Anyone with Internet access and a computer can learn how to write a few lines of code these days. Free tutorials and information from sites like Codecademy, which has been used by more than 25 million people, offer widespread access to instruction. They might even be able to break down barriers for groups traditionally underrepresented in technology, including women, blacks, and Hispanics.

This open-access model does seem to help—Codecademy says 34 percent of its users are women, for example, nearly double the percentage of female graduates from university computer science programs in the United States.

It’s not uncommon for women to use free programs as a starting point and then seek out women-only groups in their community. One such program is the Women’s Coding Collective, started in 2011 as a Meetup group in Boston by two women who wanted to collaborate on an app and decided to host events to bring together a broader network. Now the group hosts Web development classes that cost $25. Since its first picnic meetings, the collective has hosted 130 events and grown to 6,000 members from all over the world who take classes in Cambridge, Massachusetts, and online as well as attending events and workshops.

San Francisco’s CODE2040, started three years ago, focuses on teaching professional and entrepreneurial skills to blacks and Latinos. Even though 18 percent of U.S. computer science degrees are awarded to members of these groups, their representation in the tech workforce is just over half that level, according to 2012 and 2013 data cited by CODE2040 and the Level Playing Field Institute. At Google, only 2 percent of employees are black and 3 percent are Hispanic. The company just awarded CODE2040 $775,000 in grants to finance new workshops, retreats, and an online platform to help coders and entrepreneurs apply for jobs and expand their businesses.

Shannon Turner, a Web developer, got the idea to start women-only classes when she found herself outnumbered by men at tech events and not always taken seriously. She started Hear Me Code in September 2013 to teach the Python programming language to a handful of women at her kitchen table in Washington, D.C. Since then, the program has grown to 1,200 women who signed up to take four-hour weekend classes every few weeks and meet at informal groups during the week to hone their skills.

Students practice Python for several months, and Turner puts in 40-hour weeks developing the curriculum, mentoring students, planning the logistics for classes, and approving new members, all in addition to her day job as a freelance Web developer. The classes are free, and the group sustains its growth with volunteers. More than 50 students who took the class have now signed up to teach others.

To Turner, the problem with some online coding courses is that they don’t make the content relevant. Her curriculum allows students to write programs for tasks that seem useful, especially to the D.C. crowd. In one of the first lessons, students learn to make a drop-down menu of 50 states that can be used to help organizations make online forms for new members. In another, students write a program that scans two lists of e-mail addresses to pinpoint people who attended both a film screening and a happy hour.

One of the most successful aspects of the program is the way it builds a community of women who learn new skills and then pass them on by teaching in the program or organizing other tech events. Many students participate out of personal interest or to help with their current work, but the classes have even helped some women get new jobs using their coding skills. At least a dozen women have gotten jobs as developers since they took the free Hear Me Code class, for example. One is Sonia Hinson, who initially used Python to coördinate the efforts of her employer, a humanitarian aid organization, to send aid to hospitals. Hinson recently took a new job at a tech company.