Input data is validated by generating code based on the input data. A schema is generated based on the input data indicating conditions for the input file. The schema may then be customized based on a type of application to consume the input data. A validator executable code is generated based on the schema and checks the input file for compliance with the conditions determined by the schema. Results of validation may be provided to the application in yes or no form, or as number of non-compliances. In the latter case, the application may decide to accept or reject the data based on predetermined non-compliance levels.