Gig workers are fighting back.

By their name, you might think independent contractors are a motley crew — geographically scattered, with erratic paychecks and tattered safety nets. They report to faceless software subroutines rather than human bosses. Most gig workers toil alone as they ferry passengers, deliver food and perform errands.

But in recent weeks, some of these app-wielding workers have joined forces to effect changes by the multibillion-dollar companies and powerful algorithms that control their working conditions.

Last week, Instacart shoppers wrung payment concessions from the grocery delivery company, which had been using customer tips to subsidize what it paid them. After outcries by workers on social media, in news reports and through online petitions, San Francisco’s Instacart said it had been “misguided.” It now adds tips on top of its base pay — as most customers and shoppers thought they should be — and will retroactively compensate workers who were stiffed on tips.

New York this year became the first U.S. city to implement a minimum wage for Uber and Lyft, which now must pay drivers at least $17.22 an hour after expenses ($26.51 before expenses). Lyft, which sued over the requirement, last week gave in to driver pressure to implement it.

For two years, drivers held rallies, released research, sent thousands of letters and calls to city officials, and gathered 16,000 petition signature among themselves. The Independent Drivers Guild, a union-affiliated group that represents New York ride-hail drivers and spearheaded the campaign, predicted per-driver pay boosts of up to $9,600 a year.

That follows some other hard-fought worker crusades, such as when they persuaded Uber to finally add tipping to its app in 2017, a move triggered by several phenomena: a string of corporate scandals, the fact that rival Lyft had offered tipping from the get-go, and a class-action lawsuit seeking employment status for workers.

“We’ll probably start to see more gig workers organizing as they realize that enough negative publicity for the companies can make something change,” said Alexandrea Ravenelle, an assistant sociology professor at New York’s Mercy College and author of “Hustle and Gig: Struggling and Surviving in the Sharing Economy.” “But companies will keep trying to push the envelope to pay workers as little as possible.”

The current political climate, with tech giants such as Facebook and Google on hot seats over privacy, abuse of customer data and other issues, has helped the workers’ quests.

“We’re at a moment of reckoning for tech companies,” said Alex Rosenblat, a technology ethnographer at New York’s Data & Society Research Institute and author of “Uberland: How Algorithms Are Rewriting the Rules of Work.” “There’s a techlash, a broader understanding that tech companies have to be held accountable as political institutions rather than neutral forces for good.”

The climate also includes more consumer awareness of labor issues in the on-demand economy. “People are realizing that you don’t just jump in an Uber and don’t have to think about who’s driving you and what they make,” Ravenelle said. “There’s a lot more attention to gig workers’ plight.”

Instacart customers were dismayed to discover that their tips were not going to workers on top of their pay as a reward for good service.

Sage Wilson, a spokesman for Working Washington, a labor-backed group that helped with the Instacart shoppers’ campaign, said many more gig workers have emerged with stories of similar experiences on other apps.

“Pay transparency really seems to be an issue across many of these platforms,” he said. “I almost wonder if it’s part of the reason why these companies are building black box algorithmic pay models in the first place (so) you might not even know right away if you got a pay cut until you start seeing the weekly totals trending down.”

Cases in point: DoorDash and Amazon also rifle the tip jar to subsidize contractors’ base pay, as Instacart did. DoorDash defended this, saying its pay model “provides transparency, consistency, and predictability” and has increased both satisfaction and retention of its “Dashers.”

But Kristen Anderson of Concord, a social worker who works part-time for DoorDash to help with student loans, said that was not her experience. Her pay dropped dramatically after DoorDash started appropriating tips in 2017, she said. “Originally it was worth my time and now it’s not,” she said. “It’s frustrating.”

Instacart workers had similar feelings — and turned them into concerted actions.

“This has been a maddening, frustrating and, at times, incredibly disheartening experience,” said Debi LaBell of San Carlos, who does weekend work for Instacart on top of a full-time job. “When I first started doing Instacart, I loved getting in my car to head to my first shop. These past few months, it has taken everything that I have to get motivated enough to do my shift.”

Before each shopping trip, she hand-wrote notes to all her customers explaining the tips issue. She and other shoppers congregated online both to vent and to organize.

Her hope now is that Instacart will invite shoppers like her to hear their experiences and ideas.

There’s poetic justice in the fact that the same internet that allows gig companies to create widely dispersed marketplaces provided gig workers space to find solidarity with one another.

“It’s like the internet taketh and giveth,” said Eric Lloyd, an attorney at the law firm Seyfarth Shaw, which represents management, including some gig companies he wouldn’t name, in labor cases. “The internet gave rise to this whole new economy, giving businesses a way to build really innovative models, and it’s given workers new ways to advance their rights.”

For California gig workers, even more changes are on the horizon in the wake of a ground-breaking California Supreme Court decision last April that redefined when to classify workers as employees versus independent contractors.

Gig companies, labor leaders and lawmakers are holding meetings in Sacramento to thrash out legislative responses to the Dynamex decision. Options could range from more workers getting employment status to gig companies offering flexible benefits. Whatever happens, it’s sure to upend the status quo.

Rather than piecemeal enforcement through litigation, arbitration and various government agencies such as unemployment agencies, it makes sense to come up with overall standards, Rosenblat said.

“There’s a big need for comprehensive standards with an understanding of all the trade-offs,” she said. “We’re at a tipping point for change.”

Carolyn Said is a San Francisco Chronicle staff writer. Email: csaid@sfchronicle.com Twitter: @csaid