Kastr vs ClassDojo

Six rows above go to ClassDojo, and four of those — single sign-on, photo and file sharing, push notifications, and having customers at all — are things a district notices in the first fortnight. The consumer subscriptions and the unpriced district add-ons are both from ClassDojo's own public pages, read on 4 August 2026.

Where ClassDojo is genuinely stronger

We should get the honest part out of the way before the argument, because the argument is not about capability.

• Teacher adoption. ClassDojo did not win K-8 through district sales; teachers adopted it and then told each other. Nothing we ship in the next three years will produce that. If your evaluation criterion is "will staff actually use it", they have the strongest evidence in the category.
• Single sign-on. Google, Microsoft, SAML and ClassLink. Our only authentication today is a magic link. For a district standardised on Google Workspace or Entra ID that is a real, daily, operational difference.
• Photos, video and file sharing. Core to what teachers do with it, and something we have not built at all.
• Native mobile apps with push notifications. Ours is a web app and push is not wired up.
• Real district case studies and reference calls. We have none. We are recruiting design partners, which is the honest answer in August 2026 and not a satisfying one.
• Free is genuinely free to your budget. Not a trick, not a trial, not a bait tier. The district line item is zero and stays zero.

If those six things are what your evaluation weights, ClassDojo wins it, and we would rather you read that here than discover it in month four of an implementation.

Free is real. The cost moved rather than disappeared.

ClassDojo's district product is free because families buy consumer subscriptions inside the same app. Dojo Sparks is published at $9.99 a month or $64.99 a year. ClassDojo Plus, the older parent subscription, carries no published price at all — their marketing pages contain no currency figure and the price appears only in-app. ClassDojo has said roughly one family in twenty converts. ClassDojo's own district-facing page describes paid add-ons "for the 1 in 10 that need extra support" without naming a price for any of them. Both of those facts come from their own public pages; neither is a leak or an accusation.

The arithmetic is worth putting on a slide before a board approves anything. Take a district of 6,000 students, call it 4,200 households. At the stated 5% conversion on the published $9.99 monthly rate, roughly 210 households pay about $120 a year, and something in the region of $25,000 a year leaves your community for a vendor. The same district on our rate pays $19,500 from the district budget and families are charged nothing.

Two caveats we will state ourselves, because a comparison page that omits them is not credible. Conversion rates vary by district and we do not know yours. And nobody is compelled to subscribe — families who decline still get the core product.

What is left after both caveats is the distributional question, and it is the one that actually matters. The families most likely to pay $120 a year for extras inside a school communication app are not evenly distributed across your enrolment. Whether a district should route a discretionary spend of that shape through a tool its schools require families to install is a values judgement belonging to a board, not a technical judgement belonging to a CTO. Reasonable people land in different places on it. We landed somewhere specific and wrote it into the contract at §9.4: Kastr will not market or sell to district families, will not derive revenue from family-facing subscriptions, fees or transaction processing, ever. It is a clause, not a value we published on an about page.

Free also removes the paperwork that protects you

This is the part that tends to surprise people who have only evaluated paid vendors. A great deal of what a district relies on in a supplier relationship is not product; it is contract. When there is no invoice, there is often no negotiated master agreement either, and the terms are whatever the click-through says on the day.

Three specific consequences worth checking before your board approves anything, whichever vendor you pick:

1. Export. Ask what you can take out, in what format, covering which record classes, and whether the right is time-limited. Ours is a contract term at §7.1 — export everything, any time, machine-readable, no notice and no fee. Being precise about today: self-serve export tooling ships with the May 2027 release, so until then we run it for you on request, same day. The right is contractual now; the button is not.
2. Change of control. This category consolidates relentlessly — ParentSquare acquired Remind in 2023, PowerSchool acquired SchoolMessenger. Our §11.2 lets you terminate within 90 days of an acquisition or a material change to data terms, with export and a prorated refund. Ask any vendor whether you get the same.
3. Price. Free is not a price commitment; it is a current state. Ours is fixed for 36 months at §3.2, then capped at the lesser of CPI-U or 5%.

One small observation about doing this homework: ClassDojo publishes no comparison pages, no alternatives pages and no glossary, and covers exactly one of fifty states. Neither does most of this category. Whichever way you go, nobody selling to you is going to hand you a fair map of the alternatives, which is a reasonable argument for building your own shortlist before you take the first call.

Where the district-grade gap actually shows

ClassDojo is a classroom product with a district console attached. We are a district product with no classroom ambitions. That shows up in specific, unglamorous places.

One person, many roles

A teacher at the middle school who is also a guardian at the elementary school is one human being. We store one person record with effective-dated role rows attached, so she is genuinely both, and messages resolve once rather than twice. Classroom-rooted products tend to scope identity to the classroom, and the duplicate-account complaint that follows is the single most common family-facing annoyance in this category.

The roster failure that takes a district offline

A truncated CSV or a half-finished export can withdraw most of your active records in one sync, and the symptom is that thousands of families silently stop receiving anything. Our sync aborts if it would withdraw more than half your active records, and tells you why. It is a guardrail nobody markets because it is only visible on the day it saves you.

Your data is scriptable

We ship 28 documented REST endpoints, an MIT-licensed CLI, an MCP server, and outbound webhooks signed HMAC-SHA256 over the raw body with a DNS-resolving SSRF guard, exponential backoff and automatic endpoint disable. Neither ClassDojo nor most of this category publishes a district-facing API at all. If your team wants to script a bulk operation at 11pm on a Sunday, that is the difference.

You see the bill before you send

The composer shows a live per-channel cost and reach estimate as you tick channels, renders your draft in up to five languages before it goes anywhere, and will send only to you with a [TEST] prefix. None of that is clever. It is just the set of things that stop a 40,000-recipient mistake, and it is odd how rarely it is present.

When Kastr is the wrong answer here

Do not shortlist us against ClassDojo if any of these is true:

• You are replacing behaviour points, portfolios or classroom culture. We do not build that category and will not. Look at ClassDojo versus Seesaw instead; that comparison has no Kastr column and is more useful to you.
• Your budget for family communication is genuinely zero. Then free wins, and the honest alternatives are ClassDojo or TalkingPoints, which is a non-profit and charges nobody.
• SSO, attachments or push are non-negotiable. All three are gaps we intend to close and none of them is closed today.
• You need a completed SOC 2 report to clear your own security review. We have not been audited. Our trust page states what is and is not true, with dates on it.

If what you actually need is official district communication — the closure notice, the attendance letter, the message that has to reach every household in the language it reads — then the question is which vendor you want holding that, and on what terms. That is the conversation we are built for.

Questions people actually ask

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