[tdrp]

Thank you for this! It seems like many apps on the growth path go through this same investigation, since we arrived at many of the same conclusions you did (down to calling our own webhooks from within onMessageReceived to retry, or figure out which kinds of devices had the most problems). We spent over a year on this before we hit what I think is our maximum achievable delivery rate of around 85% (short of repeatedly hassling users to go deep into their settings or forcing them to give us an e-mail/phone number to use as backup).

Our app isn't even enabled in China but the points you make in 1 and 2 mean that plenty of devices in South America, Africa, Asia (and even some in North America and Europe) run into these problems.

I think (5) above is a serious unfairness problem since many conversations turn to "I didn't get your notification, let's talk on Whatsapp instead" which affects retention. Now 10-15% failed notification deliveries might not seem like much but if you're talking to 4-5 people either individually or in a group chat then one of them is bound to pull you into a more "reliable" app.

Incidentally we've considered actually reaching out to those top phone providers and ask to be put on the whitelist; not sure if you or anybody on here has tried anything similar.

[gdeglin]

We've tried contacting OEMs about some of the more buggy behaviors we've seen related to their power optimization features. Unsurprisingly, even when we did get ahold of someone in the US who was senior enough to understand the problem, they had limited ability to influence the China-based operations of the company. Getting whitelisted seems nearly impossible unless you are a large company with a major presence in China and connections to the OEMs.

Google has hinted that they are working on something to improve the situation, but it's been years without resolution and the problem appears to have become worse instead of better.

There's a lengthy thread in this old Android bug report about the issue https://issuetracker.google.com/issues/122098785

[tdrp]

Thanks for the link. I noticed some of these OEMs had started implementing their own "more reliable" PushKits, but I am guessing that the privacy implications are quite bad so it's basically a non-starter.

[gdeglin]

Yes. Also, for example, Huawei is not permitted to use Google Services on their new devices. As a result, they leverage a replacement called HMS and they replaced FCM with the HMS "Push Kit".

Privacy or not, it's the only way to send notifications to new Huawei devices that don't have FCM like the Huawei P40 that are sold worldwide. This isn't a niche issue -- Huawei was recently the #1 manufacturer of smartphones outside of China, surpassing both Apple and Samsung. Although this ranking has fallen as consumers have become aware of the lack of Google Services on these devices.