For building relationship with customer is very difficult task, for this purpose need sophisticated CRM solution. CRM is a best solution for sustaining business customer relationship. (Customer Relationship Management) is web based software solution, it is use for record customer contact no. customer transactions, customer sales purchase history and customer detailed information for future perspective.
Open source CRM is a free of cost customer relationship management solution. Any one modify open source CRM according to their needs. No need to buy expensive commercial CRM solution. If you have technical experiences you can modify with no cost, if you do not have any technical expertise you can customize it from freelancer developer at cheap rate as compare to commercial CRM.
Lets we see the top 5 open source CRM solution which are numbered according to their unique features and based on user satisfaction.
1.SugarCRM

SugarCRM is very famous open source customer relationship management software solution. It was found in 2004 by the trio of John Roberts. This Software applications is written in PHP and its also work with Microsoft sql server database and mysql database. SugarCRM is use for multipurpose in business, It can be use as a marketing tool, customer information storage, analyzing and reporting. SugarCRM has two version one is commercial and other one is open source. Hosted version of SugarCRM is commercial version while Community version of SugarCrm is free and opens source.
2.Vtigar

Vtigar is also open source customer relationship engagement software solution, is actually based on SugarCRM. Vtigar was a part of SugarCRM but now it is independent. Therefore most of the functions of both CRM is same but few functions like management task,integration are missing. Vtigar is a suitable choice for small and mediums businesses. Vtigar can be download on your own server or you can purchase hosted version of vtigar in a very reasonable price.
3.ZohoCRM

ZohoCRM is another free open source CRM software solution for managing customer leads.ZohoCRM is free for only 3 users and store 5000 records of user. ZohoCRm has a mobile application you cans easily manage records by your mobile. The most useful things about ZohoCRM is easy to use and development features.
4.Bitrix24

Bitrix24 provide free 12 user account and 5 GB storage and also provide free hand to do anything with this storage. Bitrix24 provide unlimited user account and fifty gig storage capacity only $99.This deal is very reasonable and Bitrix24 provide flexibality if you want to add more storage its provide this option. Like ZohoCRM it is very easy to use CRM solution.
5.FreeCRM

FreeCRM is a web based opens source customer relationship management software solution available one year free account. This CRM provide 5 user account free of cost and in which 2500 customer contacts included. This CRM provide up gradation very affordable rates. This software do not provide customer support in free account.