The number of criminal trials in this country have been on the decline for decades now. According to the American Bar Association, between 1962 and 2002, the number of federal criminal cases decided by trial declined 30 percent—although the number of cases filed actually doubled. From 1979 to 2015, the number of convictions by jury trial fell by more than half. So why has the number of people incarcerated in our jails and prisons not also declined? Why, instead, has the incarcerated population ballooned by more than 500 percent in the past 40 years?

A lot of it boils down to one cause: bail. When people who have yet to be convicted of a crime are forced to pay exorbitant amounts of money to stay out of jail, a lot of them stay in jail, waiting for a trial at which they will be presumed innocent. As Bryce Covert wrote in The Nation last year, “Nationally, arrestees make up 70 percent of the jail population—pretrial detention is a major reason why the United States has the highest incarceration rate in the world. Nearly all of the growth in our jail population over the past 30 years is due to the detention of those not yet convicted of any crime.”

National Bail Out (NBO), a collective of black organizers seeking to end mass incarceration, estimates that the majority of the 700,000 people who languish in local jails throughout the United States each day are there for want of bail money. And for the accused, who are at risk of losing their jobs, their homes, and even custody of their children, each additional day waiting for backlogged court systems to hear their case is another reason to plead guilty, regardless of their innocence.

To give the poor a fairer shot at justice, NBO has collected donations to distribute to local bail funds, which pay the costs of pretrial detention release. Their advocacy has let almost 200 people wait for their trial date at home, rather than behind bars. Now a new online service called Appolition—a kind of mass incarceration abolition app—allows you to help too.

Launched in November, Appolition is a simple way to help: Users—called “Appolitionists” by co-founder Kortney Ziegler—connect their debit or credit cards to the service, which rounds each of their transactions up to the nearest dollar and sends the difference to NBO, as long as it’s 50 cents or more. In turn, NBO distributes funding to 14 local organizations across the country. If the “spare change” model isn’t your speed, Appolitionists can also make one-time or recurring fixed donations through the service’s website.

NBO is not only Appolition’s partner, but its inspiration too. Ziegler tweeted about the idea for the service not long after Mama’s Bail Out Day, when NBO helped coordinate bail payments for more than 100 mothers in time for Mother’s Day 2017. “[We] got so much support and excitement about the idea that we knew it had to be built,” says Ziegler, speaking on behalf of his co-founder, Tiffany Mikell, as well. After four months of development, they approached NBO for the first time to be their partner.

“The only difficulty in the development of Appolition was discovering how many people are ignorant about bail in general,” says Ziegler. Accordingly, Appolition has had to do its fair share of educational work. The service’s launch was complemented with a “Bail 101” webinar hosted by activists who dispelled misconceptions and answered audience questions. Ziegler intends to continue such educational initiatives, while also bolstering the efforts of others working for bail reform.

NBO estimates that, in just three months, Appolition has provided it with $24,000 in funding: $20,000 collected through the service and $4,000 donated directly to the collective by people referred through Appolition. Although NBO does not earmark funds by source, it was able to help Black Lives Matter Cambridge and the Massachusetts Bail Fund free 13 people in time for the holiday season—that is, right after Appolition came online.

While Appolition seems to be humming along just fine, Ziegler acknowledges that there is still much more to do. In the short term, there’s development to be done to allow the service to accept more accounts from different banks and credit unions. Besides that, there are plans to broaden Appolition’s focus to address issues besides bail. For example, Ziegler is currently working on giving Appolitionists the option to donate to a legal fund supporting expungement of low-level cannabis convictions in California.

NBO similarly addresses more than just bail. The local organizations that form the collective also provide short-term housing, health care, transportation, and other services. “Providing folks with transportation money or reminder calls helps them return to court,” says Arissa Hall, a coordinator at NBO.

But the rationale behind providing these additional services is deeper than just ensuring that those out on bail make their court dates. NBO seeks to emphasize empowerment, as opposed to the criminal-justice system’s single-minded focus on punishment. As Hall explains: “Often times when setting bail, court systems will do an assessment to determine if someone poses a risk to their community…. We believe that a person should have a needs assessment, determining what they need to live full lives.”

Both NBO’s and Appolition’s expanding approaches to combating mass incarceration also make sense in light of their ultimate goals. Rather than indefinitely facilitating the system of cash bail by providing for the poor, both seek to end it entirely. After all, efforts like Appolition can only do so much when faced with the $2 billion bail-bond industry. “Our goal is to abolish the cash bail system and pretrial detention,” says Hall; Ziegler, upping the ante, says: “Jails and prisons should be abolished completely.”

Their sentiments hint at bail being only one problematic facet of a thoroughly broken criminal justice system. But until there is more wide-reaching reform, Appolition will continue buying people’s freedom, a few cents at a time.