How similar are the rules of Pathfinder and D&D 3e?

[Mephisto of the FoS]

Hi I found the following book Pathfinder: Occult Adventures and it has some interesting classes for Ravenloft

• Kineticist
  Medium
  Mesmerist
  Occultist
  Psychic
  Spiritualist

How similar to D&D 3e is Pathfider? (This is not a post to be used for promoting what is the best system, I am just wondering if these two systems are compatible).

[Rock of the Fraternity]

They're very compatible.
Pathfinder 1E has also been described as D&D 3.75; it takes D&D 3.5 and makes a number of tweaks.
If you need an online resource to look at, I recommend d20.pfsrd.org.

[Mephisto of the FoS]

https://www.d20pfsrd.com/
Yes I have taken some monsters from that one and checked out some spells and seemed well made as a system.

Thanks

[alhoon]

Pathfinder is practically tweaked 3.5 edition.
When WotC greedily moved to 4th edition which was controversial to downright unpopular in order to make money from its dominance of the market, Pathfinder greedily backstabbed WotC and (ab)using the OGL used their own tools, to become D&D's main competitor by more or less pushing a homebrewed edition of 3.5.

Pathfinder stealing D&D thanks to the (ab)use of OGL is why we will never ever see an OGL like we did for 3.5 edition, for any kind of gaming Intellectual property.

You practically have two sets of evil decision makers trying to exploit the players, decision-makers that were looking at numbers and I bet half of them have never played a single session of D&D or Pathfinder in the past 20 years.
The shift to 4th edition with decision makers from WotC more or less directly ordering Greenwood and Salvatore and other big-names to change the way they do things and write their novels delivered a big blow to D&D.
5th edition steadily regained that trust (Greenwood had confided to some of the others that they should be ready for things to change back as he saw the writing in the wall) from 2014 to... when WotC greed resurfaced a year ago. You can see the threads with the drama over them trying to screw over the small-time producers in here.

[Mistmaster]

PF 1 and D&D 3.5 are strictly connected.

[Pizza]

Pathfinder is practically tweaked 3.5 edition.
When WotC greedily moved to 4th edition which was controversial to downright unpopular in order to make money from its dominance of the market, Pathfinder greedily backstabbed WotC and (ab)using the OGL used their own tools, to become D&D's main competitor by more or less pushing a homebrewed edition of 3.5.

Pathfinder stealing D&D thanks to the (ab)use of OGL is why we will never ever see an OGL like we did for 3.5 edition, for any kind of gaming Intellectual property.

You practically have two sets of evil decision makers trying to exploit the players, decision-makers that were looking at numbers and I bet half of them have never played a single session of D&D or Pathfinder in the past 20 years.
The shift to 4th edition with decision makers from WotC more or less directly ordering Greenwood and Salvatore and other big-names to change the way they do things and write their novels delivered a big blow to D&D.
5th edition steadily regained that trust (Greenwood had confided to some of the others that they should be ready for things to change back as he saw the writing in the wall) from 2014 to... when WotC greed resurfaced a year ago. You can see the threads with the drama over them trying to screw over the small-time producers in here.

As someone whose exposure to DnD comes far more from licensed materials than playing the game, the loss of the novels is such a big blow even when most outside Salvatore and Greenwood were basically cheesy ways to advertise game mechanics.