Polypane, The browser for ambitious web developers
92 comments
·March 23, 2025kilian
ashryan
Congrats Kilian!
Polypane made a massive difference in getting our startup's website shipped a few months ago. I highly recommend it for entrepreneur-devs.
parentheses
I recall using your product years ago and it was fantastic. It helped me work solo on a web app with ease. Not having CSS and JS skills like a lot of front end devs, it was nice knowing all viewports were handled.
bsimpson
I built a prototype of something similar with iframes for a gig at eBay a decade ago. Ended up showing it off at the first React conf. Definitely useful to have as much immediate feedback as possible when you're developing.
Glad to see a productized version! Most of my work these days is for internal tools with fixed browser expectations, otherwise I'd probably be downloading a trial right now.
Congrats!
mattlondon
You have the Google logo on your landing page above the fold - what's the connection?
spicybright
I love the idea of the product, I could have definitely used it in the past. And I really love your responses to questions asked here. You're very honest and friendly. If I get into webdev again, I'll definitely give Polypane a shot!
pietmichal
Quick feedback: The "Polypane Portal" page hangs after opening it in Chrome on M1 Pro Macbook.
kilian
Can't seem to replicate that here (m4 macbook), but I'll keep it open for a bit and see what happens. Thanks for letting me know!
katsura
M1 Pro here too, the page doesn't hang, but it's extremely slow to scroll on my end.
janderson215
Have any extensions installed that may be blocking requests?
pulkitsh1234
same
tdhz77
I like your pricing model.
johnisgood
You have to sign up, and then this welcomes me:
The password has to have:
- At least one lowercase letter
- At least one number
- At least one uppercase letter
- At least 8 characters
I do not like it when websites (or applications, w/e) do this. I am somewhat OK with "at least 8 characters long" and I even understand its significance (from a security perspective) but not the rest.
amelius
Just use the browser's built in password suggestion.
dschiffner
zero relevance to the pricing.
herpdyderp
I wish such a browser could accurately emulate a mobile device's browser, not just change screen size, but even Apple's iOS simulator fails at this.
kilian
There's a huge list of things Polypane emulates beyond the screen size.
For devices:
- user agent
- reported platform
- device pixel ratio
- rendering mode (mobile rendering and desktop rendering respond differently depending on your viewport meta tag)
- default input device
- orientation APIs
Beyond that it can also emulate reading direction, page language, browser locale, user-configured default font-size, different network settings and a whole range of different media queries like color-scheme, reduced-motion reduced-data, reduced-transparency, prefers-contrast, forced-colors (windows high contrast mode) and color gamut. I'll be adding even more device browser-specific emulations later this year.herpdyderp
Oh I wasn't even thinking about those things, but that's really cool! I was thinking more about different CSS implementation behavior, though that's less of a mobile-specific issue and more of a "every browser is different" issue.
I don't have a list of differences off the top of my head, but I regularly find big enough differences that I don't rely on "responsive mode" or even (as mentioned) Apple's iOS simulator (because it does not accurately replicate the real on-iPhone browser rendering, which has bitten me before).
kilian
Using Polypane doesn't mean you can skip out on testing other rendering engines. That's such an important point that I even mention it on the homepage!
So yeah, you should be testing (mobile) Safari and Firefox too. Chrome on android has some different APIs compared to Chrome on desktop, but rendering is identical.
When developing your site, you can use Polypane Portal[1] to tunnel your local site to real devices while keeping them fully in sync with what you do in Polypane, so you can scroll, interact, inspect and even edit across real devices from inside Polypane, saving you a ton of time.
no_wizard
Can it emulate email rendering?
avel
You need a farm of machines that run the actual mail clients, to do that reliably. https://www.emailonacid.com/ is such a service.
kilian
no I'm not touching that can of worms with a ten foot pole. Someone braver than me can build that!
Y_Y
No need, nowadays sites just guess you're on a phone if you resize the browser window too narrow and whinge at you to "use a desktop device or use our app for the best experience".
jsheard
> "use a desktop device or use our app for the best experience".
Plot twist: their "app" is just the same site wrapped in a webview, minus the nags to install the app.
codedokode
Plus autostart on boot and daily notifications.
runekaagaard
I've used it a lot. Great product, emulates subtle device issues very well that Chrome device view doesn't
wonger_
Such as?
lofaszvanitt
[flagged]
Ataraxic
The question is that it seems to emulate many things, but what doesn't it emulate well?
It looks like it's built off chromium, so I'm assuming it wouldn't be able to show an issue that only appears in safari or maybe Mozilla?
Perhaps this is in the docs.
edit: It's in the FAQ at the bottom. Still, beyond the actual browser engine, are there other known limitations?
kilian
This feels like a lay-up, but here you go :) https://polypane.app/docs/emulation/#emulation-or-simulation
Polypane doesn't simulate the specific rendering engine of other browsers, it just pretends to be another browser (which is what emulation is) so you can test that the code you wrote for those browsers (for example, a polyfill) responds well. You'll still need to test in those real browsers to check against their rendering bugs or support gaps. (but something like Polypane portal[1] can make that step much easier)
jbreckmckye
Perhaps there's a way you could remotely render a page in Firefox, Safari, etc? And then stream into the viewport.
cantSpellSober
* What are a few features you offer over Browserstack? (re: x-browser testing).
* Do you offer GenAI integrations? (Copilot, Claude, etc)
(Help me sell this to my manager)
kilian
Polypane is a chromium-based browser that you install on your own device and use while building applications that lets you develop at different (emulated) devices and screensizes/variation in one overview, with a bunch of development, accessibility and quality tools built right in.
Browserstack is an online device testing tool where you check if your site works on different real devices one-by-one. That is to say, they don't really compete: if you don't have real devices to test with then Browserstack is an excellent option.
What users mostly find is that by using Polypane (fast, local) they have far less use of Browserstack (slow, online) and the entire process speeds up. There will always be a need for real device testing.
There's no gen AI integrations, and I don't have any planned. You can happily use Claude or CoPilot in the browse panel though (which is a little browser that lives inside Polypane, so you can browse without losing the context of your project)
mattl
Thank you for not adding AI slop to this.
bluetidepro
I really wish the pricing model offered some sort of lifetime purchase. This seems great but I don’t think I could justify the monthly/yearly cost.
tempodox
I would be OK with payed upgrades but a subscription is a big no-no.
tjallingt
Seems quite similar to https://sizzy.co/
herrherrmann
True! I’d love to hear from someone who tried out both and settled on one.
hollin
Sizzy seems to have been abandoned. The developer has been unresponsive and the last update was botched with no way to actually get it. It’s a shame because I preferred Sizzy's experience over the alternatives. It just felt more polished to me.
tonijn
Any free alternative?
mdaniel
The top comment from the last time this was submitted pointed to an open source (AGPLv3) implementation <https://news.ycombinator.com/item?id=29340887> but I don't know how they compare feature-wise
herpdyderp
Wow this is great!
> Responsively App is built on top of Electron and uses Chromium as its rendering engine.
Now I want an app that shows Firefox, Chrome, and Safari side-by-side (besides manually opening them all side-by-side of course).
edoceo
How could one make an app that could host those multiple engines? I've heard that Firefox doesn't embed well, maybe WebKit would be easier? What about Servo or the engine from LadyBird? Is it even possible?
CharlesW
To save other readers a click: https://responsively.app/
hooverd
Chromium
sureglymop
Super cool! Is there the possibility to get a students discount? Will try the free trial for now :)
kilian
Its free for students through the GitHub Student Developer Pack :)
sam_goody
I totally get why you do subscription. I totally get why I don't do subscription.
Is there some sort of middle ground? Say, minimum purchase cost is the same price as six months, but it keeps on working afterwards sans updates. When the dev realizes that such a tool is only 80% effective unless it is totally updated, they can subscribe.
kilian
Happy to answer this. Polypane is a browser. If you don't keep your browser rendering engine up to date, you're opening yourself to a whole host of security issues (not to mention just generally diverging from what your end users use). Keeping that rendering engine up to date means dealing with a slew of potentially breaking changes with each new chromium version.
So there's two reasons:
1. The only way to do that continuous upkeep of the rendering engine that I have found to be sustainable is with a subscription.
2. I definitely don't want to be responsible for people using years-old versions of Chromium.
HWR_14
If my users are using an old version of Chromium, I probably want to support that and test on it.
VyseofArcadia
I liked the old "pay for updates" model. Nowadays, that seems less viable because security updates are so important[0]. I think the middle ground model would be something like security updates are free, feature updates cost money. Something like pay $x for version n+1 or a discounted rate for a subscription.
Sounds like a bit of a hassle on the logistics/release engineering side, though. That would need to be handled with some care and planning.
[0] Which I'll admit I don't 100% buy, but I'd love for a security expert to weigh in.
hombre_fatal
You admit this, but yeah, it's a big headache that has its own trade-offs.
By design, you'll have users spread across any number of versions. And you have to decide how far back you're going to issue updates. And instead of having nice in-app updates and a policy of "just upgrade to the latest version", you have a system that's complicated for you and your users. And you have to decide if you're okay letting users use (by design) releases with issues that have long been fixed.
I can see how Adobe and Jetbrains have the manpower to do it, but a solo dev or a small team, you should spend your time building the dang product rather than appeasing people who don't think your product is worth $9/mo.
VyseofArcadia
Yeah, I've seen similar in pro-level software tools, CAD applications, MATLAB, etc, but those tend to be large and mature organizations with the expertise and manpower to e.g. backport bugfixes to released versions.
IsTom
Maybe it could work similar to how Bitwig licenses work – you buy a license with a year of updates and it's yours – after the year expires you can download binaries for the latest version you're entitled to. Later you can buy access to the current version with an another year of updates (at a lower price) when you've decided that they've added something new you want.
buildfocus
Why don't you do subscription?
I've heard plenty of arguments on the 'financial tools to manage them are bad' (forget about them, hard to cancel) but few against 'paying money proportional to how much I use the product'. As a general concept that seems reasonable to me - if you use a product for 10 years, it's fair to pay more than somebody who uses it for a couple of months.
In a world where finance improves (more subs via Apple Pay et al, more banks like Revolut that show & allow unilaterally blocking any given recurring charge) would you still avoid them?
sam_goody
- It's hard to convince my boss to create a subscription.
- I don't want to become hostage to monthly payments - if I don't pay one month my whole workflow is messed over, so I have to continue (vs. otherwise I can slowly trade it out of my workflow, and/or look for alternatives)
- Its hard for me to mentally grok how much I am paying monthly on subscriptions.
- I never cancel, because inertia.
- I am not sure if this is something that justifies a monthly subscription, and two weeks is too little time for me to invest in changing my workflow to accommodate it.
- I hate subscriptions (this is an emotional thing, so you could tell me to get a shrink. But I suspect I am not the only one).
I feel like I am missing even bigger reasons, but /rantjamesmkenny
I've been using it for a while now. It is an excellent tool in the tool belt, making me a much better developer and more productive, a lot less messing around.
short_sells_poo
I don't understand the many comments here complaining that the browser has a subscription. Finally! I want more paid browsers, not less. I want to get back to a world where we paid for products with money, instead of being datamined and have ads pushed down my throat.
People here, out of all places, should be aware of what it means when a product is free.
elashri
I guess that when people usually talk about paid browsers, they talk about separate web engines not chromium forks. If this will help with the battle against Google's dominance.
charcircuit
Dominance comes from owning the product (the browser), it didn't come from the browser engine.
Hey, I'm Kilian, the creator and solo developer of Polypane. Exciting to see this on the homepage again.
Happy to answer any questions folks have!