Undertale Adventures X Codes

Most rewards from these codes are named after things from the original Undertale, so they can look confusing if you are new to the game. This is what each type of reward means for your team:

• Trait Rerolls: units in Undertale Adventures X can be made stronger with traits, and a reroll gives a unit a new random trait. Rerolls are the biggest part of the milestone codes, since landing a good trait on your main units can take many attempts.
• Souls: one of the game's currencies. MOREFREESTUFF adds 1,000 Souls straight to your balance.
• Soul Fragments and the Bravery Vial: items from the Halloween code. Bravery is one of the seven human soul traits in Undertale, which is where the vial gets its name.
• Temmie Flakes, Glamburgers and Face Steaks: named after the healing food you can buy in Undertale. In Undertale Adventures X, Temmie Flakes come in numbered tiers, such as Temmie Flakes III and IV.
• Gaster Hands: named after W. D. Gaster, the mysterious scientist hidden in Undertale's files. Both milestone codes and MOREFREESTUFF include them.

Reward lists can change if the developers edit a code after release, so the items above are what players received at the time of our last check. The table at the top always shows the reward we confirmed for each code.

If the game rejects a code, go through these checks before you give up on it:

• Capital letters: codes are case-sensitive, so 6KCCUREWARD will not work if you type it in lowercase. The Copy button avoids typos.
• Missing symbols: older codes like 2KCCU! end with an exclamation mark, and leaving it off makes the code invalid. Copy the whole code, including punctuation.
• Extra spaces: a space before or after the code can make it fail. After pasting, check both ends of the text box.
• Old server: a code released with an update only works on servers running that update. Join a different server and try again.
• Expired code: codes are removed without notice. If a code still fails after all of the checks above, it has most likely expired, and it will move to the expired list once we confirm it.

You may still see 2KCCU! and FREESTUFF! listed as working on some sites. When we checked, one code tracker still showed them as active, but most others had already moved them to their expired lists, and the newer milestone codes have taken their place. Since the majority of reports say they no longer work, we keep them in the expired section rather than send you to try them first.

The same goes for THANKYOUFORWAITING, an older thank-you code that several trackers now list as expired. If you have time to spare, there is no harm in trying an expired code, but redeem the four active codes first so you do not miss anything that still works.

Undertale Adventures X is a Roblox tower defense game based on Undertale, made by Side Productions. The game used to be called Undertale Adventures TD, which is why some older guides still list its codes under that name. Its official description sums up the loop: defend your base from monsters using Undertale units, then level up your units and make them stronger with traits.

Instead of generic towers, your units are characters from Undertale. You place them along the path, upgrade them as the waves get harder, and try to keep the monsters away from your base until the last wave. Outside of matches you level up your favorite units and reroll their traits, which is where the Trait Rerolls from codes come in.

Its Roblox title currently carries a RELEASE tag, the official description announces that Undertale Adventures X is now live, and the game regularly has thousands of players online at the same time. That player count is exactly what the milestone codes celebrate.

Side Productions releases codes at three kinds of moments. The first is player-count milestones: CCU stands for concurrent users, and the names of 5KCCUREWARD and 6KCCUREWARD point to the game reaching 5,000 and 6,000 players online at the same time. The second is events and seasons, such as PREPAREFORHALLOWEEN for the Halloween update. The third is regular updates, which often come with a thank-you code.

The developers announce codes in the official Side Productions Discord server, where update logs are posted, and in the Side Productions group on Roblox. Because milestone codes appear as soon as the player count is reached, new ones can show up on any day, not only on update days. We re-check this list regularly, and the Last updated date at the top tells you when the list was last confirmed.

Redeem new codes as soon as you see them. Codes expire without notice, and event codes such as PREPAREFORHALLOWEEN usually stop working once the event is over.

Save your Trait Rerolls for units you plan to keep. Rerolling a unit you will replace in a week wastes the most valuable part of each code, so pick one or two main units and focus your rerolls on them.

Finally, keep an eye on the expired list. If a friend shares an old code, you can check here first instead of typing it in and wondering why nothing happened.

We check Undertale Adventures X codes by hand. A code goes into the main table only when at least two independent sources agree on it, or when it comes straight from the official game description or rules. Codes that only one source reports, or that sources disagree on, are kept in a separate unconfirmed table, so you can still try them without mistaking them for confirmed codes. A code moves to the expired list once it is reported as no longer working.

This page was last checked on October 20, 2026. We never make up codes or rewards, and we keep a list of the sources behind every code. If something on this page no longer matches what you see in the game, tell us with the Feedback button and we will check it again.

Every code is listed exactly the way the game expects it, with the same capital letters, numbers and symbols, so the safest way to enter one is the Copy button next to it rather than typing it by hand. A code that turns out to be wrong is moved to the right table, never silently deleted.