The Profile
Neha Mittal
She added the word “just” to a Twitter notification. Then she built a company so no one waits six months to do it again.
CEO & co-founder, JustAI. Still shipping.
She added the word “just” to a Twitter notification. Then she built a company so no one waits six months to do it again.
Neha Mittal runs JustAI, the San Francisco startup formerly called Just Words, where software writes, tests, and rewrites marketing copy without ever getting tired of it. Her job today is to make the slowest, most human part of growth marketing - finding the right words - happen continuously, at machine speed, with a person still holding the wheel.
Marketing teams have a quiet bottleneck: one or two copywriters, and a near-infinite list of things to test. Every push notification, every subject line, every landing-page headline is a small experiment, and there are never enough hands to run them all. Mittal lived inside that constraint at two of the internet's busiest products. JustAI is her answer to it.
The platform auto-refreshes content across email, SMS, push, and landing pages. Under the hood it leans on reinforcement learning and causal inference to figure out which words actually moved a number, then feeds that back into the next draft. The pitch is plain: turn months of A/B testing into days, and let the system run the experiment that the team would have run if it had ten times the people.
What she is careful to keep is the human. JustAI is built around a human-in-the-loop model where the machine handles creation and optimization and the marketer sets strategy. The slogan she keeps returning to is a shift in posture more than a feature list: stop thinking in campaigns, start thinking about the person on the other end.
When Mittal led growth at Twitter, her team changed a push notification from “Elon tweeted” to “Elon just tweeted.” That single word - just - added a sense of now, and roughly 800,000 users showed up. It is the kind of result growth people dream about.
The frustration was everything around it. Shipping a change that small could take three to six months of meetings, approvals, and testing windows. So her team built internal automation to generate and run these tests faster, and it produced about 20% additional user growth. She saw the same wall again at Pinterest, where she headed Retention and Growth. The pattern was unmistakable: the words mattered enormously, and the org could never test them fast enough.
That gap - between how much copy matters and how slowly companies can iterate on it - is the thing she left to go build. Just Words launched in early 2024 and joined Y Combinator's Winter 2024 batch.
A bachelor's in computer engineering from the National University of Singapore, then distributed systems at Goldman Sachs. Mittal started by learning how big systems behave under load.
She left the pure-engineering track for a master's at UC Berkeley's School of Information in 2019, chasing a deeper read on user needs - not just how systems work, but why people respond.
Founding engineer at SensorFlow, co-founder of CityStructure, growth lead at Twitter and Pinterest, and now CEO of JustAI. She has worn nearly every startup hat there is.
We use reinforcement learning to build a continuous loop of creating better content over time.
The human-in-the-loop approach ensures that only high-quality content reaches users.
I get bored easily. I have this constant urge to try new things and always be shipping.
We're trying to go to a world of user-centric focus rather than campaign-centric focus.
Mittal's bet on the future is that marketing stops being a one-way megaphone. Instead of blasting the same campaign at everyone, systems will hold something closer to a one-to-one conversation, choosing the message, the timing, and the channel for each person - and learning from the reply.
The funding behind that bet is roughly $2.2M in seed money, with backers including Cloud Capital, Peak XV Partners, and Y Combinator. Early enterprise clients - names like Coursera, Thumbtack, and Tumblr - have used the product to lift open rates, click-throughs, and conversions.
The through-line from Goldman to Berkeley to Twitter to JustAI is consistency of temperament more than title. She gets bored. She wants to try the new thing. She wants to ship. The company is, in a real sense, that restlessness turned into a product - one that is engineered, fittingly, to never stop iterating.
The entire company traces back to one four-letter addition: “just.”
Engineer, founding engineer, co-founder, CEO - she has held them all.
Her chops were forged on distributed systems at Goldman Sachs before marketing ever entered the picture.
Computer engineering in Singapore, then a master's at Berkeley, then a startup in San Francisco.
“Always be shipping” is less a slogan than a personality trait that became a roadmap.
Profile assembled from public sources. Facts only - the rest is just words.