pip install telnyx

import os
from telnyx import Telnyx

client = Telnyx(
    api_key=os.environ.get("TELNYX_API_KEY"),  # This is the default and can be omitted
)

import telnyx

try:
    result = client.messages.send(to="+13125550001", from_="+13125550002", text="Hello")
except telnyx.APIConnectionError:
    print("Network error — check connectivity and retry")
except telnyx.RateLimitError:
    # 429: rate limited — wait and retry with exponential backoff
    import time
    time.sleep(1)  # Check Retry-After header for actual delay
except telnyx.APIStatusError as e:
    print(f"API error {e.status_code}: {e.message}")
    if e.status_code == 422:
        print("Validation error — check required fields and formats")

response = client.calls.actions.start_forking(
    call_control_id="550e8400-e29b-41d4-a716-446655440000",
)
print(response.data)

response = client.calls.actions.stop_forking(
    call_control_id="550e8400-e29b-41d4-a716-446655440000",
)
print(response.data)

response = client.calls.actions.start_streaming(
    call_control_id="550e8400-e29b-41d4-a716-446655440000",
    stream_url="wss://example.com/audio-stream",
)
print(response.data)

response = client.calls.actions.stop_streaming(
    call_control_id="550e8400-e29b-41d4-a716-446655440000",
)
print(response.data)

response = client.calls.actions.start_transcription(
    call_control_id="550e8400-e29b-41d4-a716-446655440000",
)
print(response.data)

response = client.calls.actions.stop_transcription(
    call_control_id="550e8400-e29b-41d4-a716-446655440000",
)
print(response.data)

# In your webhook handler (e.g., Flask — use raw body, not parsed JSON):
@app.route("/webhooks", methods=["POST"])
def handle_webhook():
    payload = request.get_data(as_text=True)  # raw body as string
    headers = dict(request.headers)
    try:
        event = client.webhooks.unwrap(payload, headers=headers)
    except Exception as e:
        print(f"Webhook verification failed: {e}")
        return "Invalid signature", 400
    # Signature valid — event is the parsed webhook payload
    print(f"Received event: {event.data.event_type}")
    return "OK", 200