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Fortresses
Hard to copy, hard to dislodge, and they grow without growing costs. All three at once is rare.
12 teardownsEvery teardownEasy to copy. Won anyway.Built on rented landNumbers straight from a filingDoesn't scale. On purpose.Still here after 15 yearsOne-time money
AppSumo
Marketplace
Sells software lifetime deals to a 1.5M-buyer list.
$80M
Stated · 2023 revenue
One-time cash, no recurring revenue.
★ The edge: The product is distribution, not deals: a 1.5M-buyer list makers hand 70-80% of a Select deal to reach.
Open → full teardown→
BiggerPockets
Community
Real estate's town square — a free forum, 3M+ members.
$7M
Stated · 2016 rev · last public
⚠ Need cyclical
under 1% pay
under 1% pay
★ The edge: Dorkin kept the forum free for years before charging — trust and UGC compounded into a moat rivals can't buy.
Open → full teardown→
BuiltWith
Data
Fingerprints a site's tech stack — then sells the reverse.
$14M/yr
Estimate · annual revenue (est.)
Lookup is free · lead-gen cut first
★ The edge: the lookup is free — the real moat is 18 yrs of crawl history nobody can back-fill.
Open → full teardown→
Chrono24
Marketplace
Global marketplace for pre-owned luxury watches.
€103.2M
Filed · FY2021 group accounts
Dealers could bypass; GMV swings with prices.
★ The edge: Free built-in escrow lets strangers wire $50K for a used watch across 150 countries without fear of fakes.
Open → full teardown→
Envato
Marketplace
The bootstrapped stock-asset market that paid out $1.3B
$245M
Filed · all-cash exit, 2024
Its subscription now cannibalizes its authors
★ The edge: Launched the marketplace, then built Tuts+ — the web's biggest design-tutorial network — to feed it buyers.
Open → full teardown→
Foundry VTT
Marketplace
The virtual tabletop you buy once, not rent.
$3-10M/yr
Estimate · est.; undisclosed
Owners buy once - little recurring revenue.
★ The edge: Buy-once $50 license in a subscription world; users self-host, so Foundry's server costs stay near zero.
Open → full teardown→
Nomad List
Community
Find the best city to live & work as a nomad — by data.
$38K/mo
Stated · $0 VC · solo
⚠ Need·Time soft
niche + travel churn
niche + travel churn
★ The edge: the moat isn't the data — it's 11 yrs of user-filled data + community + his public brand (@levelsio), all solo.
Open → full teardown→
OnlineJobs.ph
Marketplace
Flat $69/mo to hire from 2M Filipino workers.
$10M+/yr
Stated · founder-stated, 2022
Employers cancel right after they hire.
★ The edge: 15 years of free how-to-hire content sends every 'hire a Filipino VA' search to the niche's deepest worker pool.
Open → full teardown→
Sansan
Data
Japan runs on business cards. Sansan digitized them.
$280M
Filed · ARR, May 2025 (¥41.5B)
The card ritual fades as work goes remote.
★ The edge: Rivals trust OCR; Sansan runs every card through human operators too — 99.9% accuracy is the data moat.
Open → full teardown→
Shodan
Data
Google indexes web pages. Shodan indexes devices.
$1M+/yr
Estimate · Bootstrapped, no VC · est
Key-person lean; Censys cloned it with VC.
★ The edge: A 15-year, continuously-crawled index of every service on the public internet — a dataset newcomers can't back-fill.
Open → full teardown→
Vinted
Marketplace
Europe's clothes resale. Buyers pay, sellers don't.
€1.1B
Stated · $1.2B · 2025 revenue, +38% YoY
Most revenue is one fee buyers love to hate.
★ The edge: Taxes buyers, not sellers. Free listing grows supply, supply grows demand — liquidity fee-charging rivals can't match.
Open → full teardown→
World Anvil
SaaS
Build your fictional world — a wiki for writers & GMs.
$1M+
Estimate · ARR est · undisclosed
⚠ Need niche
small TAM · free-heavy
small TAM · free-heavy
★ The edge: anyone can clone a wiki — the lock-in is years of your interlinked lore living inside it, plus a 3M community.
Open → full teardown→