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Posted by alexsouthmayd 20 hours ago

Launch HN: Bloomy (YC S26) – AI-powered mastery learning for K-12

Hi HN, I’m Alex Southmayd, the founder of Bloomy (https://bloomylearning.com) – an AI-powered mastery-learning platform for K-12 students. Bloomy provides students with an AI tutor alongside adaptive curriculum (right now Math, English Language Arts, and Writing).

How it works: we diagnose students’ skill gaps, place them on personalized learning paths, and give them standards-aligned lessons and a Socratic AI tutor that scaffolds their learning without just giving away the answer.

The goal is to solve the Bloom 2-sigma problem (https://en.wikipedia.org/wiki/Bloom%27s_2_sigma_problem) with AI.

Short launch video: https://tinyurl.com/bloomylearning

Longer product demo: https://youtu.be/XHvoKt6qMeo

Families access for Bloomy: https://bloomylearning.com/families

I started as a teacher. I taught 7th-grade English and writing with Teach For America, and every day I struggled to deliver differentiated instruction to 30 students with 30 different sets of needs. Some students needed remediation, some needed acceleration, and many needed a tutor sitting next to them helping them reason through the next step. Benjamin Bloom’s two-sigma result—that one-on-one tutoring can produce much better outcomes than conventional classroom instruction—always felt intuitively true to me. The hard part was making that kind of attention affordable and available to every child.

Then AI changed the cost curve. When I saw schools such as Alpha organize academics around mastery rather than seat time, the model clicked. If you’ve heard of Alpha School, that is directionally the kind of learning model that inspired us. But I kept thinking about the families and schools that already exist: homeschool families, microschools, hybrid schools, and regular classrooms where most children are today.

Most students and teachers see learning gaps at the wrong resolution. They get a grade, percentile, benchmark score, or broad standard—not “this is the next skill this student should learn.” Existing personalized-learning products often feel like digital worksheets: they provide plenty of practice, but not much diagnosis or teaching. Very few have AI tutors providing the core instruction. Bloomy starts with a diagnostic—we integrate with third-party assessments and provide our own—and creates a learning path for each student. Students work one skill at a time, receive a short lesson, practice at an adaptive difficulty, and only move forward after demonstrating at least 90% mastery. The learning path updates as the student works, based on their performance and our knowledge graph of skill prerequisites (built in collaboration with Learning Commons / Chan Zuckerberg Initiative).

Each skill has three stages. Base Camp teaches the concept with worked examples. Climb provides guided practice and Socratic support. Summit is an independent ten-question mastery assessment with no hints or AI assistance. Students need to achieve 90% on the Summit to advance. If they struggle too much, they’ll be routed to a different skill better suited for their level.

BloomyBot is not a blank chat window but rather a live, interactive, and observant digital tutor. During practice, it receives the active passage or problem, the question, the student’s attempt, an authored explanation, and relevant misconception context. It follows a scaffolded tutoring ladder: first asking what the student tried, then pointing toward the concept, suggesting a strategy, working through one step together, and only providing heavier scaffolding after the student has struggled, adapting to and learning from the student along the way. Students can interrupt it, and we’ve begun to roll out multilingual support for Spanish, French, and a few other more niche languages that customers have asked for.

We currently use a variety of Anthropic and OpenAI models for BloomyBot. The tutor is restricted to the current lesson, redirects unrelated questions, limits conversation length, and is unavailable during mastery assessments. The language model does not choose the curriculum or decide whether a student has mastered a skill.

That separation is important. A conventionally “helpful” AI response can be a bad tutoring response: if it gives away the answer, the student completes the task but may not learn anything. Our goal is not to build a homework-answering chatbot. It is to put AI inside a structured loop of diagnosis, instruction, practice, feedback, and independent mastery.

LLMs can still be wrong, and we do not claim our constraints eliminate that. We reduce the surface area by grounding BloomyBot in authored lesson content, keeping it on topic, logging conversations, and removing it from assessments. Teachers and parents can review tutoring activity, students can report problems, and safety signals trigger human alerts and a backup audit. We also do not see Bloomy as a replacement for teachers, parents, or human tutors. A good human tutor is better. The narrower question we are testing is whether, during a bounded learning session a student would already be doing, a context-aware tutor can provide better help than static “correct/incorrect” feedback. Longer term, the question becomes more whether a student would perform better with one-on-one AI tutoring (at least in certain aspects of the curriculum) than with many-to-one instruction in a medium- or large-sized classroom.

Bloomy is now being used across several settings: traditional districts, charter schools, hybrid schools, microschools, homeschools, and families looking for additional academic support. In an early pilot at a charter school in Massachusetts serving ~150 students in grades 6 through 8, students averaged roughly 1.8 times the expected winter-to-spring NWEA MAP growth. This was an observational pilot, not a randomized study, so we treat it as an encouraging signal rather than proof that Bloomy caused the difference.

Parents and teachers can see what a student has mastered, what is in progress, and where support may be needed. We have found that adults generally do not want another generic score; they want to know which small number of skills deserve attention this week.

Bloomy makes money through family subscriptions and school licensing. ELA costs $39/month or $279/year per learner, and Writing Studio costs $19/month or $139/year. Math is scheduled to launch July 31 at the same price as ELA. Schools and microschools pay per student, with pricing varying by subject coverage, enrollment, rostering, and implementation needs.

Because children use Bloomy, we collect learning responses, progress data, and tutoring conversations. We do not sell personal information, use child data for behavioral advertising, or permit model providers to train general-purpose models on identifiable child data sent by Bloomy. We have Zero Data Retention agreements with both Anthropic and OpenAI. Parents and schools can request access, export, correction, or deletion under the applicable account or school agreement.

More background on me: after Teach For America, I taught and designed GMAT and GRE curriculum for Manhattan Prep / Kaplan, led the driver acquisition team for Lyft’s New England markets, completed an MBA at Stanford, and led AI transformation projects at McKinsey (so when models finally became good enough this past January to achieve the kinds of things I am pursuing with Bloomy, I was in the right place at the right time to begin building). Bloomy brings together the different parts of my career that I care most about: educational outcomes, learning design, building products, and getting useful technology into people’s hands.

I’d especially value feedback from parents, teachers, engineers working on child-facing AI, and people who have built tutoring, assessment, or adaptive-learning systems. Does the separation between guided AI help and independent mastery make sense? Where do you see the greatest potential with AI in education? Where are our safeguards insufficient? What evidence or product behavior would you need to trust something like this with a student?

Certainly there are many dangers and pitfalls we must beware of, too, but I believe we can really move the needle in K-12 (for the first time in a long time) if we use AI responsibly and intelligently.

81 points | 85 commentspage 2
fuddle 7 hours ago|
I think product demo walk through would be very helpful on the home page.
scoriiu 18 hours ago||
curious how the tutor handles a kid who's confidently wrong. from the description the ladder kicks in at the first sign of struggle, which sounds like it's built to prevent mistakes rather than use them. kapur's productive failure work points the other way, students who commit to a wrong approach and then get shown exactly where it breaks tend to keep the concept. the ones who got steered away before making the mistake don't.

does bloomybot ever just let a wrong approach play out and do the postmortem after? also when a struggling student gets rerouted to an easier skill, can you tell that apart in your data from one who was thirty seconds away from the useful kind of failure? the summit gate tells you they arrived. it doesn't tell you whether the help in the middle did the teaching.

alexsouthmayd 18 hours ago|
Good questions. I like that you're digging into the mechanics.

First principle: BloomyBot does not proactively engage the student unless they make 3 mistakes in a row in "Climb" (the practice portion). Then it engages them.

Otherwise, students can engage BloomyBot when they feel they need assistance.

If the student is confidently wrong and attempts to answer a question, they'll see the feedback that they're wrong, with an explanation. They can then clarify with BloomyBot. The goal here is (as you reference) to cultivate productive struggle. So we DO want the student to try their approach.

On getting rerouted to easier skills: students get 1 chance to attempt and fail a Climb. Enough questions wrong in a row (assuming they're trying) = signal that they either aren't ready to learn the skill or that they didn't pay attention to the instructional portion in Base Camp. We give them the benefit of the doubt and assume the latter. If they fail Climb a second time, they get routed to a prerequisite skill.

The Climb gates Summit through Bayesian Knowledge Tracing. Wilson et al. (2019) derived an “85% rule” from formal models of learning: training is most efficient when learners succeed at about 85% of attempts. So Bloomy uses BKT (Corbett & Anderson, 1995) to update each student’s estimated per-skill mastery after every response, and routes students to skills within their Zone of Proximal Development.

scoriiu 7 hours ago||
that's a clean answer thanks. the 85% rule for BKT routing is more principled than most. the one thing i'd still watch is wether summit mastery still holds or decays over time, since BKT can't tell "build the schema" from "learned to pass the gate". thanks for the detail.
383toast 18 hours ago||
Great idea and execution but the design language seems like general llm-generated tailwind. I think you guys are missing a huge opportunity to make the design reinforce the product positioning.
alexsouthmayd 17 hours ago|
This is interesting, can you say more?
cocoflunchy 16 hours ago|||
I think 383toast is talking about your landing page design which has very strong AI-generated design vibes (blue-green gradients, rounded rectangles with a colored border on the left...) There are a bunch of skills you can find online to improve on this if you want to keep designing with Claude, and the latest generation of models are better (Fable/GPT5.6).

Check https://github.com/jakubkrehel/skills or https://github.com/emilkowalski/skills (more around animations), maybe https://github.com/leonxlnx/taste-skill (didn't try it)

docheinestages 1 hour ago|||
I got the same vibes. I really wish YCombinator would mentor startups on design. Unfortunately, most of the landing pages in their startup directory look like raw AI designs.
alexsouthmayd 14 hours ago|||
I'll check them out, thank you for your suggestions!
paisawalla 16 hours ago|||
I spent some time researching how to teach commodity LLMs to pose geometrically correct figures and challenges, for the purpose of teaching middle school trig. I originally wanted exactly what you've described here, using AI to unlock Bloom mastery. There's a decently large surface area I covered before shelving the project. Happy to share my lessons with you
alexsouthmayd 14 hours ago||
That would be great. Please fill out your information on the below contact form, & I will follow up with you!

https://www.bloomylearning.com/#demo

dprkh 20 hours ago||
What is your approach to evaluating LLM outputs?
alexsouthmayd 20 hours ago|
A few things:

First, every BloomyBot response streams through an inline safety classification, and then an independent second-pass audit sweeps every stored message — a deterministic rule layer merged with a separate LLM classifier, taking the highest-severity result. It flags three categories (crisis, distress, inappropriate) across every language we support, and confirmed flags alert the teacher and school. We also constrain what the model is allowed to do: the tutor won't reveal answers, and it's completely absent from Summit assessments — so an LLM output never decides whether a student has mastered a skill. That comes from scored assessment performance against our 90% threshold.

Second, a nightly cron job runs across all BloomyBot interactions to flag erroneous outputs (so far, none) and safety alerts (these happen real-time anyway, but the cron job is a backup).

Third, I sample the interactions manually. I've read most interactions so far (although this will become much harder with more scale).

Finally, we are building structured evals to draw inferences across grade levels, skills, common misconceptions, etc. Ideally we will be able to identify the optimal level of scaffolding to help students achieve mastery, but that will take more data and time.

KomoD 19 hours ago||
Was this comment generated? Your other comments use "--" instead of an em dash... or were all of them generated, but you forgot to replace them with "--" in this one?

See: https://news.ycombinator.com/newsguidelines.html

> Don't post generated text or AI-edited text. HN is for conversation between humans.

alexsouthmayd 18 hours ago||
I've been extremely inconsistent in my dashes today as I flip between different devices :)
JimsonYang 15 hours ago||
Tell us about the test scores increased? Did you find similar results on the PSAT?

If your metrics are good, increasing test scores is the thing thats 100% going yo get schools on board

alexsouthmayd 15 hours ago|
We ran a pilot with roughly 150 students in grades 6–8. Students who used Bloomy for one hour per week averaged 1.8x their expected winter-to-spring growth on NWEA MAP.

Our team was understandably energized by these results, and we plan to run several more pilots this fall to see whether we can produce similar gains across other student populations and assessments, including the PSAT.

ChaitanyaSai 7 hours ago||
Congratulations on the launch!

How do you solve for "meaning?" Is there some implicit expectation that kids arrive with motivation to discover meaning, or some extrinsic rewards?

As AI essentially commoditizes the mechanical aspects of learning, this is the question we find ourselves asking.

I would like to share our journey running a microschool (where our kids go, along with 40 others now) and how we use AI and what we think about its role.

Some useful context, because this really has informed our approach. I am an engineer turned neuroscientist and the co-author of a popular nonfiction book on the mind (and I share this here because the hard effortful self-driven work of crafting this book taught me more about the mind than anything else in my PhD or later). This work, done during the pandemic when learning was coming online, was what pushed us into setting up the school and gave us the courage to work on it from first principles and not rely on any off-the-shelf alternative pedagogy (montessori, waldorf etc). We looked at (and continue to work on) the full-stack of philosophy, pedagogy, process, practice. So the "what should they learn" is also met with "why should they learn this" and also "how should they be learning this"

The *single biggest* learning for us, which we are now able to articulate clearly, is that schools are set up to fail because there is a well-intentioned but misguided focus on measurement (what are they learning). This gravitational pull results in a focus on mechanics (the most easily measurable thing; long division, periodic tables). This results in a narrow focus on concepts (what David Perkins terms elementitis). Most importantly, what gets left out is meaning. Why should I care about this? With a well-intentioned curriculum and an administration pipette we basically leach out agency and meaning.

So we try to solve for meaning. Our biggest worry with AI is that it focuses entirely on mechanics, with very little meaning. Adults and kids are learning to discount AI-content as automated and inauthentic. We derive meaning from connection. AI can help with the mechanics, but only when meaning has been established. Without this clear-eyed understanding and buy-in we basically have chromebooks all over again, which flattened learning to 2D screens and accomplished nothing (if you look at literacy numeracy scores)

Chatbots are great if you start with meaning and motivation. I already care about the why, so I will socratically find my way to the how and what. But if we do not care about it, which really is the biggest malaise (why should a child who has not yet explored the world or literature they like care about foreshadowing or plot mountains?) Sure, the AI could make it easier, but the kids still need to care?

Wrote about our meaning > motivation > mechanics > measurement revelation and the usual unfortunate inversion here https://blog.comini.in/p/schooling-has-a-meaning-crisis-para...

We need many more people approaching education with ideas and experiments, so thank you and good luck!

verdverm 19 hours ago||
Childhood psychologists are warning about giving Ai to children, very similar to social media and generally screen time.

How does this factor into your business?

alexsouthmayd 18 hours ago|
I just posted something pretty relevant to this in a different comment. Totally agree with the dangers. 2 important points:

1. Not all AI is the same. I see 2 MECE categories in education: AI that does all the thinking/execution for you (the outsourced brain), and AI that is designed to fulfill specific coaching/tutoring roles. If we design AI to ask great questions and find the Socratic thread with students, we can actually make students think harder and learn faster.

2. Social media is full of cheap dopamine. See my comment about 'effortful dopamine' for my perspective on this.

hasteg 12 hours ago||
I agree that using AI as a "tutor" to help teach yourself things is very useful and works great, I've been doing that myself quite a bit. How do you stop students from being able to just use it as a second brain? I assume there's some sort of guardrails you have so it won't just give the answer? How do you ensure that there's an adequate amount of "struggle" that the kids are going through before just explaining the answer? I feel that that would be the challenging piece of the puzzle.
Onavo 18 hours ago||
Will ChatGPT dream of Bloom's 2 Sigma problem?

https://en.wikipedia.org/wiki/Bloom%27s_2_sigma_problem

2arrs2ells 17 hours ago|
Check out https://www.modernbloom.org/
cynicalpeace 19 hours ago||
The fastest, most surefire way to nuke your child's brain is to give them a screen.

There is certainly room for software to design a curriculum for the parent or teacher to use. We have tried (and failed) to find such a thing for our homeschool curriculum.

But giving the kid a screen? If you're even a midge honest with yourself, a screen will de-educate your child, leading to the opposite of the intended consequence.

alexsouthmayd 18 hours ago||
I empathize with the screen time concerns - the reality is most kids in classrooms are already on screens, which are doing very little to move educational outcomes (from what I can tell based on the NAEP evidence).

And then you also have kids at home who are on TikTok or Instagram reels - combining screen time with easy dopamine.

Some kids using Bloomy decide to use it at home in lieu of social media time. I'd take that as a win. Cheap dopamine erodes focus and mental resilience. Bloomy focuses on ‘effortful dopamine.' We structure the experience so that students generate reward by conquering academic challenges, training the brain to find satisfaction in effort, patience, and mastery rather than passive consumption.

I'd be curious to see data that can isolate the relationship between educational outcomes and small bursts of high-quality instruction delivered via tech. That's one longer-term outcome we're trying to demonstrate. So far our efficacy results (still early pilots, but correlative) appear to be incrementally positive.

cynicalpeace 17 hours ago||
Regardless of the content on the screen, the screen time is bad for kids.

Even desiring pixel-represented "data" for this fact that is obviously observable irl is itself perhaps a result of excessive screen-time, leading to spreadsheet brain, but I can gratify you with these studies: [1], [2], [3], [4], [5]

Of course, no study will exactly disprove the claim that there is some possible content that is a net positive for kids, akin to how no study can prove that unicorns don't exist. But this is exactly the kind of brain-melt, culturally destructive kind of thinking you could expect for demanding "data" for every obvious fact.

Screen time is simply bad for kids. Don't give your kids a screen. Give them a ball, a stick, a book, etc

[1] https://jamanetwork.com/journals/jamapediatrics/fullarticle/... [2] https://jamanetwork.com/journals/jamanetworkopen/fullarticle... [3] https://red.library.usd.edu/cgi/viewcontent.cgi?article=1002... [4] https://jamanetwork.com/journals/jamapediatrics/fullarticle/... [5] https://pubmed.ncbi.nlm.nih.gov/32202633/

alexsouthmayd 17 hours ago||
Thanks! I’ll have a read. Appreciate your taking the time to source and share these.
tekne 18 hours ago||
Eh.

On one hand -- phones are evil, and the world is no longer 2004.

On the other hand, I would not be the same person if I didn't get that laptop.

motoxpro 20 hours ago|
Happy that this is being tried. I find it weird, sad, unfortunate, etc. that everyone in tech thinks about scientific discovery and drug discovery as AIs boon to society over education.

Every quality of life metric (life expectancy, income, etc) goes up with better education. I guess it’s because most people in tech grew up in neighborhoods with nice schools and went to college so they don’t think about it.

Anyway, great luck.

alexsouthmayd 20 hours ago|
Thanks! I think people are rightfully skeptical about EdTech and AI -- esp. with kids. But we also need to try to innovate in this space, and I believe (from my experience as a teacher as well as my experience seeing students learn on Bloomy) that there is great potential here.
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