Source directory: four grades of trust

Finding ideas and finding revenue are not the same search, and they do not run on the same sites. What follows is ordered by a single question: who is this number accountable to? At the top, revenue figures that have to survive a buyer’s due diligence. At the bottom, traffic multiplied by an assumed conversion rate. This revision corrects three fee figures I got wrong the first time and demotes Flippa.

What this revision corrects

These are errors of fact, not of phrasing. They go first, because anyone who acted on the previous version needs to redo the arithmetic.

Acquire’s fees were wrong

The first version said “free to browse, 4% at close”. Sellers actually pay a monthly listing fee of $25 / $50 / $100 by asking-price band, plus 8% / 7% / 6% on close. Buyers on the free tier see public listings only; full access starts at $390 (pricing page, August 2026). Which means a seller is paying every month the business sits unsold.

Microns does not have zero commission

The first version said “free to browse, zero commission”. Neither half holds. Listing is free but closing costs 10% / 8% / 6% depending on whether the asking price is above $1K, $10K or $100K. Buyers on the free tier cannot see real revenue or contact the seller, and new listings are held back five days; unlocking costs $40 a month or $299 a year. The “zero commission” line is aimed at buyers.

Flippa does not belong in grade A

I filed it under “filed accounts” and then, in the same paragraph, said it was the most padded source on the page and its numbers should be halved. Both cannot be true. Flippa is open listing with no mandatory financial verification, so it moves to B. While correcting that: listing costs $29–99, or a $999 brokerage package above $100K, and the listing fee is not refunded if the business does not sell.

Four rules for reading these numbers

The trap with this category of site is not finding them. It is treating an estimate as a measurement. These four rules decide the ordering below, and how much to discount everything you read.

Rule 01

Ask who the number answers to

Someone selling a company has to produce Stripe statements, and the figure is accountable to a buyer — get it wrong and the deal dies. A directory site’s revenue column is traffic multiplied by a guessed conversion rate, accountable to nobody. An order of magnitude between the two is routine.

Rule 02

The traffic ranking beats the revenue ranking

Revenue is the outcome; the channel is the cause. Toolify’s regional and referral breakdowns tell you whether a product was built on SEO, social or paid. You can copy a channel strategy. You cannot copy a revenue figure.

Rule 03

The top of the list has no opening; the middle does

Capital and full teams have long since taken the head of every ranking. What is actually available is the band doing a few thousand to twenty thousand a month: demand is proven, and it is not yet large enough to be worth a big company’s attention.

Rule 04

Only marketplaces tell you the exit price

Acquire reports a median profit multiple of 3.9x for SaaS across 2024–25; Flippa puts micro-SaaS at a 2.85x mean with the top quartile reaching 6.13x. Both come from each platform’s own annual report, on definitions that do not match, so the two cannot be subtracted from each other. Orders of magnitude only.

Grade A

Filed accounts: verified by the platform, written for a buyer

Sellers disclose these voluntarily to close a deal, usually with payment-dashboard screenshots attached, and the platform does some verification of its own. The most trustworthy numbers available. The cost is that every sample is a business somebody wants to be rid of.

A-01 · Acquisition marketplace

Acquire.com

acquire.com

Formerly MicroAcquire, and the default venue for a bootstrapped SaaS exit. The platform states that 45% of listings are reviewed before going live and that the buyer pool exceeds 500,000 — its own claim, no methodology given, so do not lean on it.

Using it to find ideas

• Filter a category to the $1k–10k MRR band and read what that whole tier is solving
• Read the “why I’m selling” paragraph. That is where the real pain in the business is written down
• Note the categories that keep recurring. Three or more listings of the same thing means low barriers and willing buyers

What the fees actually mean

A seller pays the listing fee every month until the business sells, which filters out a certain amount of idle curiosity — listing quality here really is higher than Flippa’s. Buyers need $390 to see everything, and the free tier is public listings only, so what you see logged out has already been filtered for you.

The trap

What reaches this market is usually a business that has stopped growing. It answers what a business is worth, not whether it is a good business to be in. Reading listing density as category heat gets you the opposite of the truth.

A-02 · Small acquisitions

Microns

microns.io

Built for the $1,000–1,000,000 range, with a listing bar of real revenue, five months live and paying customers. The densest supply of businesses under six figures anywhere, and the closest thing to a realistic mirror of what one developer can actually build.

Why it is worth a separate look

Acquire skews larger. This tier is where you find the honest sample: one person, one year, a few hundred to a few thousand a month. If you want to know what a weekend project eventually turns into, this beats any ranking. Closed deals are published with both ARR and sale price, so you can compute the multiple yourself — one AI video tool with $6,900 ARR sold for $15K, a 2.2x.

The trap

On the free tier the revenue figures are blurred and new listings are held for five days. Without paying, what you are looking at is what everyone else already passed on. Inventory is also thinner than Flippa’s and updates are not frequent, so it rewards a scan every couple of weeks rather than daily attention.

Grade B

Checked: somebody verified it, or the sample corroborates itself

Two kinds of thing here. Case libraries where an editorial team checked each source, and open marketplaces where sellers self-report but the sample is large enough that the entries police each other. Not precise, but sound on direction and magnitude.

B-01 · Case library

Starter Story

starterstory.com/ideas

Around 2,990 profitable businesses, each revenue figure sourced and checked. The company publishes its own finances too: $1.6M ARR in 2026, bootstrapped.

The sections worth your time

• 990 problems, which is the same approach as the pain-mine field notes and can be cross-checked against them
• 676 micro-SaaS entries, median revenue $40K a month
• 782 automation and 930 freelance entries, the right places to look for a light start

The trap

Survivorship bias, heavily. Getting into the database requires having already made money. Use it to study how something was built. Using it to estimate a success rate produces nonsense.

B-02 · Open marketplaces

Flippa & SideProjectors

flippa.com · sideprojectors.com

Flippa carries the widest range of asset types and the most transactions of any established marketplace. SideProjectors is lighter, mostly side projects whose builders ran out of energy, and the listings include revenue, user counts and the stack.

They are useful for different things

• Flippa — category averages and multiple benchmarks; micro-SaaS averages 2.85x annual profit
• SideProjectors — the pairing of stack and revenue, which tells you how far a given implementation path can carry a business

Why it moved down to B

Flippa does not require financial verification, so any figure without a payment-dashboard screenshot gets halved on sight. What it is genuinely good for is sample size: put forty listings in one category side by side and the average is far more reliable than any single entry. Use it for benchmarks, never for a specific business.

Grade C

Estimated: derived from traffic

Third-party traffic multiplied by an assumed conversion rate and an assumed price. Magnitudes are usable, individual figures are not. What they have going for them is breadth, refresh rate, and the ability to show a trend.

C-01 · AI revenue ranking

Toolify

toolify.ai/en/Best-AI-Tools-revenue

The most widely used source in the China-to-global indie scene. Revenue is inferred from payment-platform rankings crossed with monthly traffic, sourced from Similarweb, refreshed monthly.

Ignore the revenue ranking

The valuable parts are the traffic, regional and referral rankings: monthly visits for a given AI tool, where the visitors are, and how they arrived. You cannot copy a revenue figure. You can copy the answer to whether something grew on SEO or on social.

The trap

There is bot protection — scripted fetches get a 403, a browser is fine. Revenue is an estimate, and being an order of magnitude off real MRR is not unusual. I have seen the ranking claim six figures a month for a product whose founder was posting about three thousand.

C-02 · From complaint to revenue

BigIdeasDB

bigideasdb.com

Around 2,400 startups tagged with revenue, organised along a chain from Reddit complaint to competitor revenue to market gap. The closest thing in approach to the pain-mine notes, which makes it useful as a verification layer downstream of them.

How to pair them

• Pull a complaint out of the field notes, then check here whether anyone is already building it
• Someone is, and has revenue: the demand is real, go find an angle
• Several are, and none has revenue: usually a false signal, or nobody will pay for it

The trap

The blog is heavily SEO-farmed and reads like it; the database is more reliable than the articles. Frequent scraping trips a 429.

C-03 · Competitive intelligence

Proven SaaS & Getlatka

proven-saas.com · getlatka.com

Proven SaaS holds estimated MRR for around 14,500 companies in the $10k–500k band, with Facebook ad creative and stack detection attached. Getlatka leans B2B and its numbers are mostly founder-reported.

The ad library is the valuable part

Not the revenue. Being able to see what a product is currently running — which images, which copy, aimed at whom — is the cheapest marketing intelligence available, and the free tier covers it. I have never once used the revenue column.

The trap

Neither company publishes its estimation method. Getlatka’s founder-reported figures skew high, which is widely accepted in the industry and which nobody has ever quantified.

Grade D

Timely: no revenue data, but you see new things first

These cover the blind spot in the three grades above. Those tell you what has already made money. This one tells you what just shipped.

D-01 · Launch tracking

Uneed

uneed.best

Currently the most credible Product Hunt alternative. 64,000 makers, roughly 580,000 monthly visits and 1.87M page views in 2026 — the platform’s own figures.

Why it beats Product Hunt

PH decides everything inside 24 hours, so its ranking measures how many people you can mobilise more than what you built. Uneed keeps a launch on the weekly and monthly boards afterwards, and anything that survives a week on the weekly board usually has actual users.

The rest of the set

• Microlaunch — ranked monthly, a slower and more honest rhythm
• Fazier / Peerlist Launchpad / Tiny Startups / Dev Hunt — niche; I have only opened the front pages
• BetaList for things not yet launched, AppSumo for things already selling

D-02 · Mobile

Appfigures

appfigures.com

The most useful free tier for anyone working on apps. It publishes monthly “most downloaded / highest grossing” articles that read without a login, and its pricing is the most transparent in the category.

Three others in the same lane

• AppMagic — free tier includes revenue and download estimates, enough for category research; acquired by Sensor Tower in May 2026
• Sensor Tower — the most complete data and priced accordingly; the free State of Mobile and State of AI reports are enough for trend work
• AppBird — an independent alternative from $99 a month, with an ad creative feed and technical breakdowns

What is getting worse here

Sensor Tower absorbed data.ai in 2024 and AppMagic in 2026. Independent sources in this category are disappearing fast and free allowances can tighten without notice. Whatever you can pull for free today, pull it and keep a copy.

Three Chinese-language additions

Lower information density than the English sources, but they carry local perspective and will save you some of the tuition. Useful only if you read Chinese.

indiehackertools.net

Indie Hacker Tools

A toolbox for Chinese developers selling abroad, organised by build, design, marketing and analysis. The valuable piece is a list of 300-plus distribution channels — the thing to reach for when the product is done and you have no idea where to post it.

91wink.com

独立开发前线

Ongoing teardowns of Western products’ traffic sources and revenue structure, with more depth per piece than most Chinese-language coverage of the space. Read it weekly; do not treat it as a data source.

indiehackers.com

Indie Hackers & r/indiehackers

Free, first-hand, noisy. The Show section and the revenue threads are raw material, and the monthly revenue reports in the forum are fresher than any secondary ranking. The price is that you do the filtering.

If you only keep three

These run in order, and each step feeds the next. Swap the order and you will spend your time on the wrong thing.

Step one

Toolify, to pick the ground

What are people actually using?

Read the traffic ranking, not the revenue ranking, and find categories where monthly visits are rising and the head of the market is not yet concentrated. Write down where their traffic comes from; that decides which channel you will be fighting on later.

Step two

Acquire, to price it

What is this business worth?

Search for comparable businesses and look at real closing ranges and multiples. If similar things have been listed for six months without selling, the direction is hard to monetise even if you build it well. Killing an idea here is far cheaper than killing it after you have built it.

Step three

Starter Story, to learn the path

How did they actually get there?

Find two or three verified cases in the same category and read how they started, how pricing evolved, and where the first users came from. This step gives you execution detail. The first two only gave you a direction.

The whole list

Ordered by grade. The data column is what tells you how much to discount. A dagger marks the ones I have only listed, not used.

Source	Grade	Nature of the data	Cost	Best question for it
Acquire.com	A filed	seller-filed, platform-verified	buyers from $390	What is this business worth
Microns	A filed	seller-disclosed, small enough to check	buyers $299/yr	What can one person’s project become
Starter Story	B checked	editorially checked and sourced	free plus Premium	How did they build it
Flippa	B checked	self-reported, corroborated by volume	free to browse	Category multiple benchmarks
SideProjectors	B checked	self-reported, includes the stack	free	What a given stack can carry
Getlatka †	B checked	founder-reported, skews high	partly free	B2B SaaS revenue magnitudes
Toolify	C estimated	inferred from Similarweb, monthly	free	Which channel an AI product grew on
BigIdeasDB	C estimated	scraped and aggregated	partly free	Is anyone already building this
Proven SaaS	C estimated	estimated MRR plus ad creative	free tier plus paid	What ads a competitor is running
IdeaProof †	C estimated	curated list with difficulty scores	partly free	A fast pass over candidates
Uneed	D timely	votes plus sustained ranking	free	What just launched
Microlaunch †	D timely	monthly ranking	free	What held its attention
BetaList †	D timely	pre-launch projects	free to browse	What the next wave is building
Appfigures	D timely	store charts plus modelling	free tier	Who is earning on mobile
AppMagic	D timely	download and revenue estimates	free tier	App category research
Sensor Tower †	D timely	modelled, the most complete there is	reports free, subscription expensive	Mobile market trends

Not worth your time

These take up a lot of room in search results and contribute nothing to a decision.

“50 profitable ideas for 2026” articles

SEO content written for a keyword, ideas copied between sites, revenue figures with no source. A number and a year in the headline is enough reason to skip it.

The Product Hunt daily board

A 24-hour voting window measures how many people a team can mobilise. If you must, read the weekly and monthly boards, or use Uneed instead.

A full Sensor Tower subscription

Terrible value for one person building products. The free industry reports already cover the trend work, and the free AppMagic tier handles category research.

Third-party “revenue ranking” aggregators

The data is lifted from Toolify or Similarweb with another layer of guessing on top, so the error compounds twice. If you want an estimate, go to the source of it.

What I did not verify

Stated so you know where the edge of this list is.

Six sources are listed, not used

The six marked with a dagger — Getlatka, IdeaProof, Microlaunch, BetaList, Sensor Tower, and the Fazier group mentioned under D-01 — I have only opened the front page of. Neither pricing nor data quality was checked. Do not read their grade as a conclusion.

The multiple benchmarks are not on comparable definitions

Acquire’s 3.9x and Flippa’s 2.85x come from two separate annual reports. One may be computed on SDE and the other on net profit, so the denominators are not necessarily the same quantity. Compare orders of magnitude, never the difference.

Toolify’s error rate is not quantified

“An order of magnitude” is an impression formed from scattered cases, not a statistic. If you intend to make a real decision on it, take three to five products whose actual revenue you know and check the ranking against them yourself.

Where I could be wrong

This list rests on two assumptions. If either fails, the ordering has to be rebuilt.

Assumption 01

Seller-filed numbers beat third-party estimates

Which holds only if the platform genuinely verifies. If Acquire’s “45% reviewed” turns out to be a formality, the gap between grade A and grade C is much narrower than I have drawn it. To test it: find several completed sales on a grade-A platform and get the buyer’s account of what the numbers turned out to be.

Assumption 02

The middle of the market has the opening

True for tools. Not necessarily true where network effects apply, because there the winner takes it and the existence of a mid-sized player is itself a failure signal. To test it: take a few two-sided categories and measure the two-year survival rate of businesses doing $5k–20k a month.

Fees and pricing verified in August 2026 from each platform’s own pricing page. Grade A figures come from sellers; grade C figures are inferred from traffic. The two are not comparable.

Earlier in this series: Pain Mine, part one · part two. Those dig up the complaints; this one decides whether a complaint is worth money.