Brilliant.org
Subscription app teaching math and science through interactive, hands-on problems.
On the record
Checkpoint: Koji's rollout into Calculus courses, a test of whether the AI tutor lifts retention
The call
Brilliant built a real library of interactive lessons, but free AI tutors and Khan Academy's own AI now offer the same style of teaching at no cost.
Brilliant.org makes interactive math and science lessons where you solve problems step by step, with hints along the way. The company built its own visualizations and interactive tools over 14 years, which is harder for others to copy quickly. But now free AI chatbots like ChatGPT and Claude can give the same hint-based help for free, and Khan Academy (which is free and nonprofit) already offers similar lessons plus its own AI tutor called Khanmigo. Brilliant.org's team has shrunk 17 percent from its peak, and it has not raised new money since 2022. The one thing that could turn this around: if Brilliant's new AI tutor, called Koji, keeps students coming back better than Khan Academy's free version does, especially when Brilliant launches new calculus lessons in the second half of 2026.
Why
01
AI pressure: ChatGPT, Gemini, Claude. Free chatbots now walk students through problems step by step, copying Brilliant's core hint-based teaching method at no cost. Could AI do the core job? Yes, likely.
02
Bigger players: Khan Academy. Khan Academy is free, nonprofit, and already ships its own AI tutor Khanmigo, sitting on the same students Brilliant charges for. Could a giant copy it? Yes, easily.
03
What protects it. 14 years of hand built interactive visuals and sliders that its new AI tutor Koji can manipulate, which plain chatbots cannot easily copy.
What would change this call
Brilliant announces a new funding round or acquisition talk by end of 2027. Would show investors believe Koji creates durable retention worth backing.
Headcount and traffic trend past mid-2026 (currently ~106 staff, ~1.2% QoQ traffic growth). Continued decline would confirm shrinking business; reversal would suggest stabilization.
Reported retention or ARPU data tied to Koji's Calculus rollout (H2 2026). Would show whether proprietary content plus AI actually keeps users better than free alternatives.
Headcount and traffic trend past mid-2026 (currently ~106 staff, ~1.2% QoQ traffic growth). Continued decline would confirm shrinking business; reversal would suggest stabilization.
Reported retention or ARPU data tied to Koji's Calculus rollout (H2 2026). Would show whether proprietary content plus AI actually keeps users better than free alternatives.
Key numbers
- Headcount down to 106 from peak 128
- Website traffic growing just 1.2% per quarter
- No new funding round disclosed since 2022
Named risks
- Core Socratic-tutoring value proposition replicable for free by ChatGPT, Gemini, Claude.
- No funding round confirmed since 2022, limiting resources to compete with better-funded rivals.
- Headcount declined from peak 128 (April 2024) to 106 (June 2026), growth score 2/100.
- Ranked 10th in EdTech AI visibility index, risking reduced organic discovery via AI answer engines.
- Koji tutor itself built on third-party models (Gemini, ElevenLabs), weakening claim to a proprietary AI moat.
Rivals, as read in July 2026
| Rival | Direction | Evidence |
|---|---|---|
| Khan Academy | losing to | Free nonprofit with Khanmigo AI tutor already shipped; ranked above Brilliant in AI visibility index, 2026-06-10 |
| Duolingo | losing to | Duolingo Math occupies adjacent gamified learning niche, ranked top-tier in AI visibility index, 2026-06-10 |
| Coursera | losing to | 2022 data shows Coursera at $383.6M revenue and $3.1B valuation versus Brilliant's much smaller scale |
| Codecademy | contesting | Repeatedly named as Brilliant's nearest peer in interactive coding education comparisons, 2026-05-20 |
| ChatGPT/Gemini/Claude (frontier chatbots) | losing to | Free Socratic tutoring now native to general chatbots, commoditizing Brilliant's core value proposition |
Questions people ask
- Is Brilliant.org profitable?
- No public profitability data exists. Growjo estimated 2022 revenue near $18.3M, but Brilliant.org has disclosed no profit figures, and headcount fell from a peak of 128 in April 2024 to 106 by June 2026, suggesting cost tightening rather than confirmed profitability.
- Could AI replace Brilliant.org?
- Brilliant's core offering, hint-based Socratic problem walkthroughs, is now natively available free in ChatGPT, Gemini, and Claude. Brilliant's own Koji tutor, launched June 8, 2026, runs partly on Gemini, meaning its differentiator sits atop the same models threatening to commoditize it.
- Who is Brilliant.org's biggest competitor?
- Khan Academy is Brilliant's closest threat: it is free, nonprofit, and already ships its own AI tutor, Khanmigo, built on OpenAI. A June 2026 5W EdTech AI Visibility Index ranked Khan Academy, Duolingo, and Coursera above Brilliant, which placed 10th among tracked EdTech brands.
- Who owns Brilliant.org and has it raised new funding recently?
- Brilliant.org is privately held and venture-backed, led by CEO and co-founder Sue Khim as of June 2026. No confirmed funding round or valuation event has been reported since a Series C, disclosed by different trackers as $15M in 2020 or $50M in May 2022.
- What is Koji, Brilliant.org's AI tutor?
- Koji, launched around June 8, 2026, is described by Brilliant as the world's first graphical AI tutor. It can see a learner's on-screen work, sketch and annotate, and ask guiding questions instead of giving direct answers; it uses Gemini and ElevenLabs voice technology.
- How many users does Brilliant.org have?
- Brilliant.org states it has 10 million or more learners globally as of 2026, a figure the company reports on its own site. An earlier third-party Apple profile from July 13, 2023 cited over 9 million registered users and nearly 2 million monthly active users.
Timeline
- 2026-06-30Brilliant publishes blog post detailing Koji, its graphical AI tutor
- 2026-06-26ElevenLabs confirms it powers Koji's voice layer, cites Gemini use
- 2026-06-19Crustdata reports headcount at 106, down from peak 128 in April 2024
- 2026-06-105W EdTech AI Visibility Index ranks Brilliant 10th behind Khan Academy, Duolingo, Coursera
- 2026-06-08Koji AI tutor launch publicized; CEO Sue Khim discusses it on This Week in Startups
- 2024-04Brilliant.org headcount peaks at approximately 128 employees
- 2022-12Brilliant acquires Hellosaurus, an interactive kids' video platform
- 2022-05Series C reported at $50M by one tracker (conflicts with $15M 2020 figure)
- 2019Brilliant.org valuation reported at $50 million
- 2013Series A of approximately $10M led by Social Capital (Chamath Palihapitiya)
Revision history
22 July 2026
First assessed. Losing its protection. The text above is fixed as of this date and is not edited afterwards.
In the same band
Sources
- Brilliant (website)
- Brilliant.org, Headcount, Funding & Open Jobs (2026-06-19)
- Revenue, Competitors, Alternatives (2022-04-16)
- Learn by doing
- She Makes Math Fun. Here's the Proof! (2023-07-13)
- Brilliant.org Teams
- A world-class tutor in every home (2026-06-30)
- Brilliant launches personal tutor powered by ElevenLabs (2026-06-26)
- Product Features - Help Center
- Brilliant
- Best Online Learning Tools... (2026-05-20)
- Duolingo and Khan Academy Dominate EdTech AI Visibility (2026-06-10)