The widespread popularity of online trading among all types of traders have given rise to a variety of brokerage firms. Today traders can trade almost all financial instruments including stocks, bonds, commodity futures, options, funds, currencies, and much more online, from the comfort of their own home. Online trading brokers offered much fast order execution for less charges and made available a range of trading tools which once were available to only institutional and large scale traders. There are many different kinds of classifications of online trading brokers, here are some important ones.

Classification based on products is the one of the most popular. Here brokers are classify according to the access to products they are providing. They include

1. Stock trading brokerage firms - brokers whose main service is to trade equities. Most brokers you heard about are primarily stock brokers.
2. Forex trading brokerage firms - these are brokers who offer traders access to the worlds biggest financial market, forex currency trading market. Forex brokers tend to differ from others, as they do not charge any straight commissions, instead they profit from spreads between ask and bid price for a currency pair.
3. Futures trading brokerage firms - these brokerage firms which allow traders to trade commodity futures. They can be of many subclasses of brokers who specialize in equity futures, currency futures, financial futures, energy futures, commodity futures, etc.
4. Options trading brokerage firms - these are brokers whose primary trading service is for options, an interesting instrument having different underlyings such as stocks, futures, funds, bonds or currencies which offer a traders a option to buy/sell or not to buy/sell the underlyings at a future time.
5. Funds trading brokers - includes brokerage firms which offer traders access to many mutual funds, treasury notes, bonds and Exchange Traded Funds.

But the above classification, other than forex and futures brokers, is not a clear one as most brokers allow traders to trade many products and markets. One other popular way of classification of online trading brokers is according to their trading service(s).

1. Online full-service brokers - these are traditional brokerage firms which start offering online trading services. They allow traders to trade a vast variety of products and markets; offers more order types, and plenty of trading services. In return, they charge often high but they are well-informed of market movements and are very good in customer support.
2. Discount brokers - they usually offer the same number of services as full-service brokers for a remarkably low charge. They highly automate their trading services. But one can never expect the same level of market knowledge, trading assistance and customer support from them.
3. Deep discount brokers - they tend to offer lowest commissions but almost fully automating the trading procedure, even customer support. Often the traders will be limited with the number of markets and products they can trade.
4. Day trading brokers - also known as direct access brokers, they provide traders real-time access to markets. Products and markets can be limited but they offer some of the most powerful trading systems which tremendously help in active trading.

To find the broker who best suit one, he/she must consider many factors which include trading style, products/markets, profit goals, risk-tolerance, commissions payable, order types, account specifications, past performances, accessibility, platform, and much more.