Ledger is a REST-ful double-entry accounting software. Its main principle is simplicity. Currently it allows you to:

1. Create a chart of accounts.
2. Record transactions affecting the accounts.
3. Generate a balance sheet corresponding to any point in time.
4. Generate an income statement corresponding to any interval of time.

You need Python 2.7 and virtualenvwrapper.

# Step 1: Clone the repository
git clone https://github.com/gregnavis/ledger.git ledger

# Step 2: Enter the project root
cd ledger

# Step 3: create a virtual environment
mkvirtualenv -a "${PWD}" -r requirements.txt

# Step 4: set environment variables
export FLASK_APP=webapp.py

# Step 5: initialize the database
flask init

# Step 6: run!
flask run --host=0.0.0.0

Ledger is listening on port 5000 on all interfaces.

First, you need to create the chart of accounts. You can do this by POST-ing the following JSON to /accounts:

{"name":"Cash","code":"101","type":"asset"}

This will create an account named Cash. The name of an account is only for display purposes. Accounts are internally references using the code. For example, if you GET /accounts/101 the server will return the data you've posted to created the account.

There are five types of accounts: asset, liability, equity, revenue and expense. Before recording your first transaction, you need some other accounts, say Equipment (an asset account) and Share Capital (an equity account). You can create them by POST-ing:

{"name":"Equipment","code":"102","type":"asset"}

and

{"name":"Share Capital","code":"301","type":"equity"}

You'll also need a revenue account:

{"name":"Consulting Revenue","code":"401","type":"revenue"}

For simplicity, we'll skip expenses.

With the chart of accounts in place, you're ready to start recording transactions. In order to record the initial investment of $10,000 POST the following to /transactions:

{
  "date":"2016-09-01",
  "description":"Record the initial investment",
  "items":[
    {"account_code":"101","amount":1000000},
    {"account_code":"301","amount":-1000000}
  ]
}

The convention is that positive amounts are debits, negative are credits. Also, all amounts are assumed to be expressed in cents hence 1000000.

If you buy an asset, e.g. a laptop for $2,000, you can record it with:

{
  "date":"2016-09-02",
  "description":"Buy a computer",
  "items":[
    {"account_code":"101","amount":-200000},
    {"account_code":"102","amount":200000},
  ]
}

A consulting service for Acme, Inc., paid $1,500 in cash, can be recorded as:

{
  "date":"2016-09-03",
  "description":"Consulting for Acme, Inc.",
  "items":[
    {"account_code":"101","amount":150000},
    {"account_code":"401","amount":-150000},
  ]
}

To see the balance sheet on 5 September 2016 go to /balance-sheets/2016-09-05.html. You should see

Similarly, if you go to /income-statements/2016-09-01-to-2016-09-05.html you should see:

To sum up:

• POST /accounts creates an account.
• GET /accounts/<code> retrieves account information.
• POST /transactions record a transaction.
• GET /balance-sheets/<YYYY-MM-DD>.html generates a balance sheet on a given day.
• GET /income-statements/<YYYY-MM-DD>-to-<YYYY-MM-DD>.html generates an income statement corresponding to a given period of time.

Ledger has minimal dependencies. It stores data in SQLite 3 using the built-in sqlite3 module. The web component uses Flask and Jinja 2.

Financial accounting is a huge subject. Ledger is not a fully-fledged accounting system. Below is a list of things that it lacks:

• Adjusted and unadjusted trial balances.
• Statement of changes in equity.
• Contra accounts.
• Classified balance sheets and income statements.
• Subledgers.
• Automatic capitalization, depreciation and amortization.
• Industry-specific financial statements (e.g. income statements reporting cost of goods sold and gross profit in a merchandising business).
• Inventor systems (perpetual and periodic).
• Cost flow assumptions (specific identification, FIFO and weighted average).
• Estimation of balance in merchandise inventory (gross profit method and retail inventory method).
• Notes to financial statements.
• Security features (e.g. SSL, authentication).
• Configuration knobs (e.g. database location, network interface to use).

If you'd like to help to implement a feature feel free to drop me a line. I'll try to give you some guidance.

Ledger is developed and maintained by Greg Navis.