Mary Jane Knows
ESApply for the beta

Less hype. More flower.

Mary Jane Knows is a desktop app. Mary reads the flower in your stores, compares it with the flowers you have loved, using lab-measured terpene data, and shows you which ones best match your taste. So you can find your favorites, find them again, and enjoy them.

Apply for the betaHow Mary finds your gem

Beta · 22 spots in the US · applications close Nov 17

Mary, the drawn guide of Mary Jane Knows, pointing to the beta.

5 entries · your journal is 50% of your profile

0121% THC
Jh
Jack Herer
Smells like fresh herbs,pepper
Terpinolene43%Caryophyllene20%Pinene10%
CreativeFocused
Green Door · IndoorOct 12, 2026
0219% THC
Dp
Durban Poison
Smells like fresh herbs,mango
Terpinolene46%Myrcene13%Pinene13%
FocusedDry mouth
Green Door · IndoorOct 4, 2026
0320% THC
Sl
Super Lemon Haze
Smells like fresh herbs,pepper
Terpinolene34%Caryophyllene20%Myrcene14%
CreativeHungry
Green Door · IndoorOct 5, 2026
0418% THC
Tr
Trainwreck
Smells like fresh herbs,mango
Terpinolene29%Myrcene18%Caryophyllene14%
Relaxed
Green Door · IndoorOct 8, 2026
0519% THC
Bd
Blue Dream
Smells like mango,pine
Myrcene35%Pinene34%Caryophyllene16%
RelaxedHungry
Green Door · IndoorOct 10, 2026

Example labels, drawn the way the app prints them. For adults 21+, where it is legal.

Find your gem. Then find it again.

Your gem is a flower that suits what you are looking for on a particular occasion, without the qualities you want to avoid. Mary keeps one shelf for each thing you use flower for. Chemistry narrows the candidates; what you log decides.

Mary: You put the crown on. I keep watch.

Mary holding a small glass jar of flower.

  • Say what it is for

    Creating, a movie, unwinding after the day: each use gets its own shelf and its own profile, so two favorites that are nothing alike stop blurring into one.

  • Mary narrows it down

    Mary looks at the flowers your stores have today and finds the ones whose chemistry is closest to that shelf. She shows you how each one differs.

  • Try it, and say if it worked

    When you log a flower, note what you wanted it for and whether it worked for you. The next morning, add how you woke up. You still won’t see the match score while logging.

  • You crown it

    Did it work for you, without anything you’d want to avoid? Mary asks if it is your gem. Only you can say yes.

  • She tells you when it is back

    When your gem, or one almost identical, shows up in one of your stores, you hear about it.

A drawing of “Your gems” in the app, with example data.

Almost a gem? Two ways forward.

Some strains give you exactly what you want and leave something you do not, like tension the next morning. Mary opens two paths at once: the same chemistry in another flower, or the same strain a different way, changing one thing at a time and logging how you woke up. This is a way to explore, not a promise about how you’ll feel: no terpene has been shown to determine how you feel the next day.

A method, not a promise that you will find it. And a heads-up when it comes back.

Your journal is what makes Mary better.

At first Mary only knows what you told her. Every time you write down how a flower went, the suggestions lean less on that and more on what really happened to you. It is the most important part of the app.

What your profile is made of

No entries0%
5 entries50%
15 entries75%

Your journalWhat you said at the start

  • It takes a minute

    A rating, what you wanted it for and whether it worked, the good and the bad. Blind, without seeing the number.

  • It weighs more every time

    With 5 entries, your journal already makes up half of your profile. With 15, three quarters.

  • Recent counts more

    Taste changes. An entry from a year ago weighs half of one from today.

  • Mary answers for it

    The app keeps what it predicted before you rated, and shows you how often it was right.

Eight things Mary does for you.

This is a drawing of the app, with example data.

Your settings

Stores

Green Doorgreendoor.example · 180 flowersUSD×
High Desert Flowerhighdesert.example · 94 flowersUSD×
La Esquinalaesquina.example · 71 flowersUSD×
greendoor.example/menu
Add
Reading the menu…

Paste the address of your store or of its online menu. I check them every 6 hours.

Flower only: 212 other products left out

Behind every match, 167,381 lab tests.

The app carries a lab index of 14,723 strains, built from public data. It travels with the app: no account, nothing in the cloud.

Mary looking at a bud through her jeweler’s loupe.
In your library
Sativa19% THC
Jh
Jack Herer
Fits you · 97%$8.9/g
New
Sativa19% THC
Dp
Durban Poison
Fits you · 91%$9.1/g
2 options
Sativa20% THC
Sl
Super Lemon Haze
Fits you · 88%$8.6/g
Hybrid18% THC
Tr
Trainwreck
Fits you · 84%$7.4/g
Hybrid19% THC
Bd
Blue Dream
Match 58%$8/g
Sativa17% THC
Ta
Tangie
Match 52%$10/g
2 options
Hybrid22% THC
Ma
MAC 1
Match 44%$12/g
Hybrid24% THC
Wc
Wedding Cake
Match 41%$11/g
Hybrid25% THC
Ru
Runtz
Match 36%$13/g
Indica28% THC
Gm
GMO
Very high THC
Indica17% THC
Pp
Purple Punch
Blacklist
Hybrid
Mm
Moon Mango
No data$9/g
An example: what your stores have today, if you like Jack Herer.

Everything visible, everything informed.

One card per strain, like an element in a table. You read a whole store at a glance, and every part of the card means something.

What each part says
  1. 1

    Options

    The same strain in another size, brand or lot is one card with several options.

  2. 2

    Type and THC

    What the store says, and the THC of the lot. “≈” when it is the typical value of the strain.

  3. 3

    Two letters

    In the color of the dominant terpene.

  4. 4

    The bar

    The terpene profile. Each terpene always has the same color.

  5. 5

    The match

    Calculated by the app. When it fits you, the card says so in words.

  6. 6

    The price

    Per gram, for the cheapest size, in the store’s own currency.

The five states of a card
  • Sativa19% THC
    Dp
    Durban Poison
    Fits you · 91%$9.10/g

    Fits you75% or more, on solid data

  • Hybrid19% THC
    Bd
    Blue Dream
    Match 58%$8/g

    NeutralHas data, under 75%

  • Indica28% THC
    Gm
    GMO
    Very high THC

    Not for youDiscarded, with the reason

  • Indica17% THC
    Pp
    Purple Punch
    Blacklist

    BlacklistYou never want to see it

  • Hybrid
    Mm
    Moon Mango
    No data

    No dataNobody has measured it

One color per terpene, from its aroma
  • Myrcenemango, earth
  • Limonenelemon
  • Caryophyllenepepper
  • Pinenepine
  • Linaloollavender
  • Humulenehops, wood
  • Terpinolenefresh, herbal
  • Ocimenesweet, floral

The color never goes alone: it always comes with the name.

Label printerA card-shaped label for Jack Herer in black and white: the letters Jh, 21% THC, smells like fresh herbs and pepper, three terpene bars, three effects, the store and the date.The same label as a round sticker for the lid, in black and white.
Color printerThe same card label in color: the letters in terpinolene blue, the terpene bars in their colors and the effects in lavender pills.The same label as a strip, in color, with the letters on a pale blue block.
Card · 50 × 62 mm · Strip · 62 × 29 mm · Lid · 56 mm circleExamples, exactly as the app prints them.

Take the card to the jar.

Any strain prints as a label for the jar where you keep that flower: in black and white for a label printer, or in the strain’s colors for an inkjet or laser printer. Three sizes, one of them round for the lid.

What it carries, and what it leaves out

  • What it carries

    The two letters, the name, your library number, the THC, the aroma and the three main terpenes, with the store and the date.

  • What you felt

    If you logged that strain, the label shows the effects you wrote down. They come from your journal, not from a promise.

  • What it leaves out

    The match and your rating. Seeing them on the jar would sway you the next time you rate it.

  • Two printers

    A label printer (thermal, like the Brother QL) prints it in pure black and white on a 62 mm roll. A color printer prints a letter-size PDF at real size, with a cut line, on sticker or plain paper.

Chemistry over folklore.

We read the studies before writing the match. A few things did not survive.

Mary with her arms crossed, relaxed, half smiling.

  • Indica and sativa do not predict the chemistry

    The card says “Sativa according to the store”. It is a label, never a promise.

  • No promised effects

    Mary is sure about the aroma. Effects come only from what you wrote in your own journal.

  • The number is not dressed up

    It is not inflated to look good. When the data is weak it says “Estimated” and the flower is not recommended.

  • No medical advice

    This is a tool to choose flower. It is not medicine and Mary is not a doctor.

The AI does not decide. The math does.

The match is calculated by the app from lab data. The AI is optional and does two things. Everything it does is marked in this purple, so you always know when it is the AI talking.

This is a drawing of the app, with example data.

You pay your AI provider, not us. The app shows the approximate cost before it spends anything.

What the AI does, and what it costs

  • Mary explains

    Ask and she explains a flower in plain words: the aroma, and which of your strains it resembles.

  • Research on request

    For a strain nobody has measured, the AI searches the web and keeps its sources. Only when you ask, and the button says what it costs.

  • Your own connection

    Connect OpenRouter with one click, or use a Claude or OpenAI key. Advanced: Codex or Claude Code with your subscription.

  • Works without it

    Without AI you still have the index, the match, your stores and your journal.

Your taste stays on your computer.

No account and no cloud. The app keeps everything in one file on your machine.

Stays with you

  • Your profile, your library and your journal
  • Your stores and what they had
  • Your keys, in the system keychain

Leaves, and when

  • Requests to the stores you added, to read their menus
  • Once a day, a question to mjknows.com: is there a newer lab index? It sends nothing of yours, and you can turn it off
  • When you ask Mary to explain: the flower, your strains it resembles and what you logged about them, to the AI provider you chose
  • When you ask for research: the name of the strain, to that same provider

This site has no cookies and no trackers. Your browser only remembers that you said you are 21 or older, and the theme you picked.

All of it, on the table.

  • Online stores, by address

    Mary Jane Knows is made for stores that sell online. Paste the web address and Mary reads the menu. It works with the online menus of most dispensaries and with shops on Shopify, WooCommerce and Zoho.

  • Flower only

    Pre-rolls, infused buds, loose shake, edibles and concentrates stay out. Smalls and popcorn stay in: they are whole buds.

  • New arrivals

    What came in at each store, each day, sorted by what fits you.

  • Your gems

    One shelf per thing you use flower for, with its own profile and candidates from your stores. You crown the gem, and Mary tells you when it is back.

  • Match with reasons

    “Why 91%” shows what added and what subtracted, and where the flower ranks among everything in your stores.

  • The lot, when the store publishes it

    If the menu shows the terpenes of the lot, the match uses those and not the average of the strain.

Twelve more things it does

Your stores

  • One card per strain

    Different sizes, brands or lots of the same strain appear as options on one card, each with its own match score and price.

  • Prices as they are

    Price per gram in each store’s currency. Nothing is converted.

  • In the background

    It sits in the tray, checks your stores every 6 hours and sends a system notification when something arrives.

Your taste

  • A lab index inside

    14,723 strains and 167,381 lab tests from public sources travel with the app, and it downloads the newer index when there is one. Most strains need no research.

  • Library and blacklist

    The strains you like, the ones you saved to try, and the ones you never want to see again.

  • Blind journal

    The most important part: it is what improves your suggestions. You rate without seeing the number, and the app shows how often it got it right.

  • It learns from you

    Every entry weighs more than what you said at the start, and recent ones weigh more than old ones.

The rest

  • Search

    Any strain, in your stores or in the index. Ctrl/Cmd+K.

  • Start your way

    A full first setup, or skip it and just keep a journal. In English or Spanish: you switch without restarting.

  • Fix a strain

    If a product was matched to the wrong strain, correct it once and it holds in every store.

  • Backup

    Everything exports to one file. Your keys are not in it.

  • Mary flags the odd ones

    If the lot in the store does not carry the usual dominant terpene of the strain, or a grower sells the same lot under another name, she says so.

  • What the store says

    The effects a store publishes are shown apart, as “The store says”. They do not move the number.

Fifteen years in, I just want flower.

I started late, at 35, with a lot of respect for the plant. A lifelong friend showed me the way. He knew nothing technical, but he knew how to take care of the moment and the place. Cannabis came into my life at a hard time, and it helped me see things differently. I never forgot it.

Then I went for more, like everyone: pre-rolls with diamonds, carts, edibles, resin. Everything got stronger. My experiences got worse.

So I went back to flower. Plain flower. I kept refining how I enjoy it, step by step, until the day I finally understood what sommeliers meant: flower really can taste like fruit.

Then came the hard part: finding it again. I bought a gram at a time, and when I came back for the one I loved, it was gone. Strain after strain, new names every week, and I did not want to spend my time at the store figuring out which jar matched my taste.

So I made Mary Jane Knows. She watches your stores, compares every flower with the ones you have loved, and tells you when one that fits you arrives. I wanted less hype, and more of the flower I actually enjoy.

Less hype. More flower.

— Maxx Darko

Be one of the 22.

Before launch, 22 people in the US test Mary Jane Knows for two weeks and tell us, honestly, whether she picks the right flower. In return, the full version is yours, free, for life. Applications close November 17; the beta starts November 23.

Apply for the beta

At launch it will be free, with 14 days of everything. The extras are paid once. No subscription.

Mary holding out an open hand, inviting you in.
  • For Windows, Mac and Linux
  • In English and Spanish
  • No account, nothing in the cloud
  • Flower only