Verification Vs Validation

Verification:
Verification ensures the product is designed to deliver all functionality to the customer;

Verification ensures that the application complies to standards and processes. This answers the question " Did we build the right system? "
Eg: Design reveiws, code walkthroughs and inspections.

It typically involves reviews and meetings to evaluate documents, plans, code, requirements and specifications; this can be done with checklists, issues lists, and walkthroughs and inspection meetings.

Checking documents for defects(I mean to say uncovered requirements). Here no code will be executed. Before buliding actual sytem this checking will be done. This process will be called verification or Quality Assurence.

Verification is a process in which information is checked using accurate measures.
E.g. when you enter a new password you are asked to retype it to verify that the password supplied is correct.

Validation:
Validation ensures that functionality, as defined in requirements, is the intended behavior of the product;

Validation ensures whether the application is built as per the plan. This answers the question " Did we build the system in the right way? ".
Eg: Unit Testing, Integration Testing, System Testing and UAT.

Validation typically involves actual testing and takes place after verifications are completed. Where as Validation concern, checking will be done by executing code for errors (defects.). This also can be calles as Qulity Control.

Validation however is the automatic process in which rules are applied in order to make information correct,
E.g. if the right type of data is entered in a certain cell in a database.

“Verification is done through out the life cycle of the project/product where as validation comes in the testing phase of the application”.