How to buy wholesale SIP termination
A technical buyer's checklist. What to test, what to ask, what to reject out of hand.
The mistakes most buyers make
The first quote you get will almost always be a blended per-minute rate. That's the red flag that tells you the rest of the conversation is theatre. A carrier who actually owns their routes has a landline rate and a mobile rate for every country they cover — usually a 3–5× gap between the two — plus a premium rate for satellite and toll endpoints. A single blended number hides the expensive destinations inside the cheap ones, and the bill that shows up next month is routinely 30–60% higher than the quoted rate suggested. Ask for the full deck as JSON or CSV on day one. Not a PDF, not a sales deck — the actual data. If the vendor treats that request as unusual, you already have your answer. Every serious carrier has this file ready to email without a NDA.
What to test during POC
Run a 24-hour burst at your peak campaign CPS through a test DID pool of at least 20 numbers. Measure four things: Answer-Seizure Ratio (ASR), Post-Dial Delay (PDD) at both mean and p95, post-answer silence on the first 3 seconds, and call-duration distribution. A carrier worth considering hits ≥65% ASR and ≤2.0s mean PDD on US domestic routes; below those numbers you're looking at a bad interconnect somewhere in the path. Include a 15-minute burst at 3–5× your normal CPS to expose capacity issues — many CPaaS vendors silently throttle above their plan cap and will simply drop calls rather than tell you. Record CDRs and keep them; if the vendor's portal CDR doesn't match yours, that tells you whether they're billing you honestly.
The five questions to ask every vendor
These five questions take ten minutes on a sales call and eliminate most of the market. One: what OCN do you sign STIR/SHAKEN under, and is it yours or are you borrowing it from an upstream? Two: what attestation level do you sign at on US/CA domestic, and will you show the SIP Identity headers from a sample call? Three: are there per-CPS fees, per-channel fees, or burst surcharges on top of the per-minute rate? Four: what's the notice period on rate-card changes, and is it written into the MSA? Five: can my existing DIDs stay on their current OCNs via BYOC, or do I have to port into your numbering plan to use the service? Any evasive answer on any of the five is a reason to end the call.
Red flags you should walk away from
Verbal-only rates, or rates that get emailed as an image. Enterprise-tier pricing gates that require a committed-use minimum just to see the real number. Contract minimums longer than 90 days for voice termination — modern carrier contracts are month-to-month. STIR/SHAKEN signed at B-level or gateway-attested but described on calls as "fully signed." Refusal to run a paid POC, or a POC with a hard cap of 100 minutes. Support routed through a chat widget with no NOC phone number. CDR delivered as an FTP dump once a day instead of via WebSocket or REST. Any vendor who says "we don't publish rates because every customer is different" is telling you the retail rate is punitive and the real rate is whatever you can negotiate. These signals are individually survivable; stacked three-or-more, they predict a painful 12 months.
What good looks like
The minimum bar for a serious 2026 carrier is a published rate deck covering 150+ destinations with a landline and mobile column for each, updated quarterly with a 30-day notice window on changes. They own the OCNs their traffic signs under — verifiable in the FCC's Robocall Mitigation Database — and sign at A-level on every eligible US/CA call by default. They offer IP-auth, digest, and TLS mutual-cert on the same trunk without forcing a choice. CDR ships as a WebSocket push stream with per-call webhooks as a fallback. The MSA is sendable on day one, templates for LOA and porting paperwork are in the customer portal. The NOC has a phone number that rings a human 24/7, and severity-1 tickets get first response in under 15 minutes. If a vendor can match every line of this list, you are talking to a real carrier. Most can't.
Test us on your real traffic.
Send a CDR export — we'll price you off the actual pattern, not a spreadsheet guess.