Spare rooms are no longer just for guests and Airbnb. The lucrative room-letting business has inspired a new way of housing ex-inmates as the United States tests a raft of innovations to ease prisoner release, when a place to call home is a top priority yet often the hardest thing to find. Ex-prisoners say the freedom and security they get from a room of their own is a huge turnaround after a decade-plus of bunking up in crowded jails, and an opportunity to start afresh.

"I had my own room, for the first time in over 10 years," said KC Matthews, among the first to benefit from the Airbnb-style, post-prison programme.

"It provided me a safe space, my own space, and provided me stability _ to do the other things I needed to do," he told the Thomson Reuters Foundation by phone.

Since August 2018, the Homecoming Project has been matching people due to leave prison with local hosts with spare space in Alameda County, outside San Francisco.

Researchers, advocates and policymakers increasingly say that safe and stable housing is critical to helping prisoners adapt to life in the outside world - and to staying there.

Traditionally, prisoners fended for themselves on release - a challenge that pushes many back into jail - or enrolled in transitional housing programmes with heavy restrictions.

Now different cities are trying new ways to help inmates slot back into life, and housing is one of their key tools.

For Matthews, a transgender man who had lived on the streets and in foster care for much of his life, his anxiety grew ever more acute as his release date neared.

"Is there a place that will accept me and where I will be comfortable?" said Matthews, 51. "This was weighing me down at a time I should have been happy - I was getting out of prison!"

Which is where Homecoming came in.

It paired Matthews with a potential host, then gave them opportunities to talk by phone before his release. It worked.

When he got out, Matthews said he was able to apply immediately for a driving licence, social security card and other necessities: critical errands that he said would have taken him a month under traditional transitional housing rules.

He was also able to ease back into the rhythms of life out of prison - re-learning how to shop for food and more - while his temporary home offered a safe haven as he adjusted.

"That was one less thing on my plate - housing and safety," he said.

The Homecoming Project works only with people jailed for at least a decade, said Terah Lawyer, project coordinator at Impact Justice, a nonprofit that runs the initiative.

"If you're gone for 10 years, you come back completely a ghost," she said, referring to inmates whose driving licence, credit history and identity papers get erased.

"It was inspired by the Airbnb model and realising that _ anyone who has the money can stay at an Airbnb without anyone checking their record, but getting their own housing is complicated," she said.

By placing ex-prisoners with community hosts and mentors for six months, the pilot project bypasses the tight restrictions of state transitional housing and helps inmates re-integrate.

"The community hosts are going to be role-modelling what life is like in the community for participants," Lawyer said.

For prisoners to get any home on release is complicated. In large urban areas, half of those released each year face homelessness, according to a 2016 report. Almost 50,000 people go directly to shelters on release, according to federal data.

"The period after release from prison is about the most extreme poverty you can imagine," said Wanda Bertram with the Prison Policy Initiative, a nonprofit.

Money aside, she said, inmates need new ID, as well as find a landlord who will accept tenants with a criminal record and a place that meets their own often onerous parole requirements.

Those who have spent a single stint in prison are seven times more likely to experience homelessness than the rest of the U.S. population, and those who have been jailed multiple times are 13 times more likely to be homeless, according to a first-ever national estimate that PPI put out last year.

There is no national data, Bertram said, but recognition of the issue has broken into the 2020 presidential campaign.

Former vice president Joe Biden, now a top-polling candidate for president, has said that if elected he will "set a national goal of ensuring 100% of formerly incarcerated individuals have housing upon re-entry" from prison.

There is also a fledgling legal push underway to scrap rule-bound screening processes that can deny would-be tenants any shot at renting a home if they carry a criminal record, even prohibiting stays with family members.

Since the federal government highlighted the issue in 2016, 10 municipalities have enacted what are known as "Fair Chance" policies, said Deborah Thrope, supervising attorney with the National Housing Law Project, a legal advocacy group.

"This is the first time people are really taking a hard look at screening policies, especially around affordable housing," said Thrope.

Another 2020 presidential candidate, Senator Kamala Harris of California, has floated a proposal that would make local Fair Chance strategies apply to federal housing policies.

It would mark a major change from the old ways, experts say.

"What generally happened when we released in Georgia historically is you'd get $25 and a bus ticket to wherever you came from," said Tom McElhenney, director of transitional services for the Georgia Department of Corrections.

Those released in such a way "go into survival mode and go back to what they can do to survive, which is usually dealing drugs and other illegal" activity, McElhenney told the Thomson Reuters Foundation by phone. "We want to break that cycle."

Last year, the state prison system started a project in Atlanta to do just that - the Metro Reentry Facility.

The standalone facility puts prisoners nearing release through an intensive programme of life skills and vocational classes, certification courses and more, seeking to ensure that when they leave, they have a job and a home, McElhenney said.

That means working closely with housing providers and updating inmates' ID - a common barrier to getting on.

It also offers a space where family members can get to know each other again. "A lot of those released go and live with family members," said McElhenney. "Your best chance for success is with someone who knows you and can support you."

So far about 80 people have gone through the Metro Reentry Facility, and the state wants to set up similar operations outside of Atlanta, he said. "We hope this will reduce recidivism and are confident it probably will."