Independent app studio · Korea
AI that works with you,
one to one.
o2one is an independent app studio in Korea. We build focused AI apps for the moments you have to speak for yourself — interviews, presentations, negotiations — and for the everyday work in between.
- Founded
- Apr 2025
- Apps shipped
- 9
- Flagship
- AI Interview
About
One problem, one app, done properly.
Most people don't need another all-in-one platform. They need help with one specific thing, right now: an interview on Friday, a pitch next week, a negotiation they keep putting off.
So we build small, sharp tools. Each o2one app does one job end to end, works the way a good coach would — one to one — and gets better with every release.
o2one was founded in April 2025 by Jung Chang Hwan, who builds and publishes all of our apps.
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Practice, not theory
Our coaching apps make you do the thing — answer out loud, present, negotiate — and then show you exactly what to fix.
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Feedback you can act on
Every report points to a specific sentence, habit or gap, not a vague score.
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Ship, listen, repeat
We release often and change our apps based on how people actually use them.
Flagship app
AI Interview
A mock interview coach for new graduates and career changers. It reads your résumé, asks the questions an interviewer would, listens to your spoken answers and tells you what to improve.
- Paste your résumé. Get questions tailored to your role and experience.
- Pick your field. Engineering, marketing, planning, cabin crew and more.
- Answer out loud. Questions come one at a time, like a real interview.
- Review the report. A transcript of your answer plus feedback on structure, clarity and evidence.
Currently available in Korean.
Your résumé mentions a payment system rebuild. Walk me through one technical decision you made yourself.
“I moved failed-payment retries from synchronous calls to a queue. At peak hours we were seeing timeouts…”
- StructureGood
- ClarityFair
- EvidenceAdd
Your reasoning is clear. Add one before-and-after number — failure rate or response time — to make the evidence stick.
Apps
Everything we've shipped.
Nine apps since August 2025, all published by o2one on the Korean App Store. Newest first in each group.
Speaking & careers4 apps
- Coding Interview CoachPractice developer interviews and technical questions2025.09
- AI Negotiation CoachRehearse a negotiation before it happens2025.09
- AI Interview FlagshipRésumé-based mock interviews with spoken answers and AI feedback2025.08
- Speech TalkTalkSpeaking practice for interviews and presentations2025.08
Learning & productivity3 apps
Contact
Get in touch by email.
- Partnerships & business
- [email protected]
- App support
- [email protected]