Here is a list of more or less trustworthy exchanges. Please understand, that the cryptocurrency world is still on its way to become strong and reliable. Some of the popular exchanges (Poloniex, Bittrex) sometimes may ban users or disable withdrawals. Also, the exchanges are at constant risk of being hacked and there is no guarantee that your funds are 100% safe
However, these cryptocurrency exchanges are the ones you can trust today:
- Local Bitcoins - Buy and sell bitcoins near you. Trusted by 10M monthly users.
- Poloniex - USA. Trust: 3.5/5. Tons of altcoins. Poor support.
- CoinBase - USA. Trust: 5/5. Pay with fiat.
- Bittrex - USA. Trust: 4/5. Many altcoins. Responsible founders.
- CEX.IO - UK. Trust: 5/5. Fiat. Newbie friendly.
- BestBitcoinExchange - Curated list of 35 popular exchanges. Looks SEOish but does the job well.
- Shapeshift - No login, fast, awesome API.
- Changelly - Fiat, nice affiliate program.