This couple vibe coded a bot to call 20,000 gas stations. They're building a price tracker from scratch.

• A couple built a US gas price tracker using Claude Code and AI agents that called 20,000 stations.
• It stacks gas prices with regional delicacies — like Dunkin' coffees and college football tickets.
• The calls show how people react to AI in the wild. Most answer, some hesitate, and a few swear.

"Hey, I'm Bobby from Gas Index, I'm an AI. What's regular goin' for today?"

"Say it again?" an attendant from Manhattan responded — before telling the bot the sign above the station was flashing a $3.89 price for a gallon of regular.

"Perfect, thanks," Bobby said before hanging up.

That's one of nearly 20,000 conversations between a gas station attendant and an AI agent — named Bobby after a character from the animated sitcom "King of the Hill" — created by Matt Cortland and John Fleming.

Cortland and Fleming, a married couple based in London, shipped a website and a phone bot as a passion project on Monday. It's called Gas Index.

It touches on several trends colliding at once: vibe-coding AI tools that speed up software development, rising fuel costs amid the war in Iran, and a new class of bots interacting directly with people in the real world.

"It seemed like a relatively new way of getting up-to-date information," Cortland, who has family in New Jersey and works as a consultant, told Business Insider. "We thought, 'What's the thing that could be really impactful for people?' We arrived at gas prices."

Fleming, a UK-based postdoctoral researcher at Oxford University, said their app reveals a significant difference in American regulations.

On Wednesday, the national average for regular gas is $4.16, according to AAA, but prices range widely — from $3.43 in Oklahoma to $5.93 in California. In the UK, by contrast, the couple found average regional prices differ by just three cents nationwide.

"The US is trying to fill a gap," Fleming said. "In the UK, it's a gold standard system. People in petrol stations have to update their prices every half hour and make it publicly accessible."

How does the gas spike compare with a Dunkin' iced?

Gas Index tracks more than 170,000 stations across all 50 states, with a marriage of data sets. It starts with location and pricing data from Google — but the tech company's dataset covers only about half of US gas stations, according to the founders, with stronger coverage among large chains.

The app aims to fix that coverage gap with updates where Google's pricing API doesn't reach.

To get more data, Gas Index relies on user-submitted photos of pumps and receipts and AI-generated phone calls to stations that don't report prices elsewhere.

Cortland and Fleming said the website was built with Claude Code over three days, while contributions from tools like ElevenLabs, Twilio, and Supabase helped build the phone bot and manage the data in another two days. The couple said the push to build the site's last 10% was "very intensive."

They estimate their AI token receipts for the project between $3,000 and $5,000.

"You spend for every call you make," Cortland said. "When you're making this many calls, the price really starts to go up. We did get a grant from ElevenLabs, which gave a ton of credits. If we didn't have that, it would have been way more expensive."

Gas Index also tries to translate rising gas costs into everyday terms.

Take, for example, a Toyota Camry owner in Alewife, Massachusetts. That driver can enter their car and location to see how much more they're paying to fill their tank — expressed in regional delicacies like Dunkin' iced coffees or fluffernutter ingredients.

Nebraska's gas prices are compared to the price of a ticket to attend a Husker college football game. Louisiana's is weighed against the price of a Cafe Du Monde beignet. New Hampshire's is stacked up to a pint of maple syrup.

Still, accuracy varies. Because the comparisons depend on user-submitted data, which the founders said will improve over time, they have built-in checks to weed out "bad data" from users.

Business Insider spot-checked 10 stations listed on the site by calling them directly. Four matched the listed price, while one differed by 15 cents. Gas prices can change multiple times per day, leading to discrepancies depending on when the data is collected.

Responding to an AI call

Bobby called a lot of stations. Their responses varied.

"I can go outside and check real quick," one cashier in Texas told the AI, according to transcripts provided by Cortland and Fleming. "I'm walking outside right now. So right now, our regular gas is $3.49 a gallon, and diesel is $4.99 a gallon."

Several others were less enthusiastic. Cortland says that one in every 700 calls features some profanity.

The calls also revealed regional differences. Texas was the hardest state to reach by phone, they said, while only 20% of stations in New Jersey shared prices after picking up the receiver.

Independently owned stations were the most willing to disclose their current prices, they said.

A war's impact on fuel costs

The site also frames price increases around the war in Iran, which it references repeatedly on its homepage.

"What's the war costing you specifically?" a read-out at the top of the site says. "Gas is up $1.13 a gallon since the Iran war began."

But the founders said they want everyone to use their new project, and don't want to be seen as nakedly political.

"The goal here is just to get people to try to get better pricing for stuff," Cortland said. "We want people in Democratic and Republican states also to use this, because it can be helpful for everyone."