Policy table: attachments versus hosted links
None of the four vendors' help articles that we reviewed describe sending a true file attachment with a bulk campaign. Each one uploads the file somewhere and gives the reader a link. The details differ in ways that affect plan choice. [1] [3] [5] [8]
| Platform | How files reach the reader | File types documented | Size guidance | Plan note |
|---|---|---|---|---|
| MailerLite | Hosted in the file manager, used in campaigns [3] [4] | JPEG, PNG, GIF, ICO, PDF, ePUB [3] | Images under 10 MB; no document limit stated [3] | No plan restriction stated [3] |
| Kit | File block inserts a link: "a downloadable file, not an attachment" [1] | PDFs, images, documents, videos, MP3s [1] | 10 MB recommended [1] | No plan restriction stated [1] |
| beehiiv | Free digital products for lead magnets; a "File Attachment" item appears in the legacy editor's slash menu without further documentation [5] [6] | Not specified [5] | Not specified [5] | Free products on all plans [5] |
| Moosend | File option uploads the file and adds a link [8] | PDFs, Word documents, images, other types [8] | Up to 20 MB [8] | Enterprise accounts only [8] |
Why links beat attachments for newsletters
The vendor docs give three practical reasons. First, size: Kit ties its 10 MB guidance to email client limits, so a heavy file can stop a message being accepted at all. [1]
Second, weight. beehiiv says email weight can negatively influence spam filters if an email appears too heavy, and that Gmail clips email content above 102 KB. A link adds a few bytes. A file adds its full size. [7]
Third, control. A hosted file can be replaced on your server after sending, and a link can sometimes be repointed: Kit documents editing a link's URL in a sent Broadcast on its Pro plan, from the Clicks tab. An attachment, once delivered, cannot be changed. [9]
Delivering a lead magnet automatically
This is the job most people mean when they ask about attachments. Each platform has a documented path, and none requires an attachment.
- Kit: unchecking "Send confirmation email" also disables double opt-in, so decide how the incentive will be delivered before you change it. [2]
- beehiiv: subscribers still receive a free product while their double opt-in status is pending, and each claim is recorded as an order you can segment on. [5]
- Everywhere: put the download link above the fold in the first email, and repeat it once in a follow-up for people who missed it.
| Platform | Documented delivery method | Steps |
|---|---|---|
| Kit | Incentive in the confirmation email [2] | Landing page or form Settings, Confirmation Email section, select Download, Choose a file, save. Or redirect to a URL of your choice. [2] |
| beehiiv | Free digital product [5] | Monetize, Products, New product, choose Free product, complete details. Optionally require a survey first. [5] |
| MailerLite | Hosted PDF or ePUB linked from a welcome email [3] [4] | Upload the file in the file manager, then link it in the first email of a signup automation. |
| Moosend | File link in the welcome email, on enterprise accounts [8] | Text item, File, upload up to 20 MB, then preview to confirm the link opens. [8] |
Worked example: a 6 MB PDF checklist
Hypothetical: you want to deliver a 6 MB PDF to new subscribers. On Kit, add it as the confirmation incentive. It is under the 10 MB guidance and arrives as a download link. On beehiiv, create a free digital product, which also gives you a segment of everyone who claimed it. On MailerLite, upload it to the file manager and link it from the welcome automation. On Moosend, the built-in File option needs an enterprise account, so on other plans host the PDF on your own site and link it. [1] [2] [3] [5] [8]
If the file were 25 MB, it would exceed Moosend's 20 MB upload and Kit's guidance. Compress it, split it, or host it yourself. [1] [8]
Checklist before you send a file
Use this regardless of platform.
- Host the file and link to it. Do not try to force a true attachment into a bulk send.
- Keep files under 10 MB where possible, following Kit's email-client guidance. [1]
- Name the link after what the reader gets, not the file name. Kit notes that its File block uses the file name as the default link text. [1]
- Confirm you own the rights to the file. MailerLite's terms make uploaders responsible for hosted PDFs and ePUBs. [4]
- Preview the email and click the link before sending, as Moosend recommends. [8]
- Keep the email itself light so it is not clipped. See our Gmail clipping guide for the 102 KB threshold. [7]
Questions before you decide
Can I attach a PDF to a MailerLite campaign?
MailerLite's file manager accepts PDF and ePUB files, and its terms describe hosting EPUB and PDF files for use in campaigns, websites, landing pages and pop-ups. The help articles we reviewed describe hosted files, not a MIME attachment option, so plan on linking the hosted file.
What is the largest file Kit lets me add to an email?
Kit's "Adding files to your emails" article recommends 10 MB, which it calls the maximum allowed by many email clients. Kit includes the file as a downloadable link labelled with the file name, not as an attachment.
Does Moosend support attachments on every plan?
No. Moosend's "Attach a file" article says that if you do not see the File option in the text toolbar, you do not have an enterprise account. Files can be up to 20 MB, and the editor inserts a link to the uploaded file.
How do I deliver a lead magnet automatically on beehiiv?
Create a digital product priced as free under Monetize, Products. beehiiv emails it to new subscribers with a link to the subscriber management center for re-downloads, and delivers it even if their double opt-in status is still pending.
Sources & verification
Product details and prices can change. Check the linked provider before buying.
- Kit Help: Adding files to your emails Accessed 30 Oct 2026
- Kit Help: The Confirmation Email Accessed 30 Oct 2026
- MailerLite Help: How to add and edit images using the file manager Accessed 30 Oct 2026
- MailerLite: Terms of Service Accessed 30 Oct 2026
- beehiiv Support: Using free digital products as lead magnets Accessed 30 Oct 2026
- beehiiv Support: Using the legacy post editor Accessed 30 Oct 2026
- beehiiv Support: Ways to manage email weight and avoid Gmail clipping Accessed 30 Oct 2026
- Moosend Docs: Attach a file Accessed 30 Oct 2026
- Kit Help: Change a URL after sending an email Accessed 30 Oct 2026
Sources link directly to providers. Product buttons may use separately labeled affiliate links. Read our disclosure.