MakkQ: Thanks for clarifying my earlier questions. I have just three follow-up questions:
1. Additional Email Pricing: If I exceed the 25,000 emails/month limit, what would be the estimated monthly cost for additional sending capacity of 25,000, 50,000, or 100,000 emails? Will AppSumo LTD customers receive any special pricing for additional email volume?
2. Automatic Retry Details: For temporary email delivery failures, how many automatic retry attempts does Utobo make, and what is the retry interval between attempts?
3. Idempotency Details: How long does an Idempotency-Key remain valid? If I retry the same API request using the same Idempotency-Key, will Utobo return the same Message ID without sending a duplicate email?
Thanks again for your help!
Raj_utobo
Oct 30, 2026A: Hey! You are welcome. Thanks for asking additional questions.
Additional email: beyond your 25,000/month, extra sending is normally ~$0.90 per 1,000. As an AppSumo customer you get 40% off — about $0.54 per 1,000:
+25k ≈ $13.50/mo
+50k ≈ $27/mo
+100k ≈ $54/mo
Retries: temporary failures are retried automatically by our sending infrastructure — it backs off over several hours until it delivers or hard-fails; transient API errors return a Retry-After so you can retry safely.
Idempotency: keys are valid 24 hours. Same key + same request → the same send ID, no duplicate. Same key + a different request → 409, so a stale key can’t silently swap one email for another.