Startup idea: Locked Assignment Windows Inside the LMS
Teachers put access codes on Canvas assignments to stop AI/Google cheating, then angry parents demand the codes be sent home. The system gets gamed from both sides.
Get the PRD prompt, $9.99 Market: $198K in 3 years
r/Teachers · Sep 14, 2026 – Oct 14, 2026 · 855 upvotes
Why does your assignment have an access code on
Read the thread · 136 comments
Locked Assignment Windows Inside the LMS is a startup idea for teachers and schools. Teachers put access codes on Canvas assignments to stop AI/Google cheating, then angry parents demand the codes be sent home. The system gets gamed from both sides. A thread in r/Teachers drew 855 upvotes and 136 comments between Sep 14, 2026 – Oct 14, 2026. People get by with Canvas access codes, Respondus LockDown Browser, and GoGuardian, and that still leaves this job open. Hotness is 3.75, Hot. Strong pain. Some willingness to pay. The thread drew 855 upvotes and 136 comments. Gaps in existing tools. Needs integrations or data deals. A first version is a hard build, about 5+ weeks, priced between $50 and $199 a month and charged as a B2B subscription. The pain, the source, the alternatives, the scope notes, and the questions on this page are free to read and free to build from. The agent starter prompt is the paid part. The first slice is on the page. One credit unlocks the rest, to paste into a coding agent, download as Markdown, or send as a private link.
Who has it
Teachers and schools.
- Teachers
- Schools
- B2B
- United States
- r/Teachers
What people use now
3 options, and the gap between them.
Canvas access codes
Respondus LockDown Browser
GoGuardian
Real gaps in the existing tools.
Locked Assignment Windows Inside the LMS is built for the part these leave undone.
A way through
An assignment layer that creates a verifiable closed completion window (local timer, tab/device control) inside existing LMSs instead of homemade access codes.
MVP scope
The first version, in 5 weeks.
- 00 Goal
The one job
Verifiable in-class 'closed windows' for assignments, built into Canvas, instead of hacky access codes.
- 01 Weeks 1–2
The core
Create a verifiable closed completion window (local timer, tab/device control) inside existing LMSs instead of homemade access codes.
- 02 Weeks 3–5
How it ships
As a browser extension that works on the pages people already use. AI helps, but the core job works without it.
- — Not in v1
Left out on purpose
Replacing Canvas access codes. Version one does the one job above and stops there.
How it could charge
The business model, at a glance.
- Model
- B2B SaaS
- Price
- $50–199 a month
- Buyer
- CompaniesA business with a budget pays
- Region
- United States
Hotness
Why it scores 3.75.
Strong pain. Some willingness to pay. The thread drew 855 upvotes and 136 comments. Gaps in existing tools. Needs integrations or data deals.
855 upvotes 136 comments r/Teachers Sep 14, 2026 – Oct 14, 2026 verified Oct 14, 2026 Thread ↗
Weights: pain 25%, willingness to pay 20%, demand 20%, gap 15%, ease 10%, recency 10%. Recency is recomputed every build. The source report’s 1–10 score is not shown.
Market size · estimate
How big this could get
A bottom-up estimate for Locked Assignment Windows Inside the LMS: real customer counts × a realistic price. Not a forecast.
$66M a year
1.1M teachers · 30% of US public school teachers
$19.8M a year
330,000 teachers · schools on the LMSs it supports
$198K a year
3,300 teachers · 1% of the reachable segment in three years
What that means
3,300 teachers at $5/mo = $198K ARR
Medium confidenceHow we estimated this
- Base: 3,760,000 US public school teachers.
- Has the problem: 30% (assume 30% give timed LMS assessments).
- Revenue per teacher: $60 per year ($60 per teacher a year, sold to schools).
- Reachable: 30% (schools on the LMSs it supports).
- Three-year capture: 1% of the reachable segment.
TAM = customers with the problem × revenue per customer. SAM = the part an early product can reach. SOM = a conservative three-year share of SAM. Bars use a log scale. Shares marked “assume” are our judgment, not measured.
Source: NCES, Characteristics of Public School Teachers (2020–21)
Take it to a build
Build Locked Assignment Windows Inside the LMS with an agent, or with us.
Agent starter prompt
$9.99 / 1 credit
A full PRD written for a coding agent: scope, data model, screens, edge cases, and the first week of tasks for this idea.
- Copy it straight into Claude Code, Cursor, or Codex.
- Download it as a .md file you keep.
- Send your bot a private link that refreshes every seven days.
# Agent starter prompt: Locked Assignment Windows Inside the LMS You are a senior product engineer. Build only the product described in this document. If a detail is missing, choose the smallest option and write it down in the README. Do not invent a second product, a marketplace of marketplaces, or a growth hack. ## Product Name: Locked Assignment Windows Inside the LMS One line: Verifiable in-class 'closed windows' for assignments, built into Canvas, instead of hacky access codes. Shape: Browser extension AI stance: AI-assisted Region for v1: United States Hotness (context only, not a requirement): 3.75 (hot). Strong pain; some willingness to pay; thread engagement 855▲/136💬 (demand 5/5); gaps in existing tools; needs integrations or data deals. ## Problem Teachers put access codes on Canvas assignments to stop AI/Google cheating, then angry parents demand the codes be sent home. The system gets gamed from both sides. Who feels it: Teachers and schools.
The first slice is above. The rest unlocks for 1 credit and is never in this page’s HTML.
Credits work on both sites. On Business Ideas to Build the same credit unlocks the business plan and growth playbook for Locked Assignment Windows Inside the LMS.
Or we build it
Your first version, shipped by our team.
A working product in your repo, built from this PRD. You own the code.
$1,000 scoping fee, credited toward the build.
Equity instead of cash is an application, not a checkout →Questions
Is this idea already taken?
People already use Canvas access codes, Respondus LockDown Browser, GoGuardian. Those options do not do the job in the solution above. The idea is free to build. Nothing here is an exclusive claim.
How hard is a first version?
Hard. A tight MVP is about 5 weeks (5+ weeks), assuming the regulated or partner-gated parts are stubbed. The paid prompt turns that into tasks.
Who would pay, and how?
The audience is teachers and schools. Charge a B2B subscription, and test a price between $50 and $199 a month. Willingness to pay is one input to Hotness, not a promise that someone will buy.
Can I use the evidence?
Yes. Build the product. The thread title is a short excerpt with a link, not a quote we are putting in someone's mouth. Exact post dates and verbatim lines are added only after a manual check. Ideas are suggestions, not medical, legal, or financial advice.
The sister site has the plan and the first month of distribution. Your credits work there too. Draft the business plan