Can I use Discord browser version on my iMac G3?

Which model G3 iMac are you referring to? The oldest models (233, 266, and 333 MHz G3 processor speed) had a tray-loading optical drive, while the models with a 350, 400, 450, 500, 600, or 700 MHz G3 processor had slot-loading optical drives. While it would seem preferable to get one with a faster processor, the slot-loading iMacs had no internal cooling fan and the envisioned convection cooling proved to be inadequate for preventing heat-related damage. The essential power hub of those iMacs, the "Power-Analog-Video" (PAV) Board, eventually failed on many of them. When that happens, the iMac ceases to power on and is useless.

As someone who owned 3 slot-loading iMacs, and now just 1, the PAV board failed in 2 without any warning. Since the average user has no recourse for repairing it, it's e-cycle material at that point. So I wouldn't recommend purchasing an iMac with a 350 - 700 MHz processor in 2025. Internet use for any 26-year-old computer, whether a Mac or PC, is unrealistic. If you want to have a G3 iMac because of its unique case design and can lower your expectations as to planned usage, I'd look for a 333 MHz model that has an internal cooling fan. Keep in mind that the fan provides no guarantee as to the remaining service life of a 26-year-old electronic device. You could be wasting your money for a very limited amount of enjoyment.

ahhmiata wrote:

I’m about to purchase an iMac G3. I’m wondering if Discord via Google would work?

Do you really mean that you are about to purchase an iMac with a PowerPC G3 chip? Apple sold various models of those between August 1998 and January 2002. None of them can run anything later than Mac OS X 10.4.* (Tiger), and some cannot run that. All of those Macs are basically of historical interest, or of use for preserving old games, and not much more than that.

Or did you mean that you were about to purchase a 24" M3 iMac? That would be a fairly recent iMac sold between November 2023 and October 2024 that has a third-generation Apple Silicon M3 chip. That Mac originally shipped with macOS 13.5 (Ventura), can run 15.* (Sequoia), and will be able to run 26.* (Tahoe) when that comes out this fall.

ahhmiata wrote:

I don’t see it saying I can’t use Discord via a browser.

Browsers that are compatible with a PowerPC-G3-based iMac will have trouble accessing just about any modern Web site. Both security standards and presentation standards have changed over the course of 20+ years. Just the https security changes alone might lock you out of just about all modern https Web sites.

An Apple Silicon Mac with a M3 chip can run the latest versions of Safari, Firefox, Brave, et al.

So which chip we are talking about here makes a rather critical difference.

You can't run a browser modern enough to connect to anything useful on a G3 iMac. Web security standards have evolved about four generations since that computer was produced.

According to their website, they require macOS 11 (Big Sur) or later and that will not run on a G3 iMac. See: https://support.discord.com/hc/en-us/articles/213491697-What-are-the-OS-system-requirements-for-Discord

The slot-loading G3 iMacs did have a faster (100 MHz) bus speed than the original tray-loaders, a slightly better graphics chip, and could support up to 1 GB of PC-100 or PC-133 SDRAM with (2) 512 MB DIMMs. Replacing the original IDE hard drive with a larger capacity one (120 GBs) was a typical upgrade and made the iMac whisper-quiet. The hard drive has the older/discontinued 40-pin ATA interface, that was phased out with the introduction of SATA drives. The slot-loading optical drives often developed a nuissance quirk, so that they couldn't completely pull the disk into nor fully-eject it out of the drive. A pair of rubber-clad rollers inside the drive begin to dry out with age and lose their grip because their surface becomes slick. Manual assistance is required to push in or remove the disk. The 2 front speakers also degrade over time, tearing apart along the cone's outer surround that originally flexed when new. A moderate to loud volume setting can quickly tear it from repeated vibrations. I saw that happen while playing a music file.

Before installing Mac OS X on a slot-loading iMac, you need to run the "iMac Firmware Update 4.1.9," that was usually found on the retail "universal installer" Mac OS X disk (Jaguar, Panther, or Tiger). The hook is that the firmware update requires that you be booted from the internal hard drive that's running OS 9. If the firmware update has already been done, the Apple System Profiler will indicate the firmware version and you won't have to bother with it.

When I invested the money to upgrade a pair of slot-loading iMacs as described, it was around 15+ years ago. Knowing what I do about the unreliability of the PAV board and its inevitable failure, I wouldn't consider it today.