The Potters went ahead in the first half thanks to a brilliant set-piece which saw Jon Walters make a perfectly-timed run from the far post to convert Glenn Whelan's ball with a clinical finish.
But the Hammers came out fighting after the break and Joey O'Brien proved the unlikely hero as he prodded home Gary O'Neil's cross to level.
Pulis told Sky Sports: "It was chalk and cheese. Two halves, one for us and one for them, so I suppose a draw is a fair result.
"The worst thing that happened to us was half-time. I thought we played really well in the first half and if anything I was disappointed not to come in more than 1-0 up.
"But fair play to West Ham, when they get the early goal it's a fantastic place and stadium to play at. Their crowd really got behind them and we showed a lot of resilience in the second half.
"Give us credit first half, but I thought West Ham were very good second half. They pinned us back and our lads had to defend for their lives."
Pulis admitted his side had been working hard on the set-piece that led to Walters' goal and that they had also employed some questionable tactics.
He said: "We have worked on it for two or three days and never scored a goal in training doing it, but luckily tonight it went for us. It was a great ball in and a great finish from Jon Walters.
"I'm not supposed to say this but we blocked, we obstructed, a player. I'm not supposed to be that honest and say that."
On O'Brien's goal he added: "I have just seen their goal and it's touch and go whether it was offside. I suppose if you are playing at home you hope you get it, away from home sometimes you don't get it."