An efficient mob farm is a fully dark platform placed 24 to 128 blocks away from where you stand, with every other spawnable surface in that range lit or removed, and flowing water to push mobs into a kill chamber. Get those three things right and the design details barely matter; get any of them wrong and no amount of clever redstone will save your rates.
The rules below have not changed in any major way for overworld spawning since 1.18, and they remain current as of 26.2. There is exactly one mob that ignores all of it — the Creaking — and we cover that at the end.
The three rules that decide your rates
Light level 0
Hostile mobs spawn in the overworld at light level 0. Not "dim" — zero. A single stray light source, including one you brought with you, removes a chunk of your spawning floor. In the Nether, the threshold is a light level of 7 or below; that figure comes from a secondary source rather than the primary wiki page, so treat it as reliable-but-unconfirmed.
Spawn range: 24 to 128 blocks
Mobs spawn no closer than 24 blocks from a player and no further than 128. This is the rule most failed farms break: the platform is too close, so nothing spawns, or too far, so it's outside the range entirely. Your AFK spot is part of the build, not an afterthought.
The mob cap
The server or world enforces a limit on how many hostile mobs can exist at once. If mobs are spawning in caves elsewhere, they consume that budget and your farm starves. This is why spawn-proofing or distance from other spawnable space matters as much as the farm itself.
Step 1: Pick a location and spawn-proof it
The two ideal locations are over an ocean and high in the sky, for the same reason: nothing else nearby competes for the mob cap. If you build on land or near caves, you'll spend far more effort lighting or slabbing the surrounding area than you spent on the farm — and you'll still lose spawns to whatever you missed.
Step 2: Build the spawn platforms
Each platform needs at least two blocks of headroom so mobs can actually spawn. Stack multiple platforms vertically to multiply your spawnable area within the same footprint, keeping the whole stack inside the 24–128 block band from your AFK position. More platforms means more surface area competing for the same mob cap, so there is a point of diminishing returns.
Step 3: Water canals
Place a water source every 8 blocks so the flow carries mobs the full length of the platform to a central drop. Sign and trapdoor tricks let you hold water back at the drop point without breaking the flow — the standard technique for turning a flat platform into a funnel.
Step 4: The kill chamber
The simplest reliable killer is fall damage: drop mobs far enough that they land on one or two hit points, then finish them by hand for the XP. Hoppers underneath feed drops into chests. If you're farming XP specifically to repair gear, our guide on how to get Mending fast covers whether that's even the efficient route for you.
The Creaking: the one mob you cannot farm this way
The Creaking, added with the Pale Garden in 1.21, breaks every assumption above. It's tied to a Creaking Heart in Pale Oak rather than spawning on dark blocks, and it only moves while unobserved. There is no conventional farm design for it. If you came here looking for one, the honest answer is that it can't be farmed by these methods.
A note on villager builds
If your farm project includes villagers, be aware that the baby mob model changes in 26.1 are community-reported to have broken some breeder designs — babies no longer fitting through gaps that previously worked. That's multiple corroborating player reports, not an acknowledged bug, so test before you commit. Our villager trading hall guide goes through the workarounds people are trying and flags which ones are unverified.
Troubleshooting a slow farm
- Nothing spawns at all: you're inside the 24-block minimum, or a light source is on the platform.
- Low but non-zero rates: nearby caves are eating the mob cap. Spawn-proof or move.
- Mobs stuck on the platform: water source spacing is wrong, or the flow doesn't reach the far corners.
- Rates dropped after an update: copy the world and test rather than rebuilding — version changes have broken farms before.
- Works in singleplayer, not on a server: server mob caps and simulation distance are configured differently.
Where this stops mattering
Everything above is vanilla behaviour. Servers that rewrite mob behaviour — MCRPG included — change spawn rules, mob stats and drop tables, so a vanilla farm design may produce very different results or none at all. Check the server's own rules before investing a week in a build.