Production-grade Elixir client for the Column Bank API.

Column is a bank-as-a-service platform providing FDIC-insured accounts, KYC/KYB compliance, and every major US payment rail: ACH, Fedwire, SWIFT international wires, RTP/FedNow realtime payments, and checks.

Installation

Add column to your dependencies in mix.exs:

def deps do
  [
    {:column, "~> 0.1"}
  ]
end

Configuration

Set your Column API key in config/config.exs:

config :column, api_key: System.get_env("COLUMN_API_KEY")

For runtime configuration (e.g. config/runtime.exs):

config :column,
  api_key: System.get_env("COLUMN_API_KEY"),
  base_url: "https://api.column.com",  # default
  timeout: 30_000,
  max_retries: 3

Per-request config override (useful for multi-tenant setups):

config = %Column.Config{api_key: "live_abc123"}
Column.BankAccounts.list(config: config)

Environments

• Sandbox: Use test_... prefixed API keys. Call Column.Simulation.* to trigger synthetic network events.
• Production: Use live_... prefixed API keys.

Module map

Error handling

All functions return {:ok, map()} or {:error, %Column.Error{}}:

case Column.BankAccounts.get("bacc_missing") do
  {:ok, account} ->
    account
  {:error, %Column.Error{type: :api_error, status: 404}} ->
    {:error, :not_found}
  {:error, %Column.Error{type: :network_error} = err} ->
    Logger.error("Column network error: #{err.message}")
    {:error, :unavailable}
end

Pagination

All list functions support cursor pagination. Use Column.Pagination.stream/2 to consume pages lazily as a Stream:

Column.Pagination.stream(&Column.Transfers.list/1, limit: 100)
|> Stream.filter(fn transfer -> transfer["status"] == "SETTLED" end)
|> Enum.to_list()

Idempotency

All POST requests automatically generate and attach an Idempotency-Key header. Supply your own to control retry behaviour:

Column.ACH.create(%{...}, idempotency_key: "my-unique-key")

Webhook signature verification

Column.Webhooks.verify_signature(raw_body, signature_header, webhook_secret)
# => :ok | :error