Integrate with the Arcadia (Arc) API to submit a Green Button authorization and retrieve structured utility bill data for a customer account

Steps

1. Obtain API credentials from Arcadia by registering as a developer at arcadia.com; authenticate using OAuth 2.0 client_credentials flow against the Arcadia authorization server to obtain a bearer token.
2. Create a credential submission for the customer by POSTing to the /utility-credentials endpoint with the customer's utility username, password (via the Arcadia secure credential submission flow — never log or store the plaintext password), and the utility's identifier (arcadia-assigned utility code).
3. Poll the credential status endpoint (GET /utility-credentials/{id}) until the status transitions from 'pending' to 'connected' or 'error'; 'connected' indicates Arcadia has successfully authenticated with the utility on the customer's behalf and data collection has begun.
4. Once connected, retrieve bill statements via GET /accounts/{account_id}/statements which returns a list of bill statement objects with billing period start/end dates, total charges, and a breakdown by charge component (energy, demand, taxes, fees).
5. For interval usage data, call GET /accounts/{account_id}/intervals?start={date}&end={date} to retrieve time-series meter data; parse the response array of {start, end, kwh} objects and apply the ReadingType metadata to confirm units and accumulation behavior.
6. Handle credential expiration: utility websites change passwords and session requirements; implement a webhook or polling loop on the credential status endpoint to detect 'error' states and trigger a re-authorization flow for the customer when credentials become invalid.