UserAuthGuard vs Blocksi
Blocksi sells web filtering, classroom management and student safety tools. UserAuthGuard decides who may sign in to each Chromebook and keeps the record of who has it. Different jobs, at different layers. Here is how to tell them apart.
The Short Version
Blocksi is a content filtering, classroom management and student safety product for K-12. It works on the browsing session: what a signed-in student can reach, what a teacher can see during a lesson, what gets flagged. For what Blocksi does today, read Blocksi's own site. It will be more current than anything we could write here.
UserAuthGuard works one layer earlier, at the sign-in screen. Each Chromebook gets its own organizational unit in Google Workspace, with a sign-in restriction naming the one student allowed to use it. Google refuses anyone else before the desktop loads. Behind that sits the record a filter is not built to keep: who has which device, its assignment history, check-in and check-out, repairs, and end-of-year collection.
You will not find a list of what Blocksi cannot do on this page. Vendors ship features, and a checklist of someone else's gaps is wrong the day after it is published. Instead, this page describes what a content filter is for and what device assignment enforcement is for, so you can place any product, Blocksi included, yourself.
Two Different Jobs
One works on the browsing session after a student signs in. The other decides who gets to sign in at all.
Filtering, Classroom View, Safety Alerts
"What is this student doing in the browser?"
- Blocks or allows sites by category and list
- Shows a teacher the screens in the room during a lesson
- Flags searches and content that suggest a student is at risk
- Applies rules to whoever is signed in, by user or group
- Runs through an extension or a network layer that has to be present and running
Device Assignment Enforcement
"Who is allowed to sign in to this Chromebook, and who has it?"
- One organizational unit per device, with a sign-in restriction naming one student
- Google refuses anyone else at the sign-in screen; nothing is installed on the device for this
- Assignment record with history: who has it, who had it, when
- Check-in and check-out, loaners, end-of-year collection by scan
- Repair queue with parts and technician assignment, in the same device record
- Optional classroom and safety extension, if you want one vendor for both layers
Side By Side, By Question
The questions a technology office actually asks, and which layer answers each one. Place Blocksi in the filter column yourself.
| The question | UserAuthGuard | A content filter |
|---|---|---|
| Access | ||
| Who can sign in to this Chromebook? | The one student named on the device's unit.Google refuses everyone else at the sign-in screen | Not its job.A filter starts work after sign-in, on whoever signed in |
| A student picks up a classmate's device. What happens? | Sign-in is refused.The device stays tied to its assigned student | The session gets that student's rules.Whether the swap is noticed depends on your records |
| The record | ||
| Who has this serial number, and who had it before? | The assignment record, with history and timestamps. | Not what a filter is for. |
| Is this device checked in, out on loan, or in repair? | Check-in, check-out, loaners and a repair queue.Parts and technician on the same record | Not what a filter is for. |
| How many came back in June, and from whom? | Scan-in collection, reconciled by student. | Not what a filter is for. |
| The browsing session | ||
| What can the student reach, and what is on the screen now? | Optional.A classroom and safety extension is included if you want it; the sign-in lock does not depend on it | This is the job.Site filtering, classroom screen view, safety alerts |
| What enforcement depends on | ||
| What has to be on the device for it to hold? | Nothing.The lock is a Google Workspace policy on the device's unit | The filter itself.An extension or network layer that must be present and running |
How the Lock Works
Four steps, all of them inside Google Workspace. This is what OU-Lock is.
One unit per device
Each Chromebook is moved into its own organizational unit in Google Workspace. The unit becomes the device's identity in your domain.
One name on the unit
A sign-in restriction on that unit names the one student allowed to sign in. Reassign the device in UserAuthGuard and the name on the unit changes with it.
Google does the refusing
Anyone else who tries is turned away at the sign-in screen by Google itself. There is nothing on the device to uninstall for this to hold.
The record rides along
Assignment history, check-in and check-out, repairs and collection all hang off the same device record, so "who has this?" is a lookup, not an investigation.
Frequently Asked Questions
Can I run UserAuthGuard alongside Blocksi?
Yes. UserAuthGuard enforces at the Google sign-in screen. A content filter works on the browsing session after sign-in. The two layers do not conflict, and neither needs to know the other is there. A device that stays in its own unit also keeps whatever unit-level policies you have applied there, including filtering policies.
Does UserAuthGuard replace Blocksi?
That depends on what you bought Blocksi for. If you bought it hoping to know who has which Chromebook and to keep students on their own device, that is UserAuthGuard's core job and not what a content filter is built for. If you use it for filtering, classroom screen view and safety alerts, UserAuthGuard includes an optional classroom and safety extension, and whether it covers what you use today is for your own evaluation. We will not make that call for you with a checklist of Blocksi's gaps.
What is OU-Lock?
Each Chromebook gets its own organizational unit in Google Workspace, and that unit carries a sign-in restriction naming the one student allowed to use the device. Google enforces it at the sign-in screen, so anyone else is refused before the desktop loads. Reassigning the device updates the restriction. Nothing is installed on the device to make this work.
What does Blocksi do?
Blocksi describes itself as web filtering, classroom management and student safety for K-12 schools. For the current feature set and pricing, go to blocksi.net. We describe Blocksi only by the category it sells in, because Blocksi's own site is the right source for anything more specific.
Why doesn't this page list what Blocksi can't do?
Because we cannot keep such a list true. Vendors ship features without telling competitors, and a comparison table full of crosses is a snapshot that ages badly. We would rather tell you what a content filter is for, what device assignment enforcement is for, and let you place the products. If you want to know what Blocksi does, ask Blocksi. If you want to know what UserAuthGuard does, start the free plan and look at your own fleet.
Is UserAuthGuard really free?
Yes. The free plan is read-only visibility of your whole fleet: every device, user and organizational unit, assignment gaps, and fleet reporting. No device cap, no credit card, no trial clock. Enforcement (OU-Lock, bulk operations, and the classroom and safety extension) is paid, with published pricing and no multi-year commitment required.
About the claims on this page
Everything said here about UserAuthGuard describes our own product. Blocksi is described only by the category it sells in, web filtering, classroom management and student safety, which is how Blocksi presents itself publicly as of November 1, 2026. We make no claim about what Blocksi can or cannot do, and we link to Blocksi's own site for anything current. If you work at Blocksi and believe we have placed you wrongly, tell us and we will correct it.
- Blocksi, company site: https://blocksi.net/
Know who has every Chromebook
Keep your filter. Add the layer underneath it. Free to find every gap, paid to enforce assignment, with published pricing.