Changelog

All notable changes to this project are documented here. The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[1.2.0] - 2026-07-07

USSD apps now have test and live modes. create_app responses expose id (UUID string), mode, test_secret (ussk_test_), live_secret (ussk_live_), is_live, and active in place of the single secret.
client.ussd.set_mode(app_id, mode) to switch an app between test and live, and client.ussd.rotate_secret(app_id, mode) to rotate the secret for a mode.
ExtensionRequiredError (402, extension_required), raised when switching an app to live mode before an extension has been purchased.

App and extension ids are UUID strings; every id parameter (update_app, delete_app, rent_extension's app_id, release_extension, session, and the new methods) is now typed str.
simulate now takes the app to target: simulate(app_id, session_id, msisdn, input="", new_session=False, service_code=None). service_code is optional and defaults to the shared short code server-side. Simulation always runs in the sandbox (test mode); an app you do not own returns 422 unknown_app.
Renting an extension draws from the dedicated USSD balance; on insufficient funds it now returns 402 insufficient_ussd_balance (mapped to InsufficientBalanceError).
Error mapping now honours the response error slug, so 402 responses resolve to InsufficientBalanceError or ExtensionRequiredError as appropriate.

USSD support via the client.ussd namespace: pricing, availability, apps, create_app, update_app, delete_app, extensions, rent_extension, release_extension, sessions, session, and simulate.
ConflictError (409), raised when renting an extension that is no longer available (extension_unavailable).

Error messages now fall back to the response body's error field when no message is present.

Initial release of the official Hellio Messaging Python SDK.
Hellio client with Bearer-token auth, configurable base URL and timeout, and environment-variable fallbacks (HELLIO_API_TOKEN, HELLIO_BASE_URL, HELLIO_DEFAULT_SENDER).
Methods: balance, pricing, sms, message, campaign, otp, verify_otp, verify, voice, voice_status, lookup, lookups, lookup_result, verify_email, webhooks, create_webhook, delete_webhook.
Recipient normalization (string, comma-separated string, or list).
Typed exception hierarchy mapped by HTTP status: HellioError, InvalidApiTokenError (401), InsufficientBalanceError (402), ValidationError (422), RateLimitError (429).
Injectable httpx.Client for testing.
Full type hints and a py.typed marker.