Pistonlog sends SMS via Twilio. Each text costs one SMS credit from your garage's balance, deducted at the moment the SMS is dispatched.
What costs a credit
| Action | Credits |
|---|---|
| A reminder SMS | 1 |
| A one-off reminder SMS | 1 |
| A payment link sent via SMS | 1 |
| A review request sent via SMS | 1 |
| An appointment confirmation SMS | 1 |
| Email (any kind) | 0 |
There's no "long-message" multiplier — one SMS is one credit, regardless of body length (within Twilio's normal 160-char or multipart envelope, which Pistonlog handles for you).
Topping up
Buy SMS credits from Settings → SMS Credits. Credits don't expire. You can see your current balance in the sidebar of the Reminders area.
What happens if you run out
If your balance hits zero mid-day, the next SMS attempt will fail and be logged in Reminder logs as insufficient_credits. Email reminders keep firing normally — they don't draw from this balance.
Why credits
Twilio charges per-message at carrier-set rates. Credits are how those costs land back on the garage's account without us reconciling Twilio bills in real time.