As a Turkish Citizien
If it is ?stanbul. No you don't have to worry about anti-semetism.
The biggest threat you could face is getting into a dioalog with a total ignorant.
Just stay away from some places like "Fikirtepe" as they are dangerous for everyone.
But places like Taksim,Be?ikta?,Kad?k?y and the rest of ?stanbul (Taksim is the place which synagogue is) are just fine.
By the way most of turkish people have a sympathy for Tourists. I mean when you go to a restaurant, if the waiter understands that you are a foreigner.You can have a very funny conversation with his funny accent.
(When I say tourist no matter which nation and religion and I assure you racisim rate is much more lower than europian countries.)
and do not let anyone sell a carpet to you...
(An expression gained from the answers above: People really like to speak about facts which they have no idea about, and don't believe every thing you saw on the internet.)
It's a truly massive city of around 20 million people so there are bound to be a few idiots.
But unless you're an Orthodox Jew or unless you're semi-orthodox and wear a yarmulke all the time, nobody is going to know, and even if they do find out the overwhelming majority of Turks won't care at all, especially if you're spending money.
Enjoy your visit. If you can try to stay right in the ancient centre at Sultanahmet, you're then a short walk from the Blue Mosque and Agios Sophia and can beat the coach party crowds. I highly recommend the Mavi Ev (Blue House) hotel if you can afford it.
People are not hostile to Jews in Europe, don't be absurd. They may be a little narky to Israelis, but honestly, given the bad press the Israeli government has created in recent years in relation to the Palestinian community, is it any wonder?
Here's the thing: unless you go flaunting your religion to the world in general, NOBODY IS GOING TO KNOW WHAT IT IS. And what's more: even if they do find out, most people WON'T CARE.
If they are stupid enough to advertize they are Jewish in a country where a majority blame and hate their entire country for one isolated event which took the lives of 9 Turkish people there will be a lot more stupid and prejudice people who will openly express their racist opinion of them. And yes it could explode into violence. Best their identity is kept under wraps.
There is more anti-Muslim sentiment and protest in Europe than anti-Jewish feeling. Turkey is justifiably upset with Israel for killing 9 Turkish citizens during the Freedom Flotilla. It is really anti-Israeli but that can turn into anti-semetism.
There are Jews living in Turkey find them and ask
We restored and rebuild the biggest synagogue in the europe. So what the f.ck are you talking abou?