“Pay As You Go” has become one of the least reliable phrases in wholesale voice. Almost everyone advertises it. Far fewer offer terms that behave like it once your first invoice arrives. These are the five things worth checking before you commit traffic.
1. How is a call actually measured?
This is the single biggest difference between providers, and it rarely appears in the headline rate. Per-second billing means a 14-second call costs you 14 seconds. Per-minute billing rounds that same call up to 60 seconds — you have just paid four times over.
The impact scales with how short your calls are. A business making long consultative calls barely notices. A dispatch operation, a delivery firm confirming drop-offs, or any outbound team leaving short voicemails will pay a substantial premium on rounded billing without ever seeing a rate increase.
Watch for two related clauses: minimum call duration (a floor applied regardless of actual length) and connection fees (a flat charge per attempt, which quietly punishes campaigns with low answer rates).
2. Is there a minimum spend hiding in the terms?
A genuine Pay As You Go account has no monthly commitment. If the contract mentions a minimum monthly spend, a committed volume, or a fee that applies when usage falls below a threshold, it is a contract with prepayment attached — not Pay As You Go.
This matters most for businesses with seasonal patterns. If your volumes halve over the summer, a minimum spend means paying for capacity you are not using, every year, forever.
3. What happens to unused credit?
Credit expiry is common and often buried. Some providers void a balance after 6 or 12 months of inactivity; others take a monthly maintenance fee from a dormant account. Neither is unreasonable if disclosed, but both change the economics if you top up in large increments.
Worth asking directlyDoes my credit expire, and is there any charge on a dormant account? A provider that answers plainly is telling you something useful about how the rest of the relationship will go.
4. How are rate changes communicated?
Wholesale termination rates genuinely do move — carriers adjust, regulations change, and destinations get re-rated. That is normal. What matters is notice.
Reasonable providers give advance notice in writing before a rate takes effect. Less reasonable ones update a rate table silently and let you discover it on the invoice. Ask what the notice period is and whether you are told by email or expected to check a portal.
5. What actually protects you from a runaway bill?
This is where prepaid genuinely shines and it deserves more credit than it gets. If your PBX is compromised and used for toll fraud, an attacker can only ever spend the credit sitting on the account. On a postpaid arrangement the same incident can generate a five-figure bill overnight.
That protection is real, but it is not a security strategy on its own. Prepaid limits the damage; it does not prevent the intrusion. Destination restrictions, balance alerts and a properly configured firewall are what stop it happening in the first place — we wrote about that in detail in how toll fraud actually happens.
A short checklist
- Billing increment — per second, or rounded to the minute?
- Minimum call duration or per-attempt connection fee?
- Monthly minimum spend, committed volume or contract term?
- Credit expiry, dormancy fees or account maintenance charges?
- Notice period for rate changes, and how you are notified?
- Spend caps and destination restrictions available?
If a provider will answer all six clearly and in writing, the commercial side is probably sound. If several answers are vague, the pricing on the front page is not the price you will pay.
VOIPNOX bills per second with no minimum spend and no contract.
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