Borderlands 4: Complete Vend of the Line Quest Walkthrough
This guide walks you step-by-step through the entire quest, from unlocking it to defeating the vending machine miniboss at the end and choosing your prize. It also covers strategy for the missable "All Things Vend" achievement/trophy, common mistakes players make, and co-op caveats.
What Vend of the Line Is
Vend of the Line is a non-repeatable side mission unlocked in Carcadia Burn after completing the main mission Siege and Destroy. It sets you on a puzzle-filled trail that will lead you to a Legendary Vending Machine - a unique loot source that offers legendary weapons at just 1 cash each. Unlike most vending machines in the Borderlands series, this one is a one-time treasure trove, and how you interact with it can trigger additional rewards or even hidden surprises.
Importantly, the mission cannot be repeated on the same character, so you only get one shot at the legendary reward and at the All Things Vend achievement. This makes understanding the steps and avoiding mistakes critical.
Starting the Vend of the Line Quest
To begin Vend of the Line, you must first finish the story mission Siege and Destroy. Once that's done, head to Carcadia Town in the Carcadia Burn region. Near the main vending machine in that hub, you'll find Penelope Streams - an eager reporter talking with a Vault Gatherer Scout. Speak to Penelope to start the quest.
Once initiated, the first objective will prompt you to inspect the nearby vending machine. Unlike typical quick vending machine interactions, this one hides a puzzle on its backside: a sequence of crossed-out dollar symbols that correspond to item rarities.
Step 1 - Inspect the Starting Machine
Approach the machine and look at its back panel. You'll see icons indicating a specific item rarity sequence: two green (uncommon) signs and two blue (rare) signs. This isn't decorative - it tells you the order of items to sell to the machine to solve its code.
Objective:
Sell the following Borderlands 4 Items in this exact order (one at a time):Green item, Green item, Blue item, Blue item.
Do not use "Sell All Junk" - each sale must be controlled, one at a time, matching the rarity sequence. When done correctly, the machine will glitch, and your map will mark three new vending machine locations with clues.
Step 2 - First Clue: Ruined Sumplands Rooftop Machine
Your first target is a rooftop vending machine located on a small island southwest of Carcadia. The area is hostile, so clear any opposition before climbing up. You'll notice this machine has a power issue. Use a nearby switch (usually on the same building) to activate it.
Once it's powered, inspect the back panel through the gap behind the machine to reveal a color code. The sequence for this machine's puzzle is:Green, Purple, Blue, Green.
To solve it, sell these items to the machine, then use the "Buy Back" feature in the same order to restore them. Each time you complete a vending machine puzzle, you get part of the locator code for the final Legendary Vending Machine.
Step 3 - Second Clue: Crumblehall Machine
Next, travel northeast to Crumblehall in the Grindstone of the Worthy. Here you'll find a vending machine that has fallen over a Vault Gatherer's body. Look at the arrows marked on the machine's back and use them to navigate up the adjacent structure - jumping and climbing up debris - until you reach a ledge with a small window. Peering through this hole reveals the clue: two purple and two orange dollar sign symbols.
This machine's puzzle is handled for you - the crushed Vault Gatherer NPC will automatically input the sequence, so you don't need to sell items yourself. This gives you the next coordinate segment for the legendary machine location.
Step 4 - Third Clue: Lopside Machine
For the third clue, head to Embracer's Buff in Lopside. You'll find a vending machine with a customer trapped near it. Interact with it to start it venting steam; hitting it with a melee attack will dislodge it. You can also attack the customer to make them get out of the way - either way works. Once free, enter the nearby building and inspect the back of the machine.
The code here tells you to sell these items: Green, Purple, Blue, Purple.
When done correctly, this gives you the final part of the coordinate needed to find the legendary location.
Step 5 - Find and Solve the Legendary Machine
With all pieces of the puzzle collected, head to The Dusty Dangler southeast of Grindstone of the Worthy. Clear the area of enemies, then inspect the vending machine on the right side of the building. Checking the back will show a final color sequence, typically: Green, Blue, Purple, Orange.
Sell these items in this order at the machine. This reveals a powered cable running down the cliff. Follow it into a cave beneath the building to find the Legendary Vending Machine.
Boss Fight - Vend Zane
Upon entering the cave, the machine activates and transforms into Vend Zane, a hostile mechanical miniboss. Prepare for a challenging fight: Vend Zane attacks with guns mounted on its frame and summons smaller robotic defenses. Once its health is depleted, it collapses and reveals the Legendary Vending Machine. You can also buy Borderlands 4 Boost to help you fight.
Claiming Your Reward
Now comes the best part - and also the part where many players accidentally ruin the mission. Unlike ordinary machines, this one is scripted: it allows exactly one interaction to claim your legendary weapon reward. If you accidentally sell any item (even junk) before buying your reward, the machine will count that as the one use and shut down, leaving you without a legendary - and since the mission is non-repeatable, there's no second chance.
To avoid this, sell nothing to this machine. Instead, scroll the menu directly to the Legendary weapons section, and choose one - they all cost 1 cash. If you aren't satisfied with the offered stock, wait 30 minutes in real time or reload the game to refresh the stock before buying.
Optional: Unlocking the All Things Vend Achievement
There's a secret step here that unlocks the rare All Things Vend trophy/achievement if done correctly. After defeating Vend Zane but before buying your legendary, look around the room - you'll find a wooden board on the ground with a pattern of crosses and dollar signs (three green and one orange). This board hints at a special sequence.
To unlock the trophy, perform these actions in order: Sell three green items, Buy one orange (legendary) item.
This sequence won't prevent you from getting your chosen legendary, and it grants an additional photo item that advances a minor side objective involving Zane's story.
Co-op and Common Pitfalls
If you're playing in co-op, be aware only one player can claim the legendary reward once the machine is activated. Others in the group may be locked out afterward because the mission completes on all connected players' profiles. Coordination is key.
Also resist the instinct to hit "sell junk" at the final machine - doing so can prematurely lock the machine and prevent your reward.
Conclusion
Vend of the Line is one of Borderlands 4's cleverest and most rewarding side missions. It combines puzzle solving, platforming, exploration, and combat, culminating in a chance to pick a Legendary weapon for just 1 dollar. It's worth the effort - and the careful attention - because it's non-repeatable and can give you a powerful boost for your Vault Hunter's build. Whether you're playing solo or in co-op, understanding each step and avoiding common errors will ensure you walk away with the loot you deserve.