HTML BlockHTML, CSS and JavaScript on any Confluence page
HTML Block gives you a real code editor with a live preview, renders the result right on the page, and keeps it safe with safety profiles and admin guardrails. Your code is saved in the page and never leaves Atlassian.
Coming soon to the Atlassian MarketplaceRead the setup guide
An editor that respects your code
Write a status card, a styled table, a small calculator or a whole page section, and see it exactly as readers will.
Real code editing
HTML, CSS and JavaScript each get their own tab, with syntax highlighting, line numbers, bracket matching and undo history.
Live preview
The preview updates as you type and shows exactly what the published page will show, safety profile and all.
Attached HTML files
Render an .html file attached to the page, up to 10 MB, and still restyle or script it from the CSS and JS tabs.
Helpful notices
The preview tells you when JavaScript is blocked and why, and lists links to files such as style.css that cannot load inside a block.
Fits the page
Auto height grows and shrinks with your content, or set a fixed height from 40 to 4000 px.
Limits stated up front
100 KB of code per block and attached files up to 10 MB. A size counter shows where you are while you write.
Safety you can see and set
Every block has a safety profile. Nothing is removed silently: a banner lists anything the profile took out.
| Profile | What renders | JavaScript |
|---|---|---|
| Strict | Formatting markup only. No embeds, iframes or forms. | Never |
| Standard (default) | Adds iframes, embeds and forms. | Never |
| Trusted | Your code exactly as written. | Optional, with Run JavaScript |
Admin guardrails
Confluence admins can turn JavaScript off for the whole site and cap the loosest profile any block may use. Authors can go stricter, never looser.
Isolated sandbox
Every block renders in its own sandbox. Even allowed JavaScript cannot read Confluence data, cookies or anything else on the page.
Viewer permissions
Attached files are read with each viewer's own Confluence permissions, so nobody sees a file they could not already open.
Your data stays put
No page content stored by the app, no outside servers, no analytics and no AI. Runs on Atlassian.
How it works
From install to a rendered block in a few minutes. Full step-by-step instructions are in the documentation.
- Install HTML Block from the Atlassian Marketplace into Confluence Cloud (coming soon).
- Set guardrails (optional): a Confluence admin opens Confluence administration → Apps → HTML Block and chooses whether JavaScript is allowed and the loosest safety profile authors may use.
- Insert the macro: edit a page, type
/HTML Blockand press Enter. A full-screen editor opens. - Write: use the HTML, CSS and JS tabs, or switch the source to an HTML file attached to the page, and watch the live preview.
- Choose a safety profile and height: Strict, Standard or Trusted; auto or fixed height.
- Save and publish: every viewer sees the block exactly as it looked in the preview.
Pricing
Billed by Atlassian through the Marketplace. The app never asks for payment details.
Up to 10 users
Every feature, no trial needed.
11 users and up
Per user per month for 11-100 users, with volume pricing down to US$0.07 at the largest tiers.
- 30-day free trial
- Same features at every tier
Frequently asked questions
What is HTML Block?
HTML Block is an Atlassian Confluence Cloud app by Wattlebrooks Apps that adds one macro, HTML Block. You write HTML, CSS and JavaScript in a code editor with a live preview, or pick an HTML file attached to the page, and the result renders on the Confluence page inside an isolated sandbox.
Does my HTML ever leave Atlassian?
No. Your code is saved inside the Confluence page itself, like any other macro. The app sends nothing to outside servers and uses no analytics, tracking or AI. The only thing it keeps is the site's guardrail settings, held in Atlassian-hosted app storage. HTML Block is eligible for Runs on Atlassian.
How does HTML Block keep pages safe?
Three ways. Every block has a safety profile (Strict, Standard or Trusted), and the default Standard profile removes all scripts, with a banner listing anything removed. Site admins set guardrails that authors cannot loosen. And every block renders in an isolated sandbox, so even allowed JavaScript cannot read Confluence data, cookies or anything else on the page.
Why isn't my JavaScript running?
JavaScript only runs when the block's safety profile is Trusted, Run JavaScript is on, and a site admin has not turned JavaScript off for the site. Whenever your JS tab has code that will not run, the preview shows a notice saying which of these is stopping it.
Who controls what authors are allowed to do?
Confluence admins. In Confluence administration, under Apps, the HTML Block page has two guardrails: Allow JavaScript, which turns author JavaScript off for the whole site, and Maximum safety profile, which caps every block at Strict or Standard. Authors can always choose a stricter setting on a single block, never a looser one.
Can I render an HTML file attached to the page?
Yes. Switch the block's source to Attached file and choose any .html or .htm file attached to the page, up to 10 MB. The CSS and JS tabs still apply, so you can restyle or script the attached markup within the block's safety profile. Each viewer needs permission to see the attachment.
Can a block include HTML from a web address?
No, and that is deliberate. HTML Block never fetches content from outside your Atlassian site, which keeps your data inside Atlassian. Attach the file to the page instead. Markup you write yourself can still embed an image or iframe from another site under Standard or Trusted; the viewer's browser loads it like any link.
What are the limits?
100 KB of combined HTML, CSS and JavaScript per block, attached HTML files up to 10 MB, and fixed heights from 40 to 4000 px (or auto height). There is no app limit on the number of blocks per page.
How much does HTML Block cost?
HTML Block is free for up to 10 users. Above that it is priced per user per month on the Atlassian Marketplace, from US$1.23 for 11 to 100 users down to US$0.07 at the largest tiers, billed by Atlassian with a 30-day free trial. It is coming soon to the Atlassian Marketplace.
Is HTML Block a Confluence app?
Yes. It is for Confluence Cloud only. You install it into Confluence and insert it on Confluence pages and blog posts with /HTML Block.
Ready when your pages are
HTML Block is coming soon to the Atlassian Marketplace for Confluence Cloud.
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