The Builder Base is the second base for you to progress after you reach Town Hall level 4. This is a completely separate base with a few ties to the main base which you were previously playing. However, the advantages are not balanced, progressing in the main base doesn’t help with builder base at all whereas progression in the builder base can benefit the main base. The main reason why you want to play the builder base is because of the “OTTO” which is basically your 6th builder in the game. You can unlock him within 6-10 months of starting the game which will accelerate your main base progress.
You can only gain loot every day from winning 3 times, in addition to collector loot. This is very removed from the main base where you can farm unlimited loot every day. Builder base is gated by resources whereas the main base is gated by time. This means you need to maximize your loot gain. To do this, you need to be in high leagues because the loot you gain is determined solely by your trophy level and builder hall level. There is no reason to stay in low leagues unless you want to stress-free builder base experience.
Matchmaking in the builder base is completely different from the main base. The entire system can be summarized to, “the only important thing is your trophy count”. If you are at 1800 trophies, your enemy will be around 1800 trophies as well, regardless of BH level. You can be BH4 and still face BH8-9 if they are at a lower league. This means it is greatly disadvantageous to be a lower level. You can all the incentive in the world to be a high level, so that you have an advantage over lower levels. By growing stronger than your enemies, you can go higher in leagues and gain more loot to progress faster overall.
The AI and pathing in this game mode is quite different from the original game. Do practice a bit before raging out. Giants and barbs are more likely to go into funnels than to break walls. A lot of times, it seems that the AI is very dumb, but in reality its the ingenuity of base designers to exploit the different AI here so that troops get trapped.
Offense and resource buildings are far more important than defenses here. You can easily get 100% each battle and get a win whenever your enemy makes a mistake. Do not be afraid of ties unless you are really high cup range for your base.
Additional reading: The four pillars of clash (to be written, google it for now)
Building a defense adds a huge amount of dps, but upgrading them only improves their dps by 10%. So that means that building new defenses is more important than upgrading them. Likewise, adding a new army camp increases your army by 20-33% instantly, very few troop upgrades can match this improvement.
As you can read from the above, the smart player will realise that rushing is still the best way to go in this game mode. So much so that it is dumb to max out and anyone in reddit will recommend you to rush in the builder base. The funny thing is, every single advantage of rushing can be translated to the main base as well, in fact rushing is stronger in the main base. Yet we see so many haters against people who rush, I don’t understand the maxer mentality at all.
The most important advice in the builder base is “rush to BH9 asap”.