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Key Features


Lemon is open source and uses open source components. The best advantage of being open source is that you own your information and you are free to move where you want without being tied to a provider.

Other advantage is that it gives you the freedom to study the source code, and if you know how, you can adapt it to your needs, correct bugs you find and help to improve it. And, if you dont know how to do this, you can request features, report  bugs, or hire someone to adapt it.

Safer Environment. 

Being linux or any unix system the target operating system to run lemon on, makes a safer place for your information against virus attacks, and also lowers the costs in operating system and antivirus licenses.

Single Database, Multiple Terminals.

 You can have a single database serving multiple POS terminals. With other comercial products you must pay for each terminal, with lemon you can have as many as you need without worring about license fees for each one.


Vendor's Interface Features

known as “lemon”.

Simple and Appealing.

The Vendor's Interface —lemon— is kept simple for best operation. It can be themed using stylesheets and images to fit your tastes or store image. The tickets printed on modern thermal printers, together with the use of barcode scanners, are a plus for your store presentation, as a result all modern tools used gives a more attractive and professional image of your business to your clients.

The Lemon User Interface



  • Enter product's code with a barcode scanner to increase vendor productivity.
  • Enter purchase amount in the same input area, like “100x12345678”, to add many items at a time.
  • Staying focused the code's inputbox, use the “+” key on the keypad to go enter the payment amount.
  • Searching for products by description, just press “F3” key to open the sarch panel.
  • Open a price checker tool to easily know prices for products without adding them to the purchase. And here you can also use the barcode scanner.
  • Apply occasional discounts —with admin/supervisor permission— to a sale it's breezing.
  • Suspend and resume sales, to interrupt a sale, start another sale and resume the saved sale later.
  • A Low Security Mode just for convenience.


  • Balance for each vendor at the end of its session.
  • End of day report directly at the POS terminal.
  • Taxes are printed on tickets. Per product, and total sale taxes.
  • Reprint tickets
  • Extra messages on tickets.


  • Role based permissions.
  • Logged important vendor actions: like cash-in/out,cancelling transactions.
  • Lock screen: for vendor urgent/small absence.


  • Categorized products
  • Group products (packs)
  • A grid for showing products with photos. Filter by category,name...
  • Supports Clients, having their information. Discounts based by client.


  • Enter old, non registered in lemon, sales with the “Change Sale Date” button.
  • Cash flow. Cash-in/Cash-out, money need to enter/leave to/from the cash drawer, in other way than paid money/change given.
  • Support for a loyalty program, clients accumulate points, based on each product.
  • Special Orders, this are custom products that are formed of raw products.


Administrative Interface Features

known as “squeeze”.

With squeeze you can manage your store and get valuable information in which base your decisions to improve your business.

ADD UI for squeeze!


There are on screen and printed reports, information to use for restocking and take decisions for you business health.

  • Transactions (sales, purchases) per day, month, vendor, terminal, date, status, type...
  • Balance filtered by vendor, date, amount...
  • End of day/month.
  • Low stock products.
  • Sold out products.
  • Cash flow, in/out money other than regular sale process.
  • Special orders.

Inventory Control

  • Manage your inventory. know what needs to restock, what is not sold, what is most sold.
  • Register purchases, and autocorrect stock.
  • Any loss of products or supervising your warehouse? Make stock corrections.
  • Add product's photo. 
  • Make any group product for promotions or packages.
  • Create raw products for special orders or custom products.
  • Categorize your products.
  • Set product's selling measure.
  • Assign barcode to products to improve the sale time.

Manage the different information available on database

Modify, add and delete:

  • Offers or promotions
  • Vendors
  • Clients
  • Categories
  • Weights/Measures
  • Ticket Messages


Tested Devices

Most barcode scanners (usb, ps2) are easy to install because they dont need a driver, they act as simple keyboards. Some printers (mainly thermal) are provided with a CUPS driver for unix/linux systems and those printers are already supported in lemon (after installing the driver) by choosing the CUPS printing setting. 


  • Star Micronics Thermal Printer. Model TSP100 [ TSP143 ]
  • Star Micronics Matrix Printer. Model SP500 (parallel port, using /dev/lpX port)

Barcode Scanners

  • Datalogic Barcode Scanner. Model DLC6065-M0

If you use another device, please send an email for adding it here.


Not found what you need?

If you need special features or adaptation to your business, we can work for you. We accept donations for small works that benefit you and the community, but also we can talk about a special work for you. Contact us.