Searching for the best karaoke host software usually means you run the show. Score the tools on the job, not on a living-room catalog. Auto-KJ is Paul Kircher's commercial host app. The public names are the Free version ($0) and the Full version (about $10 a month, or $500 for lifetime access to the Full version). It is not open source, and it does not include a song catalog.
This is a buyer's guide, not a ranking. It does not score products this site has not measured, and it does not invent download counts or win rates. Two comparisons are already published if you are shopping a specific alternative: Auto-KJ vs KaraFun Pro and Auto-KJ vs Siglos. Use those pages for that choice. The criteria below are the part that stays the same no matter which name is on the laptop.
1. Whose files play
Host software either plays a library you already own, or it rents a catalog. Those are different purchases. If you have years of MP3+G and ZIP tracks, you want a program that indexes those folders and leaves the files on your drive. If you do not own tracks, a catalog rental may be the shorter path, and this site's KaraFun comparison is the write-up of that split.
Auto-KJ is the bring-your-own-library side. The karaoke software page covers the formats the site states: video karaoke in .mp4, .mkv, and .avi, plus CDG/ZIP and an MP3+G library. You are responsible for the rights to play those files in public. Canceling a subscription does not take the files, because they were never ours.
2. Whether you can explain the rotation
The argument at 11:30 is who sings next. Useful karaoke host software lets you state the rules out loud: first come, where a late arrival sits, what a duet costs, what a skip does, and whether the host takes a normal slot. The written version of those rules is karaoke rotation rules.
In Auto-KJ that job is the Fairness Engine. A late arrival takes the first seat that does not push anyone else back. Duets account for both names. A pause does not take the stage. A skip closes the gap. Changing the song keeps the seat. You can still drag anyone. The homepage has a rotation simulator you can break before you install. That is the mechanism. It is not a claim that every singer will agree with you.
3. How singers ask for a song
Paper, a name typed at the desk, or a phone. Phones are not free on every product, including this one. The Free version is desk-entered only. The Full version adds singer phones in the browser at singer.auto-kj.com. Singers search, see their place, and request. They find the show by GPS, a show code, or the venue LAN. There is no app-store app.
If the night is still a clipboard, start there. A printable sign-up sheet matches the desk workflow. Phones are the upgrade when you want the room to see the same list you see.
4. What happens when the venue network fails
Ask this before you depend on a stream. Playback of local files should not need the bar router. Requests might. Auto-KJ keeps song files on the booth computer. The Full version can fail over to a LAN mid-show when the venue internet drops. The Free version never needed that network, because you type the list. Details are in karaoke in a bar with terrible Wi-Fi. The site does not describe cloud singer requests working with no network at all.
5. Which computers it runs on
Match the installer to the laptop you carry. Auto-KJ publishes Windows x64, Windows ARM64, Apple Silicon, Intel Mac, and Linux x64 packages. The pages are karaoke software for Windows, Mac karaoke software, and karaoke software for Linux. The site does not publish minimum RAM, CPU, or operating-system version numbers.
6. What the free tier actually includes
Read the free tier as a product, not as a demo timer. Auto-KJ's Free version is $0, with no account required to download. It includes the desktop app, Fairness Engine rotation for songs you enter at the desk, your files, and a dual screen. It does not include singer phones. The Full version trial is 60 days, started inside the app, with no card and nothing that bills automatically, one trial per account and per computer. After the trial, the library and show data stay on the Free version.
Monthly Full version is one live show at a time. Another simultaneous show is $5 a month. That is shows at once, not how many nights you work. Ghost-Trax credits are $2 on the Free version and the Full version. They are not a song catalog.
7. Whether open source is the requirement
If the requirement is free-forever open source, Auto-KJ is the wrong answer. It is a supported commercial product. It is not an OpenKJ release, and it is not built on OpenKJ. OpenKJ is the open-source host program. You can keep running it and add songbook hosting for $5 a month or $50 a year, or that hosting is included with the Full version. The songbook does not unlock the Auto-KJ desktop app. Both paths are on the OpenKJ alternative page.
Where Auto-KJ fits
Choose Auto-KJ when you own the files, you want the rotation rules above, and you are fine with a commercial app from one developer. Start on the Free version if phones can wait. Start the Full version trial if the room should request from browsers and the venue network is unreliable. The product page is karaoke host software. Bar and venue owners have a shorter version at karaoke software for bars.
Skip Auto-KJ when you need a licensed catalog, an app-store singer app, or a program you can fork. Those are real requirements. They are not this product. Questions go to support@auto-kj.com, and the short answers are on the FAQ.
Check the criteria against the app
The Free version download does not need an account. The Full version trial starts in Settings, then License Activation. No card.