CLEC (Colombian Learner English Corpus) is a Corpus of Learner of English as a foreign language. The corpus is made up of 600 compositions of argumentative texts from English learners of basic, intermediate and upper intermediate levels. The total number of running words is approx. 200.000. The Corpus was tagged using error tagging UCLE software from the Université de Lovaine. This web app is useful for English teachers in Colombia to know statistics on most common errors of Colombian Learners and find examples. Thank you very much to those students who gave their permission to use data for the doctoral research and the Universidad del Norte for giving special attention and permission to carry out the project. Data is used anonymously to protect students’ identity. Data is used solely for research purposes. Feedback on data interface, or general comments can be emailed to Victoria Pardo, Gabriel Quiroz or Antonio Tamayo.