual Deployment — Bolt Support Docs. https://support.bolt.new/docs/manual-deployment
[^7]: Netlify Deployment Guide — Bolters.io (2025-03-06). https://bolters.io/docs/netlify-deployment
[^8]: ENV variables don't work in the environments, only in build (Issue #16069) — Vite, GitHub (2024-03-01). https://github.com/vitejs/vite/issues/16069
[^9]: Bolt.new Not Working? Fix the 10 Most Common Errors — AppStuck Blog. https://www.appstuck.com/blog/bolt-new-not-working-fix-the-10-most-common-errors-2026
[^10]: How to deploy a Bolt.new app to production — livemy.app. https://livemy.app/blog/deploy-bolt-new
[^11]: Bolt app broken after deploy? Key fixes — Nightlamp. https://nightlamp.app/guides/bolt-app-broken