How to start a Locked Assignment Windows Inside the LMS business: plan and growth
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.
An owner can start “Locked Assignment Windows Inside the LMS” from a complaint people already posted. The offer, in one line: Verifiable in-class 'closed windows' for assignments, built into Canvas, instead of hacky access codes. It is for teachers and schools. Charge a B2B subscription, and test a price between $50 and $199 a month. Begin in the United States. Buyers already talk about this in r/Teachers. One thread gathered 855 votes and 136 replies across Sep 14, 2026 – Oct 14, 2026. Use that room to meet the first twenty buyers. Do not export it, and do not republish the posts. The idea, the evidence, and the market estimate on this page are free to read. Two paid prompts finish the job: one drafts the offer, the price, and a ninety-day calendar; the other drafts a month of conversations and proof. One credit unlocks both. A software specification is not on this site. When the company is the product itself, a single link further down opens the founder library.
Why does your assignment have an access code onr/Teachers · Sep 14, 2026 – Oct 14, 2026 · 855 votes · 136 replies · Open the thread
Who would pay
Teachers and schools. Start in the United States, and charge a B2B subscription, testing a price between $50 and $199 a month.
The thread above is the public complaint this business can learn from. Verbatim quotes are not invented. Further sources, when a later report adds them, stay with the evidence.
What buyers use today
- Canvas access codes
- Respondus LockDown Browser
- GoGuardian
The offer, in our words
An assignment layer that creates a verifiable closed completion window (local timer, tab/device control) inside existing LMSs instead of homemade access codes.
Score 3.75, Hot. Pain, willingness to pay, demand, and the gap in current options drive it. We are not scoring how fast you can code.
Market size
An estimate, built from the bottom up: real customer counts × a realistic price. It shows the size of the prize, not a forecast.
TAM Total addressable
$66M a year
1.1M teachers · 30% of US public school teachers
SAM Serviceable
$19.8M a year
330,000 teachers · schools on the LMSs it supports
SOM Obtainable in 3 years
$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 confidence · estimated Oct 2026
How 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 is customers with the problem × revenue per customer. SAM is the part a new business can reach. SOM is a cautious three-year share of SAM. The bars use a log scale. A share marked “assume” is our judgment, not a measurement.
Source: NCES, Characteristics of Public School Teachers (2020–21)
The business-plan prompt
The offer, the price, and a ninety-day calendar, written for an agent. 1 credit unlocks both prompts for this idea: this plan and the growth playbook below.
# Business plan prompt: Locked Assignment Windows Inside the LMS You are writing a practical plan for one owner who will sell this as a business. Do not write a software specification, a venture memo, or a feature list. Use short sentences. Where a number is unknown, give a range and say what to measure. ## The business Working name: Locked Assignment Windows Inside the LMS What the customer gets: Verifiable in-class 'closed windows' for assignments, built into Canvas, instead of hacky access codes. Who pays: Teachers and schools
Locked · the first lines are above
Unlock both prompts for this idea · 1 credit ($9.99)
One credit opens the business plan and the growth playbook together, for good. Credits work on both businessideastobuild.com and realstartupideas.com.
Sign in once with your Real Startup Ideas account; the same credits work on both sites.
The growth playbook
Thirty weekdays of conversations and proof. Not an ad plan. Included with the plan above, on the same credit.
# Growth prompt: Locked Assignment Windows Inside the LMS You are planning thirty days of distribution for a business that already has an offer. The offer: Verifiable in-class 'closed windows' for assignments, built into Canvas, instead of hacky access codes. The buyer: teachers and schools. Price band: between $50 and $199 a month. Do not propose ads, a viral loop, or a rebrand. Propose conversations, proof, and a repeatable weekly rhythm. ## Starting point A public thread in r/Teachers drew 855 votes and 136 replies. The pain, in the owner's words: 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.
Locked · the first lines are above
Unlock both prompts for this idea · 1 credit ($9.99)
One credit opens the business plan and the growth playbook together, for good. Credits work on both businessideastobuild.com and realstartupideas.com.
Sign in once with your Real Startup Ideas account; the same credits work on both sites.
Questions
How much money do I need to start?
Enough to talk to buyers and deliver the offer once. A service version can start with a written process and a way to take payment. A software version is a larger bet and is not required to test the price. The band to test is $50–199 a month.
How should I price it?
Test a price between $50 and $199 a month, charged as a B2B subscription. Raise it after three paid pilots, not before the first conversation.
Where do the first customers come from?
r/Teachers is the clue. A related thread gathered 855 votes and 136 replies. Show up there, follow the room's rules, and ask for conversations. Do not scrape it.
Do I need to write code?
No. The prompts on this page draft a plan and a month of growth. Code is a later choice. The founder site linked once below is where the build document lives, if you want it.
The founder library has the software specification and a done-for-you build. Read the agent PRD
A two-week build starts at $10,000 on that site, after a $1,000 scoping fee.
Plans and growth playbooks
One credit opens both prompts for this business.
The idea, the evidence, and the market estimate stay free. The business plan and the thirty-day growth playbook for Locked Assignment Windows Inside the LMS cost one credit, together, and stay unlocked.
Credits work on both businessideastobuild.com and realstartupideas.com. Sign in once with your Real Startup Ideas account; it is the same wallet.