Bialecki, Klaviyo’s chief executive, and Hallen, Klaviyo’s chief strategy officer, launched their firm in 2012 while Hallen was in his final semester pursuing his MBA at the MIT Sloan School of Management. They met up daily at the Martin Trust Center, and developed strong bonds with other startup founders there.

“I thought, man, this is what entrepreneurship should feel like,” recalled Bialecki, whose software firm is now worth $5 billion on the stock market. “It’s hard. You’re figuring things out. But also, you’ve got other people that are doing it [to collaborate].”

Now, as concerns persist about Massachusetts’ competitive position in the venture capital and startup world, Bialecki and Hallen are hoping to pay it forward with their $6 million pledge to help early-stage startups in the delta v summer program. The infusion will expand the program’s maximum stipend to $75,000 per startup team from $20,000, starting this year, though smaller personal stipends for MIT students are going away. (The funds are not loans or equity investments, but grants without strings attached.)

The donation will also help support more customizing, to better tailor the program for each entrepreneur, as well as a broadening of its professional network, to support mentorship from industry veterans for the participating startups.

“You do have to have an idea but it’s actually not the hard part,” Bialecki said. “The hard part is getting access to folks that really have been through it, that get it. You always want mentors that have seen some things you haven’t seen.”

In particular, Bialecki said he’s encouraged by the freedom that AI provides startup founders, by making it easier to develop software without necessarily needing a deep bench of coders and engineers. He said he considers now to be one of the greatest times “to build in the software industry.”

Bill Aulet, the Martin Trust center’s managing director, said the gift from Hallen and Bialecki represents the largest donation to the accelerator program in its 15-year history. Aulet launched the program, under a different name, to help ensure more promising entrepreneurs stuck with their MIT studies and stayed around Cambridge rather than moving to the West Coast. He envisioned the program as MIT’s answer to Y Combinator, the famous San Francisco startup accelerator that has Boston-area roots.

The delta v program is competitive: Only about one-fifth of the teams that apply, or around 100 students per year, get accepted. Nearly two-thirds of participating teams end up successfully raising funds from outside investors as well, Aulet said. He expects to accept 12 teams this year, or about half of the usual amount, to ensure the new updates to the program roll out smoothly.

The program is being revamped under the direction of Ana Bakshi, the Martin Trust center’s executive director, who was brought in several months ago to oversee the program. Aulet said the program’s main focus will be how to take a business idea and commercialize it, to find paying customers, and have an impact.

Klaviyo, which specializes in marketing technology, is the sort of success story that Aulet would like to see the MIT participants emulate.

“These are two guys who went against the grain,” Aulet said. “They executed, stayed in Boston, and built a great company. . . . If we can get a few more people like them, which I’m sure we will out of this, it makes the world a better place, it makes Boston a better place, it makes MIT better.”

Jon Chesto can be reached at jon.chesto@globe.com. Follow him @jonchesto.