Ledger

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

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

Installation

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.

Usage

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.

Under the Hood

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

Missing Features

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.

Author

Ledger is developed and maintained by Greg Navis.