open-banking-io (Ruby)

Server-to-server client for open-banking.io. It authenticates with your API key and decrypts the zero-knowledge data envelopes locally with your exported private key — the service only ever returns ciphertext it cannot read.

gem install open-banking-io

require "open_banking_io"

# Load the credentials .json you exported from the app (API key + private key).
client = OpenBankingIO::Client.from_credentials("credentials.json")

client.get_accounts.each do |account|
  booked = account.balances.find { |b| b.type == "ITBD" }
  label = account.display_name || account.owner_name
  puts "#{label} #{account.iban}: #{booked&.amount} #{account.currency}"

  page = client.get_transactions(account.id, limit: 50)
  page.items.each do |t|
    puts "  #{t.booking_date}  #{t.creditor_name || t.debtor_name}  #{t.amount} #{t.currency}"
  end

  # Trigger an online sync (decrypts the account uid locally and posts it):
  client.sync(account.id)
end

Or construct it explicitly:

client = OpenBankingIO::Client.new(
  api_base_url: api_base_url,
  api_key: api_key,
  private_key_pkcs8: private_key_pkcs8
)

API

• get_accounts → Array<Account> — decrypts each account's envelope, display name and balances.
• get_transactions(account_id, from: nil, to: nil, limit: nil, offset: nil) → TransactionPage
• get_connections → Array<Connection>
• sync(account_id) → SyncResult — decrypts the account uid locally and posts it.
• sync_all → SyncAllResult — syncs every account that has an active session.

Amounts are exposed as BigDecimal. Models are immutable keyword-initialised Structs.

Every request sets connect/read timeouts (15s/60s) and a User-Agent: open-banking-io/ruby/<version> header.

Encryption

Envelopes use ECDH P-256 → HKDF-SHA256 → AES-256-GCM, implemented entirely with Ruby's OpenSSL standard library. Decryption requires the private key from your credentials bundle and happens fully in-process. See the repo README for the full scheme and the other language clients (.NET, Node, Python, Rust, Go, Java).

Development

bundle install
bundle exec rspec

MIT licensed.