Is this the most broken spell? You could summon anything to you, with no save, into an extremely devastating trap. Would this not wreck any high-level game where either the bad guys or the party just picks enemies off right and left?

1. It costs 5000gp per pop.

2. it’s a 9th level spell. 

Don’t make enemies capable of spam casting expensive 9th level spells. If you already have one, make preparations. 

It does not say that the material component is consumed. I understand it's a 9th level spell, but a high-level PC could prepare a trap (perhaps in a demiplane) then gate a big bad in and pretty much just win.

Again: it’s a 9th level spell. 

9th levels spells are like that 

Personally I'm not big on the "it's a 9th level spell" rationale for it being game-breaking. Lots of 9th level spells are powerful, even OP, but this one seems like an order of magnitude worse than any of the others.

It’s only game breaking if you let it be. If you’re putting enemies up against characters with access to 9th level spells who are prepared for characters with 9th level spells, your encounter balances are off. Any BigBad worth the title at that level would have countermeasures in place. 

You are the target.

Your enemy knows Gate.

Precaution 1: Always stay on the same plane as your enemy. Gate only works if you're on different planes.

Precaution 2: Always use pseudonyms and titles for yourself. Never let your enemy know your real name. Gate won't work.

Precaution 3: Remain inside an Antimagic Field whenever possible. You can't be teleported out of the field.

Precaution 4: Contingency - Dimension Door as far away as possible if you're ever teleported anywhere against your will.

And that's just off the top of my head.

Quote from TheCubester >>

You are the target.

Your enemy knows Gate.

Precaution 1: Always stay on the same plane as your enemy. Gate only works if you're on different planes.

Precaution 2: Always use pseudonyms and titles for yourself. Never let your enemy know your real name. Gate won't work.

Precaution 3: Remain inside an Antimagic Field whenever possible. You can't be teleported out of the field.

Precaution 4: Contingency - Dimension Door as far away as possible if you're ever teleported anywhere against your will.

And that's just off the top of my head.

Those are only somewhat sustainable - in the long run something is gonna crack or slip. "Be on the same plane" is easier said than done if someone can hop to another plane and then cast Gate and it's impossible to scry on someone 24/7. Someone will know your real name at some point, be it a family member or someone you've met way before you thought about living the life of paranoid reclusive in an antimagic field (rotfl).

No4. is solid advice though.

Don't forget about this line:

Deities and other planar rulers can prevent portals created by this spell from opening in their presence or anywhere within their domains.

That gives a DM full rights to say "the spell doesn't work" whenever they feel like it.

Quote from Emmber >>

Don't forget about this line:

Deities and other planar rulers can prevent portals created by this spell from opening in their presence or anywhere within their domains.

That gives a DM full rights to say "the spell doesn't work" whenever they feel like it.

This conversation makes me want to read the World of Tiers series again. It's old, but is the best depiction I've seen of beings with god-like powers trying to trap and kill each other. Each ruled their own pocket dimension and would set elaborate traps to foil their rival's powers.

Quote from Lathlaer >>

Someone will know your real name at some point, be it a family member or someone you've met way before

 Only if you allow them to live.

Right, this is exactly the type of nonsense I'm talking about. It turns the game into hiding out in antimagic fields and going your entire adventuring career under a pseudonym because you're paranoid about gates when you get to tier four (which, commune and contact other plane, and a variety of other abilities get around). Anyone who can cast gate is likely to have access to the demiplane spell or the plane shift spell, so the different planes restriction is meaningless. Even number four fails when you're talking about demiplanes. They're 30' cubes. You're not going to get very far. Trapped-up demiplanes make gates basically auto kills on targets.

Quote from MasterOfConflict >>

Trapped-up demiplanes make gates basically auto kills on targets.

 Only if you haven't taken precautions.

That's the game.

If your game isn't broken by the time your players have 9th level spells, it will be very soon.

Just out of curiosity, can spells be cast through a gate?

For example:

A villain escapes through a gate spell in front of the players. Villain's allies shoot a fireball through the gate to prevent the party from following. Would the villain's allies be able to do so? It doesn't say in the spell's description that you can't cast through it.

Quote from RedHood5229 >>

Just out of curiosity, can spells be cast through a gate?

For example:

A villain escapes through a gate spell in front of the players. Villain's allies shoot a fireball through the gate to prevent the party from following. Would the villain's allies be able to do so? It doesn't say in the spell's description that you can't cast through it.

in general yes 

incredibly techinically-confused screaming 

planar distance is weird so if the spell has a range it may or not work depending on various factors 

but if you dont like lore/rule specifics yes it would work unless the spell your casting does not work on another plane

The spell isn't showing up for me is there a book I need to get 

Quote from TheoPeriwinkle >>

The spell isn't showing up for me is there a book I need to get 

 
No, it's free. You need to be a 17th level Cleric, Sorcerer or Wizard.