Email a test build to testers without attaching the file

The quickest way to get a test build to someone looks like email: attach the file, type "here is the new build", press send. It almost never works. The mail bounces because the file is too big, the attachment is stripped by a filter, or it arrives and the tester's iPhone has no idea what to do with it. This article explains why attachments fail, what to send instead, and what a good test build email says.

Why attaching an .ipa or .apk fails

Size

Most mail services cap attachments at roughly 20 to 25 MB per message, and the receiving side may have a lower limit than yours. A small native app can fit; anything with a cross platform runtime, a game engine or real assets will not. Some mail services swap a large attachment for a cloud storage link, which brings you back to sharing a link anyway, just a worse one.

Filters

App packages look like executable files to mail filters, and many services block them. Gmail, for example, does not allow .apk attachments. Company mail gateways often strip unknown archives too, and an .ipa is a zip archive with a different name. Your tester sees an empty message or nothing at all.

iOS cannot install from mail

Even if an .ipa arrives, an iPhone cannot install it from the Mail app. iOS installs test builds over the air only from a web page that points to a signed manifest, opened in Safari, and only if the build is signed for that device (Ad Hoc with the UDID in the profile, Development or Enterprise). An attachment skips all of that. On Android, an attached APK can install, but the tester has to download it, find it and allow installs from that app, and they cannot tell an old attachment from the newest one.

No control after you press send

An attachment cannot be updated, expired or protected. If you send the wrong build, it stays in every inbox. If it is forwarded, it travels with no password.

Send a link instead

An install link fixes each of these. The file stays on the service, the email carries a few hundred bytes, the tester taps once on the phone, and you can still set a password or stop the link later. iPhones get the proper over the air install, and Android phones get a direct download with a page that explains the unknown sources step.

Two kinds of link are worth knowing:

• A build link points to one exact build. Good for a client review of a specific version.
• A channel link always opens the newest build put into a channel such as Beta. Good for a test round with new builds every day: send it once, and testers bookmark it. On AppForShare, channels are on Pro and Team (see beta and live channels).

What the email should say

Testers read build emails on a phone between other things. Keep it short and make the next action obvious.

1. Subject with app, version and build number. "Acme 2.3 (412) ready to test" beats "new build".
2. One line on what changed and what you want tested. Release notes on the install page can carry the detail.
3. The link, opened on the phone. Say plainly: "Open this on your iPhone in Safari" or "Open this on your Android phone".
4. The password, if there is one, in a separate message or channel, not in the same email.
5. What to do if it does not install. For iPhones, the most common cause is that the device is not in the build. Point new testers to a UDID finder first.
6. How to send feedback. A reply address or the feedback form on the install page.

Leave out tracking pixels and marketing footers. A test build email is a working message, and mail filters treat it better when it looks like one.

Doing it with AppForShare

On Pro and Team, AppForShare can send the install link for you. You give up to 5 addresses per build, and each address gets one plain email: who shared which app version, the release notes if there are any (up to 600 characters), an Install button and a line on why they got it. Sending the same build to the same address again is skipped rather than sent twice, and an account can email up to 50 addresses a day. The mail has no open or click tracking. See email the install link.

You can send it from wherever you work:

• The dashboard: the "Email the link" card on the build page, with a history of who got it.
• The CLI: at upload, or later for a build that is already up.

npx appforshare upload MyApp.ipa --email [email protected],[email protected] --notes "Fixes the login crash"
npx appforshare email Stw0Ae --to [email protected]

• CI: the GitHub Action takes an email input and the fastlane plugin an email: option, so the mail goes out when the build is ready. Setup is in CI uploads and the endpoint in the CI API reference.
• AI coding tools: the MCP server has an email_build_link tool that asks for confirmation first.
• Diawi style scripts: the Diawi compatible endpoint sends the email to the addresses in callback_emails.

Two limits to know. Expired or deleted links cannot be emailed. Projects that are open only to invited testers are refused too, because those people should be added as testers instead, which brings us to Team.

Team: testers emailed on every new build

On Team, testers are people on a list, not addresses typed per build. You add them to a project or a tester group once, and they get an email when a new build arrives, in their own language: the tester emails go out in English, Hindi, Urdu, Bengali, Indonesian, Spanish and Arabic, picked per tester or learned from the install page. Private projects open only for invited testers, you can see per tester whether they opened the link or have the newest build, and a reminder can go to the ones who have not. See tester groups.

From CI you can name groups or testers at upload, and they get the new build email when it is ready:

npx appforshare upload app-release.apk --groups "Client QA,Internal" --testers [email protected]

What if you are on a free plan

Emailing from AppForShare starts on Pro. On Free, you still get the link and QR code for every build: paste the link into your own email, chat or ticket, and the rest of the advice above applies. Free builds also get a password option, the install help list on the page, and the "Send feedback" card for testers.

For a fair comparison: as published on their site in November 2026, InstallOnAir lets guests and free accounts email testers at upload, with comma separated addresses and an optional message. If free emailing from the tool matters more to you than passwords, .aab support or links that stay live, that is a real point in its favor. See AppForShare vs InstallOnAir, and if you are switching, moving off InstallOnAir.

Common questions

Can I email an .ipa file to an iPhone and install it?

No. iOS installs test builds only from an install link opened in Safari, and only if the build is signed for that device.

Why did my .apk attachment disappear?

Many mail services and company gateways block app packages. Gmail does not allow .apk attachments. Send a link instead.

How many people can AppForShare email a build to?

Up to 5 addresses per send, one email per build and address, and up to 50 addresses a day per account, on Pro and Team. On Team, use tester lists for larger groups.

Are the emails tracked?

No. The install link email has no open or click tracking.