Launch HN: Emerge (YC W21) – Monitor and reduce iOS app size
45 comments
Definitely cool from a tech standpoint, but what is the value proposition here? I get that smaller = better, but why should I invest my engineers time in optimizing size using the results you output vs delivering new features or bug fixes to customers?
There are limits based on the size of the binary that apple will allow on the app store. In addition, here's a really interesting story about how uber had to fight to downsize the app cause they realized that staying under the cellular data limit made people able to download the app when they were on the go: https://twitter.com/StanTwinB/status/1336890442768547845
I used to run an iOS testing-as-a-service thing. Few of our customers came close to the App Store limits. The ones that did were games and they are definitely not looking to optimize apps for the long term. We did have some unicorn customers but they weren't doing 2GB downloads, for the reasons you mention.
So how many customers could this startup conceivably get? Unless you're a game with lots and lots of graphical assets, you have to be the kind of company with more ability to employ developers than to coordinate them (i.e. a unicorn).
It's also a moving target as limits are continually revised upwards. I assume they have done some diligence about their TAM, but I don't get understand the plan just yet.
So how many customers could this startup conceivably get? Unless you're a game with lots and lots of graphical assets, you have to be the kind of company with more ability to employ developers than to coordinate them (i.e. a unicorn).
It's also a moving target as limits are continually revised upwards. I assume they have done some diligence about their TAM, but I don't get understand the plan just yet.
The real point I got from this is not to use brand new and not battle tested technology in production.
Sure, everyone loves a rewrite, but perhaps Swift wasn't ready for it.
Sure, everyone loves a rewrite, but perhaps Swift wasn't ready for it.
People with small capacity phones (a lot of people) won't install your app, and may actually uninstall it if it's too big. That may not be priority #1, but it certainly deserves some consideration.
Exactly! Emerge aims to make it as easy as possible to fix app size issues, so you can prioritize it similar to other bug fixes. With our pull request comments alerting you to size increases right when they happen you can easily see why size increased and remedy it all before the change makes it to users.
I mean, Facebook is a quarter of a gigabyte for God knows what reason. Many apps are similar. There’s a reason the base capacity is 64 GB: apps keep getting bigger.
However, the cellular size limit is now 250 MB IIRC, so Facebook seems to stay just under that.
However, the cellular size limit is now 250 MB IIRC, so Facebook seems to stay just under that.
The base capacity is 64 GB now, but lots of phones of 32 GB and even 16 are still usable (the original iPhone SE, for instance, was sold in a 16 GB version and runs the latest iOS).
These older phones are way more common outside of the US and even just outside of the SFBA where not everyone buys a new $1000+ phone every 2 years.
These older phones are way more common outside of the US and even just outside of the SFBA where not everyone buys a new $1000+ phone every 2 years.
It's 200mb now before a prompt shows warning users of the size they are about to download.
Indeed! Our app (a shift management app) at work is ~20mb, and I felt like that was quite a big commitment to expect people to have on their phones!
As a user, I appreciate smaller app size as I equate it with better developer skills and, it downloads faster. (I had even made a feedback request to Apple that they show the size of apps in App Store Updates as "it helps me estimate how much time an app update may take. - glad they did so).
Performance is the currency which you trade for ease of development, new features, etc.
Ignoring performance comes at a cost to you (server side resources) and your users (device resources). This is why generation after generation devices get more powerful and slower (from user point of view).
It is up to you to find out which point in the performance vs new feature/bugfix tradeoff gives you maximum value.
Ignoring performance comes at a cost to you (server side resources) and your users (device resources). This is why generation after generation devices get more powerful and slower (from user point of view).
It is up to you to find out which point in the performance vs new feature/bugfix tradeoff gives you maximum value.
Not sure whether they will tackle Android as well, but I know there are strict limits on APK size to be eligible for Play Store features like Instant Apps.
Android support is definitely on our roadmap!
What do you say to people who argue that users have more than enough space for large binaries, and if they don't they are not ideal customers (because otherwise they would have the money and desire to upgrade to the bigger size)?
Good question! Many apps are trying to expand around the world and have a global presence. This is actually what originally inspired the idea for Emerge. App size is crucial if you are trying to break into new markets where users might not have the latest iPhone or be on 5G. Generally, we don't think companies want to exclude users because of a technical issue, and engineers are motivated to build the most performant apps they can. A healthy app size is also a good indicator of a high quality app since it affects other metrics such as download and app launch time.
Awesome, that makes a lot of sense thank you
$499/month! That seems expensive - is it a big problem when Apple does a lot with App thinning? Big enough of a problem for $499/month?
This is not intended to be a justification for why I don't want to pay for this service, it's intended as honest feedback about the shock I had seeing the price, and why I think it might be, in the hope that it helps the team iterate their offering.
This price feels wrong, and I think part of it is the pricing of the other similar sorts of service we use for our app, and that I suspect others use.
Ultimately this service and the others are about improving reliability and quality in some sense, so while different markets I think they are comparable as teams can opt to focus on quality in different areas.
- CI, we pay $100-200 for this, and it obviously consumes a lot of compute resources and needs to regularly. Price feels ~reasonable.
- Crash reporting, we pay <$100 for this. It scales with user base, and while low cost per user this does feel like it has some scale to it. It's also essentially user-facing, so very high uptime requirements.
- Code coverage, $5. It's basically a few database records behind an API with a special interface. Feels like it's worth very little, but fantastic price, worth it. Also coverage is similar metric to app size – a small change is probably ok, but long term trends are an issue, so in a way it provides a similar type of value.
- And then we come to this. $500. The analysis is a complex bit of code I'm sure, and the company should be able to charge for that, but there isn't compute, (significant) storage, or high SLAs as a necessary part of the product. It feels "wrong" next to these other services.
I think all of these feelings roughly boil down to intuition around the cost of goods sold (COGS). Logic that has already been written has a low COGS, and while that doesn't mean it should be free at all, it does make it hard to justify over being, say, a standalone piece of software that one buys once. Perhaps a way to circumvent this is to go hard on the constant evolution of the platform as Apple changes their technologies.
Maybe this is all from the viewpoint of someone who would likely be on the free plan! And so maybe this is a non-issue, but we'd happily pay for this, it just feels like it's a $50/mo service not a $500/mo one.
This price feels wrong, and I think part of it is the pricing of the other similar sorts of service we use for our app, and that I suspect others use.
Ultimately this service and the others are about improving reliability and quality in some sense, so while different markets I think they are comparable as teams can opt to focus on quality in different areas.
- CI, we pay $100-200 for this, and it obviously consumes a lot of compute resources and needs to regularly. Price feels ~reasonable.
- Crash reporting, we pay <$100 for this. It scales with user base, and while low cost per user this does feel like it has some scale to it. It's also essentially user-facing, so very high uptime requirements.
- Code coverage, $5. It's basically a few database records behind an API with a special interface. Feels like it's worth very little, but fantastic price, worth it. Also coverage is similar metric to app size – a small change is probably ok, but long term trends are an issue, so in a way it provides a similar type of value.
- And then we come to this. $500. The analysis is a complex bit of code I'm sure, and the company should be able to charge for that, but there isn't compute, (significant) storage, or high SLAs as a necessary part of the product. It feels "wrong" next to these other services.
I think all of these feelings roughly boil down to intuition around the cost of goods sold (COGS). Logic that has already been written has a low COGS, and while that doesn't mean it should be free at all, it does make it hard to justify over being, say, a standalone piece of software that one buys once. Perhaps a way to circumvent this is to go hard on the constant evolution of the platform as Apple changes their technologies.
Maybe this is all from the viewpoint of someone who would likely be on the free plan! And so maybe this is a non-issue, but we'd happily pay for this, it just feels like it's a $50/mo service not a $500/mo one.
Yeah that’s a lot. Engineers could spend several hours a month on app size and it would still be cheaper.
App thinning goes a long way if you're supporting multiple architectures, but if your app has a lot of code it can still get very big, very fast. There are many companies that have dedicated teams to trying to handle app size, but we've found that our tooling offers more without the maintenance and eng resource cost of building it internally. To support independent developers and small startups we offer a free Growth plan and have significant discounts available for higher build volumes. We think this is a fair alternative to having a development team or even one engineer focused on this problem.
App size is a problem, but as far as I know only challenge there is cellular download size. (thats why in your examples, dropbox and ebay doesn't care about install size)
Main approach to this problem in industry is when you approach cellular limit, you optimize.
I also agree that it is big engineering investment sometimes. But the problem is you are targeting low hanging fruit (stripping comments from localization, stripping symbols, optimizing images etc) or stuff that doesn't effect download size ( deduplicate files )
Those fixes are good for small startups, which you are giving away for free.
The main engineering problem for big companies is binary size, optimizations like "reordering of the build optimization passes" etc.
I would buy this as a tool, but as a service it is a hard sell for me.
Main approach to this problem in industry is when you approach cellular limit, you optimize.
I also agree that it is big engineering investment sometimes. But the problem is you are targeting low hanging fruit (stripping comments from localization, stripping symbols, optimizing images etc) or stuff that doesn't effect download size ( deduplicate files )
Those fixes are good for small startups, which you are giving away for free.
The main engineering problem for big companies is binary size, optimizations like "reordering of the build optimization passes" etc.
I would buy this as a tool, but as a service it is a hard sell for me.
Definitely! We want to reduce cellular download size as well. In the particular case of Dropbox, their download size is around 100mb right now. I just did a quick test by deleting the duplicate localizations in their Frameworks and zipping the .app which reduced compressed size by ~17mb (17%) so these optimizations would help significantly. This is one of the reasons I prefer to just measure install size. It's difficult to reason about all the combinations, but by reducing install size you're always on the right track to an overall smaller app.
In my experience working on large apps like Airbnb we try to get ahead of the problem even before approaching the cellular limit, since a smaller size helps acquire and keep users, and we want to avoid architecture decisions that would become a problem down the road.
It's not too rare for one of these low hanging fruit optimizations to be accidentally introduced in a large company, with testing on every PR you can catch them before they‘re introduced. Binary size is definitely what changes most often at these large companies and that's why our continuous monitoring lets developers know exactly the granular binary size affect of a PR. With a lot of code, things like exposing Swift functions to Obj-C which introduce new metadata can frequently be mistakenly added. For enterprise companies we also track the biggest modules in their binary, so eng managers can get a better understanding of where the size is coming from.
In my experience working on large apps like Airbnb we try to get ahead of the problem even before approaching the cellular limit, since a smaller size helps acquire and keep users, and we want to avoid architecture decisions that would become a problem down the road.
It's not too rare for one of these low hanging fruit optimizations to be accidentally introduced in a large company, with testing on every PR you can catch them before they‘re introduced. Binary size is definitely what changes most often at these large companies and that's why our continuous monitoring lets developers know exactly the granular binary size affect of a PR. With a lot of code, things like exposing Swift functions to Obj-C which introduce new metadata can frequently be mistakenly added. For enterprise companies we also track the biggest modules in their binary, so eng managers can get a better understanding of where the size is coming from.
It seems technically interesting, but I'm not sure how I can convince my manager that reducing binary size leads to more downloads or sales. @aripickar mentions the Uber app saga, but since then Apple seems to have removed size restrictions on apps downloadable on cellular connections.
I have been using bitrise.io for iOS CI/CD for a few years. I noticed that they added a new step that seems to at least tackle the app size monitoring side of this.
Other than builds being dog slow (fine for me), I couldn’t be more happy with the service and the price ($40/mo. for the single dev plan.)
Other than builds being dog slow (fine for me), I couldn’t be more happy with the service and the price ($40/mo. for the single dev plan.)
That's great to know! This integration is helpful for just knowing the size of an app and being alerted if it goes over a threshold, but it doesn’t provide any insight into where that size actually comes from. Adding a Bitrise integration for Emerge is definitely on our roadmap though!
Can you do it on 3rd party apps or do you need raw access to the build files? I ask because we at MightySignal have an API to provide decrypted APK and IPA files that you could use to run Emerge on any app in the stores.
Thanks, this sounds interesting! Feel free to email me at [email protected]
When you say ‘size’, you mean on disk size or ipa size?
Emerge is designed to help you reduce both! We go into detail on the differences between them (and other ways of measuring size) in our docs: https://docs.emergetools.com/docs/what-is-app-size
I believe the command you give to check if bitcode is enabled is not entirely correct. I was recently debugging an issue where bitcode was not generated for a framework I was using, and my build failed complaining about the framework missing bitcode. While that framework did have `__LLVM` segments, there was no `__bitcode` subsegment.
There’s some discussion around that on this SO question: https://stackoverflow.com/questions/32808642/how-to-check-if... (but also no definitive answer)
There’s some discussion around that on this SO question: https://stackoverflow.com/questions/32808642/how-to-check-if... (but also no definitive answer)
Interesting thanks for sharing! It looks like __bitcode is used for static but not dynamic libraries so it might not always be reliable. I've also found that apps can include bitcode for frameworks but not the main app binary, but if it's included for the main app it is required to be included in frameworks. That's why Emerge checks for the presence of bitcode only in the main app executable.
Well take my dollar and build an app that clears out this "other" storage from iPhone. You would have my top dollar!
Will this problem still exist in 2 years (assuming most users will have 5G and 16GB more storage in their new phone)?
Great question, we've definitely thought about this. Seems like the trends are as users get better tech the apps get more ambitious with their capabilities and performance will always be something worth spending time on.
Looks interesting
What about the image/video transcode to a smaller size?
Thanks! We have some docs on image optimizations here: https://docs.emergetools.com/docs/optimize-images Emerge will automatically compress images as jpg and convert to HEIC and report the size diff do you. We aren't doing automated video optimizations yet but if this would be useful for you please reach out!
Thanks for the detailed answer. My app is a mobile development platform https://twitter.com/acpustudio and has a binary size of 16MB and 33MB are splash screen images, so I am very interested in resource optimization. 16MB binary stripe can save probably a megabyte, but better optimizing the binary can be done with an LLVM AI optimizer like https://facebookresearch.github.io/CompilerGym/getting_start... Media optimization is a huge hole and huge amount of work for you. My suggestion is random codecs and variants where different AI is needed (i'm a little bit ffmpeg expert:)
this looks incredible! Awesome job y'all
whoa this is so sick, nice job guys!
Very interesting! Congrats.
Can't wait to see it
We’re Noah and Josh from Emerge (https://www.emergetools.com). Our company is building a monitoring and analysis tool to help iOS developers reduce their app’s size.
You might have heard about app size challenges faced by large iOS apps, particularly those with Swift codebases. I was an iOS engineer at Airbnb for 4.5 years and personally worked on their size reduction efforts.
App size is tricky to quantify. The size users most commonly see (what’s on the App Store page) is the install size thinned for their device. This is the size measured after stripping out assets like images and other media not needed for your screen size, or code that doesn’t run on your device’s architecture. However, this isn’t the only size metric out there, there’s also download and universal size (read more about this in our docs [1]).
Our tool makes app size easy to understand by visualizing the size contribution of every file in your app, from localized strings to machine learning models. To better our understanding, we even reverse engineered compiled asset catalogs and Mach-O binaries to show size contributions of original images, source files and Swift modules. With this perspective we often see files that don’t belong or are suspiciously large.
While testing our tool we analyzed and learned from over 150 iOS applications and found that keeping app size in check is really hard— even for industry leaders. Here are some of our more interesting findings.
Dropbox (https://www.emergetools.com/apps/dropbox) From the visualization, you can clearly see why Dropbox’s iOS app is 270 MB— it’s 35% localization files. These files are duplicated from the main app into 7 different app extensions and they all include comments that provide translators with context for the strings. Just removing these comments from the production app could save 46 MB.
eBay (https://www.emergetools.com/apps/ebay) This is an interesting architecture because although the main app’s executable is only ~150 KB, 86% of the app’s size comes from executables, the biggest one (32 MB) being EbayApp.framework. When building a Swift framework, the binary contains symbols which are not needed in the build uploaded to the App Store. These symbols can be stripped using the method described in our docs [2]. Stripping binary symbols would reduce Ebay’s app size by over 40%. Emerge can generate a script to add to your Xcode build phase to strip symbols for you.
Spark (https://www.emergetools.com/apps/spark) About 1/10th of Spark’s ~230 MB app is font files. 10 MB of those font files are duplicates found in an app extension. After a closer look, the fonts duplicated are all SF-Pro-Text, look familiar? These have been system fonts since iOS 11 (the minimum version for Spark). If the system font was used directly, 10% of the whole app could be deleted!
If you want to dive in a bit deeper you can check out our Medium post which goes into detail on some other popular apps [3].
Our analysis consistently shows that without guardrails in place, app size can get out of hand very quickly. Emerge wants to help developers reduce their size and keep it that way. Our continuous monitoring and binary size profiling prevents regressions by alerting developers of size changes in their pull requests, helping teams build better, smaller apps.
We offer a free Growth plan designed for independent developers and small startups. Our paid plans start at $499/month, you can view more details here: https://www.emergetools.com/pricing.
If app size has come up in your development process, we’d love to hear about how you handled it. We’re always looking to improve and grow our product and we’re especially excited to hear feedback from the HN community!
Thanks, Noah + Josh
[1] https://docs.emergetools.com/docs/what-is-app-size
[2] https://docs.emergetools.com/docs/strip-binary-symbols
[3] https://medium.com/swlh/how-7-ios-apps-could-save-you-500mb-...