Publishing an Outlook add-in to AppSource: what actually happens

Every AppSource submission guide starts the same way: prepare your manifest, fill in Partner Center, click submit. What they don't tell you is what happens next — and next is where most first submissions die.

We submit Outlook add-ins to AppSource regularly, for ourselves and for clients. This is the process as it actually runs, including the parts the documentation glosses over.

Automated manifest checks are the easy part; you'll clear those in minutes. The real gate is a human tester walking your add-in against the certification policies — on a tenant that isn't yours, with test accounts you provided, following instructions you wrote. Vague test instructions are the single most common cause of a first rejection: if the tester can't reach a feature in two clicks from your notes, it 'doesn't work'.

Write your test instructions like onboarding documentation for a hostile user. Include a dedicated test account, pre-loaded data, and the exact happy path. It feels like overkill; it halves your review cycles.

Three rejections account for most of the pain we see. First: functionality that requires a paid external account without a clearly documented free trial path — policy 10.8.3 in practice. Second: any UI that renders badly in Outlook on the web even if your target market is desktop; testers check all hosts your manifest declares. Third: privacy-policy and support URLs that are technically present but generic — reviewers increasingly click them.

None of these are hard to fix. All of them cost you a full review cycle — typically three to five business days each — which is how a 'one-week submission' becomes a month.

We run an internal certification pass before every submission: the policy checklist, all declared hosts, cold-start on a clean tenant, and the test-instructions walkthrough performed by someone who didn't build the add-in. Since adopting it, first-pass approvals are the norm rather than the exception.

If you're planning an AppSource submission and want it to go through on the first pass — or you've collected a rejection you don't understand — this is exactly the kind of thing we handle inside our Outlook add-in development work.