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Flat / Stacktree alternative

Share your report and the files behind it.

Use Flat to share a PDF report and its spreadsheet at one link, or publish an HTML report from your usual editor or agent. Stacktree adds on-page feedback and client portals. Flat suits file delivery when you already collect feedback elsewhere.

Try your files Compare with Stacktree

Upload in your browser or publish with the CLI. Start free.

Send the finished work in the format you have

A report with supporting files

Upload your PDF and spreadsheet together. Flat gives visitors a file browser so they can choose a document, read a supported preview, and download the original. You do not need to turn the documents into a web page first.

For an HTML report, publish the finished page and its assets. A root index.html opens as the report instead of the file browser. Spreadsheet previews show data and saved formula results; visitors need the original workbook to edit or recalculate it.

Browse files together · Supported document previews

A page clients can comment on

Keep Stacktree if clients use its comments to point at changes, or if you need its client portals and reading analytics. A Flat file collection does not replace those tools.

On Stacktree, clients can leave feedback without an account. Each reader sees their own comments and their status; the page owner sees the collected feedback. An agent can make the edits and resolve the comments.

How Stacktree handles client feedback

Flat vs Stacktree

We checked Stacktree's official docs and pricing on . Each comparison links to its source.

Share a report

Flat
Publish finished HTML, or share a PDF and supporting documents together. Visitors can preview supported files and download the originals.
Stacktree
Publish HTML reports and pages with optional comments. Its API accepts Markdown and website ZIPs too. Source

Update a shared link

Flat
Each upload has its own version link. Point a named address or your domain to the new upload through the CLI or API for a latest-copy link.
Stacktree
Replace a page in place to keep its URL. Its MCP tools can list earlier versions and restore one at the same address. Source

Collect feedback

Flat
Readers can open and download files. Collect comments through your existing email or review tool; Flat has no built-in comment system.
Stacktree
Clients can select text or click an image to leave a comment. You or your agent can read it, revise the page, and mark the comment resolved. Comments do not work on end-to-end encrypted pages. Source

Control access

Flat
Set a visitor password or an expiry through the CLI or API. The browser uploader creates public links. Flat has no email-domain gate or burn-after-read setting.
Stacktree
Set a passcode, an expiry, or burn-after-read. An email-domain gate can require visitors to verify an address before the page opens. Source

Publish with an agent

Flat
Your agent can run the CLI to publish files or folders. Use the REST API for your own integrations.
Stacktree
Connect an agent through its hosted MCP server, or publish through its CLI or HTTP API. Agents can update pages and manage client feedback. Source

Try before signing in

Flat
Signed-out browser uploads ask for your email and expire after one hour. Sign in before that deadline to keep the upload online.
Stacktree
The first anonymous link lasts 24 hours. Claim it into an account to manage it under that account's plan limits. Source

Compare free retention and upload size

Flat's signed-in Free uploads have no default expiry. Stacktree Free has a seven-day deadline, but accepts more data per page. Check both against the report you need to send.

Flat plans

Free includes 5 MiB per upload, 1 GiB of storage, and 5 GiB of monthly transfer. Named onflat.page addresses and visitor passwords are included.

Starter is €9 a month for 100 MiB per upload, 50 GiB of storage, 100 GiB of monthly transfer, and 1 custom domain.

All Flat plans and allowances

Stacktree plans

Free allows three pages over the life of the account, at 25 MB per page. Each expires after seven days. Deleting a page does not restore a slot. Passcodes and comments are included.

Solo is US$19 a month for 25 active pages, 250 MB per page, one custom domain, and one client portal. It adds email gates and viewer counts, with no default page expiry.

Studio is US$79 a month for unlimited pages, ten custom domains, ten client portals, and engagement analytics. Firm is US$249 a month, with 1 GB per page, 25 custom domains, and unlimited client portals. Enterprise has custom annual pricing.

Stacktree also lists a US$5 one-time unlock to remove expiry from one page through its agent-payment system. Studio's in-page brand styling and Firm's team roles are marked as coming soon.

Stacktree pricing and allowances

Flat prices are in EUR; Stacktree prices are in USD. Flat uses MiB and GiB; Stacktree publishes MB and GB. Flat's upload limit covers all files in one upload. A larger upload allowance does not guarantee a document preview.

Try Flat with a report.

Choose a report or a few files to share together. Browser uploads are public. If you are signed out, enter your email and sign in within one hour to keep the upload online.

Checking your upload limits... · Public · Limits

Drop your report files here

or choose files from your device.

Select files

For a password-protected report or a website folder, use the CLI. It preserves nested file paths and lets you set access controls before publishing.

Move a copy before replacing your shared link

Start with your original files

Use the report or website files you published to Stacktree. For HTML, put index.html and its assets in a folder such as ./report. Extract a website ZIP before publishing to Flat.

With Node.js 20 or newer, publish the folder:

npx -y @getflat/cli deploy ./report

This command creates a public link. For restricted files, follow the password publishing instructions first. Open the result and check the report and its downloads. Sign in before expiry to keep a signed-out upload.

Recreate access and update settings

Stacktree's comments, reading history, and client portal settings do not move with the files. Flat does not reproduce its email-domain gates or end-to-end encryption. Check which access controls your report needs before moving it.

Each Flat upload gets a new version link. For repeat reports, use a named address and point it to each new upload through the CLI or API. You can also connect your own domain. Stacktree-hosted addresses stay with Stacktree.

Before you switch

Does Flat keep my report online after seven days?

Signed-in uploads have no default expiry. Signed-out uploads expire after one hour, so sign in before that deadline to keep them. Your plan's storage and transfer limits still apply. Check Flat's allowances before sending a report to a large audience.

Can I share a link to the exact version I sent?

Yes. Each Flat upload has its own link. Publishing a revision leaves the earlier files unchanged while that upload remains available. A named address can point to the latest upload as well. Include assets and data in your export if you need a self-contained copy; external content can still change.

Can my Stacktree agent publish to Flat?

An agent that can run shell commands or call an HTTP API can publish through Flat's CLI or REST API. Update its publishing instructions and credentials. Stacktree MCP calls such as publish_html and update_site do not work against Flat's API.

Can readers download the files?

Yes. Flat lets readers download original files, including files that cannot be previewed. A visitor password restricts access to an upload; it does not stop someone with access from saving or forwarding a copy. Generated file viewers keep Flat branding and cannot be embedded in an iframe.

See how your report opens in Flat.

Upload a report and its supporting files. Check the preview and downloads before sharing the link.

Try your report