Customers and the Python SDK

• Customers (/v1/customers): for platforms sending on behalf of other businesses. Assign numbers to a customer and its messages, verifications, events and webhooks carry customer_id; GET /v1/customers/{id}/usage reports per-customer usage by day. See Customers.
• customer_id on POST /v1/messages, POST /v1/verify, POST /v1/numbers, new PATCH /v1/numbers/{number}, and filters on GET /v1/messages and GET /v1/numbers. Numbers now always include customer_id (null when unassigned).
• Python SDK: pip install joinsimplesms. No dependencies, typed, retries, idempotent sends, webhook verification.
• Node SDK: consent and customers resources, listAll() iterators, and verifyWebhook().