OFX Kit

A Ruby gem for parsing OFX (Open Financial Exchange) files. Supports OFX 1.x (SGML) and OFX 2.x (XML), bank statements and credit card statements, with a fluent API and configurable field mappings.

Installation

Add to your Gemfile:

gem "ofx_kit"

Usage

Basic parsing

# Parse from a file path
ofx = OFX.new("statement.ofx")

# Parse from an IO object
ofx = OFX.new(File.open("statement.ofx"))
ofx = OFX.new(StringIO.new(raw_content))

# Block form — yields the parser
OFX.new("statement.ofx") do |p|
  puts p.account.account_id
end

Accessing data

ofx.filename      # => "statement.ofx" (nil for IO inputs without a path)
ofx.headers       # => { "VERSION" => "102", "ENCODING" => "USASCII", ... }

# Single-statement files
ofx.account       # => OFX::BankAccount or OFX::CreditCardAccount
ofx.transactions  # => Array of OFX::Transaction
ofx.balance       # => OFX::Balance

# Multiple-statement files — use the plural forms
ofx.accounts      # => [OFX::BankAccount, ...]
ofx.statements    # => [OFX::BankStatement, ...]
ofx.balances      # => [OFX::Balance, ...]

Transactions

t = ofx.transactions.first

t.fit_id        # => "20240115001"       String
t.type          # => "DEBIT"             String
t.memo          # => "Pagamento boleto"  String
t.posted_at     # => Time object
t.amount        # => Money object (positive = credit, negative = debit)
t.amount_cents  # => Integer (same as t.amount.fractional)

t.amount.currency.iso_code  # => "BRL"
t.amount.to_d               # => BigDecimal("-150.50")

Credits, debits, and scopes

stmt.transactions and account.transactions both return an OFX::TransactionCollection with .credits, .debits, length, and the full Enumerable API:

stmt = ofx.statements.first
txns = stmt.transactions           # => OFX::TransactionCollection

txns.length                        # => 2
txns.credits                       # => TransactionCollection of positive amounts
txns.debits                        # => TransactionCollection of negative amounts
txns.total_credits                 # => Money (sum of positive transactions)
txns.total_debits                  # => Money (sum of negative transactions)
txns.net                           # => Money (total_credits + total_debits)
txns.map(&:memo)                   # => ["Pagamento boleto", "Deposito salario"]
txns.sort_by(&:posted_at)          # => Array, sorted by date

Balance

bal = ofx.balance
bal.amount        # => Money object
bal.amount_cents  # => Integer
bal.posted_at     # => Time object

Summary

ofx.summary
# => {
#   headers: { "VERSION" => "102", ... },
#   statements: {
#     "12345-6" => {
#       currency:      "BRL",
#       transactions:  { count: 2, net_cents: 284_950 },
#       credits:       { count: 1, total_cents: 300_000 },
#       debits:        { count: 1, total_cents: -15_050 },
#       balance_cents: 500_000
#     }
#   }
# }

Error handling

OFX.new("missing.ofx")      # => Errno::ENOENT
OFX.new("bad_header.ofx")   # => OFX::InvalidHeaderError
OFX.new("bad_xml.ofx")      # => OFX::InvalidBodyError
OFX.new(42)                 # => ArgumentError

# Calling #account or #balance on a multi-statement file:
ofx.account   # => OFX::MultipleStatementsError (use `accounts`)
ofx.balance   # => OFX::MultipleStatementsError (use `balances`)

Configuration

Field mappings

Use map to add new attributes or rename built-in ones:

OFX.configure do |config|
  # New field: your bank emits a tag the gem doesn't know about by default
  config.bank_account.map "AGENCIA",      to: "branch_code"
  config.transaction.map  "HISPAYEEMEMO", to: "extended_memo"

  # Rename a built-in field to a name that fits your domain
  config.transaction.map "FITID", to: "uid"   # default is fit_id
  config.transaction.map "NAME",  to: "payee_name"
end

ofx = OFX.new("statement.ofx")
ofx.account.branch_code               # => "0272"
ofx.transactions.first.extended_memo  # => "Tarifa bancaria"
ofx.transactions.first.uid            # => "20240115001"
# ofx.transactions.first.fit_id       # => nil (FITID is now mapped to uid)

Protected core fields — CURDEF, TRNAMT, DTPOSTED, DTUSER, BALAMT, DTASOF are used internally to build Money objects and parse dates. They cannot be renamed; attempting to do so raises OFX::ConfigurationError.

Loading mappings from a YAML file

For larger configurations or Rails apps, a YAML file is cleaner than inline map calls.

Rails — eject the template with:

rails generate ofx:eject

This creates config/initializers/ofx_mappings.yml, which the gem detects and loads automatically on boot — no OFX.configure call needed.

Standalone — point load_mappings at any YAML file:

OFX.configure do |config|
  config.load_mappings("config/ofx_mappings.yml")
end

The file must have a FIELDS: top-level key:

FIELDS:
  STMTTRN:
    HISPAYEEMEMO: extended_memo   # → transaction.extended_memo (new field)
    FITID: uid                    # → transaction.uid  (default was fit_id)
  BANKACCTFROM:
    AGENCIA: branch_code          # → account.branch_code (new field)

Silencing warnings

transactions and balances aggregate across all statements in a multi-statement file and emit a warning. To silence them:

OFX.config.multi_statement_warnings = false

Currency

The OFX specification requires CURDEF in every statement (STMTRS / CCSTMTRS). If the tag is absent, the gem raises OFX::Errors::InvalidBodyError rather than silently assuming a currency.

Rails

Behavioral options — create a standard initializer:

# config/initializers/ofx.rb
OFX.configure do |config|
  config.multi_statement_warnings = false  # silence aggregation warnings
end

Contributing

Fork the repository and create a feature branch.
Install dependencies:

   bundle install

Make your changes. Add or update specs to cover them.
Run the test suite and linter before opening a pull request:

   bundle exec rspec
   bundle exec rubocop

All tests must pass and RuboCop must report no offenses.

Testing locally via console

You can exercise the gem interactively using irb from the project root. The spec/fixtures/ directory contains sample OFX files ready to use.

bundle exec irb -r ./lib/ofx_kit

# Parse a bank statement (OFX 1.x)
ofx = OFX.new("spec/fixtures/bank_simple.ofx")
ofx.account.account_id   # => "12345-6"
ofx.transactions.length  # => 2
ofx.balance.amount       # => Money object

# Parse an OFX 2.x file
ofx = OFX.new("spec/fixtures/bank_ofx2.ofx")
ofx.headers              # => { "VERSION" => "220", ... }

# Parse a credit card statement
ofx = OFX.new("spec/fixtures/credit_card.ofx")
ofx.account              # => OFX::CreditCardAccount
ofx.transactions.first.amount.to_d  # => BigDecimal

# Multiple statements
ofx = OFX.new("spec/fixtures/bank_multiple.ofx")
ofx.accounts.length      # => 2
ofx.statements.map { |s| s.account.account_id }

# Try custom field mappings
OFX.configure do |config|
  config.transaction.map "HISPAYEEMEMO", to: "extended_memo"
end
ofx = OFX.new("spec/fixtures/bank_simple.ofx")
ofx.transactions.first.extended_memo
OFX.reset_config!  # restore defaults between tests

License

MIT