Nexus vs Flint

[ SUMMARY ]

The short version

Flint and Nexus are the two products closest to the same idea: a school-wide AI that students use under school rules. Flint is established in independent schools, with low published prices and always-on self-harm alerts. Nexus lets the school choose the models for each class and lets students compare them, with each class's learning mode locked.

What each product is

Flint. A K-12 AI platform. Teachers build AI activities, and students get the Sparky tutor plus a general chat that coaches instead of writing for them. Schools can turn chat off by grade. Flint reported more than 800,000 users in September 2026 and raised a $15M Series A in November 2025.

Nexus. The AI your school can approve, built on Onyx's open-source platform. Students choose a class and ask for help on whatever they are working on; the class's learning mode (Hints, Guided, or Full answer with critique) applies, and students cannot change it.

Models and model choice

Flint uses Anthropic and OpenAI models and picks them for the school; its paid plans get a stronger model. Nexus lets your school approve models for each class from its reviewed list, and students can compare answers from two or three models the school allows.

Model choice is rare in K-12, and no study shows that it helps learning. In a two-year trial in 18 middle schools, the median student messaged an AI tutor on a third of practice days. How students use AI, not which model they get, limited the results. We present comparison as a way to practice judging AI answers, not as a learning gain.

Visibility and privacy

Flint's school admins can search every chat, and class editors can read class chats. Nexus shows staff less: class chats only, with notice to students, and a record of who opened each class conversation. Personal chats are not shown to teachers.

That difference cuts both ways. A school that wants staff to see everything a student types will prefer Flint's model. A school that worries about students holding back their questions may prefer Nexus's two zones.

Safety

Flint's self-harm alerts are always on and cannot be turned off. Nexus is a study assistant, not a counselor. Before any student uses Nexus at your school, we set up a safety route with you.

Price

Flint is free up to 80 users (students and staff), then $3,000 a year for up to 150 users, $4,000 for 250 and $6,500 for 500. See Nexus pricing, and use the cost calculator to set your own limits.

When Flint may be the better fit

• You want a low published price and a free tier for a small first group.
• You want self-harm alerts that are always on from day one.
• You want teachers to build AI activities as well as offer open chat.
• You serve students under 13. Nexus is for 13 and older.

When Nexus may be the better fit

• You want the school to choose models per class, and students to compare answers from two or three.
• You want a learning mode on every class chat that students cannot change.
• You want personal chats kept out of teacher view and every staff read logged.
• You run Canvas or Blackbaud. Nexus has built connections for both: Canvas ships with the next release, and Blackbaud has not yet run against a real school account. See integrations.