Kurrent · Route
Call tracking. You pay the carrier direct.
Track, route and log every call — with the minutes and numbers on your own Telnyx account, at the carrier's own rates. Connect it once to sync your numbers and place orders; every SIP user and DID becomes a source you can route, log and watch. No markup on a single minute.
Kurrent, explained in 73 seconds.
The problem, the fix, and the numbers. Then bring us your bill.
What it costs
Half the software line of the call-tracking bill you pay today — you need $1,795 a month of spend to qualify. Carriage moves to your own Telnyx account at cost, and we take nothing on it.
| Software | half your current call-tracking bill, flat |
| Inbound minute — local number | as low as $0.0032 · your own Telnyx, at cost — requires Telnyx minimum spend |
| Inbound minute — toll-free | $0.015 |
| Outbound minute | $0.005 |
| Local number | $1.00/mo |
From the case files · Case 04
The Bill That Grows Faster
A call desk went from 50,000 minutes a month to 200,000 and did get a discount. 50 seconds.
$0.0250 / MIN$0.0032 / MIN
Built by Jordan Soblick, Thomas Coolidge and Rey Reyna, who ran the desks these bills land on. Meet the team →
Sources in, targets out
Every SIP user and DID is a source with its own routing. This is the shape of the real console. The values are samples, not live traffic.
| Source | Ingress | Status | Routes to |
|---|---|---|---|
| Campaign trunk | SIP | Active | +1 555 010 4477 |
| Intake line | Phone | Active | +1 555 010 8643 |
| Overflow | SIP | Active | +1 555 010 2291 |
Per-source limits and gates
Every source has its own rate limits and inbound gates, set per line. Same console, sample values.
| Control | Setting | What it does |
|---|---|---|
| Concurrent | 10 | Ceiling on simultaneous calls through this source |
| Invites/min | 300 | SIP invite rate cap per minute |
| Calls/sec | 5 | Burst cap on inbound call rate |
| Blacklist | on | Every inbound number is validated against your external API — a flagged caller triggers the action you configure |
| Validators | on | A chain of external API checks after the blacklist; every one must pass, and the first failure runs the global action |
| Pre-ping | on | Ask the destination whether it will accept the call before connecting — route on the answer |
| Whitelist TO | 1 number | Restrict inbound calls to listed destination numbers — leave empty to allow all |
| Webhook | on | Call events delivered in real time to your HTTP endpoint |
Screen the call before it rings.
Every inbound number runs your own checks before a target hears it. There is no markup per lookup, because the APIs are yours. Blacklist first. Then your validator chain. Then a pre-ping to the destination. Anything that fails runs the action you set instead of connecting the call.
| Stage | What runs | On failure |
|---|---|---|
| Blacklist | The FROM number is checked against your external API — litigator lists, DNC, your own suppression file | The configured action runs instead of the route |
| Validator APIs | A chain of external checks that runs after the blacklist — carrier/line-type dip, consent lookup, fraud score, anything with an HTTP endpoint. Every validator must pass (AND) | The first failure triggers the global action |
| Pre-ping | Ask the destination whether it will take this call, before the caller is connected — accept, reject or route elsewhere on the answer | Falls through to the next target in the ring tree |
Your keys, your vendors. Each check runs on your own API contract. KX21 runs the chain and never marks up a lookup. It is the same model as the rest of the platform.
What it does
Your own Telnyx
Connect your Telnyx account to sync phone numbers and place orders. The carrier bill stays yours.
SIP & DID sources
SIP users and phone numbers that can take traffic, each routed to its own target.
Number management
Buy and set up DIDs on your Telnyx account. Map each one to the source that should answer.
Call log
Every attempt, with from, to, status, length and ring time, tied to its source.
Logs & Kamailio
App logs plus raw SIP proxy logs. Enough to debug a route from end to end.
Webhooks & API
Webhooks, API keys and team access. Edge Snapshot saves the config as it was.
Validator API chain
Chain as many outside checks as you like, one per source. Each uses your vendor and your key. All must pass, and the first failure runs your action.
Pre-ping before transfer
Ask the destination if it wants the call before you connect it. Then route on the answer. No dead transfers, and no wasted buyer capacity.
Routing is where inbound rules get enforced. Check the caller in the IVR before an agent picks up. Run litigation scrubs. Look at carrier dips. Kill a bad DID the moment it shows. Our Contact.IO talk covers the whole stack: building a compliant TCPA process.
What call tracking costs you
Metered call tracking rolls the software and the carrier into one per-minute rate. So a fair test counts the carrier on both sides. Kurrent is a flat fee. The minutes bill to your own Telnyx account at your own rate, and we take nothing on them. See Kurrent priced against Ringba that way, line by line, or against TrackDrive's eleven separate meters.
Your minutes, both ways
Nothing is sent to us. The numbers stay in your browser.
Questions
- What is Kurrent?
- Kurrent is call tracking and SIP routing that runs on your own Telnyx account. Every SIP user and phone number becomes a source you can route, rate-limit, screen and log, with a call log, SIP logs, webhooks and an API. The minutes and numbers are billed to you by the carrier at its own rates.
- How much does Kurrent cost?
- Half the software line of the call-tracking bill you pay today, as one flat monthly fee. You need $1,795 a month of current spend to qualify. Carriage moves to your own Telnyx account at cost: inbound to a local number from $0.0032 a minute, inbound toll-free from $0.015, outbound from $0.005, local numbers from $1.00 a month and call recording at $0.002 a minute.
- Do I need my own Telnyx account?
- Yes. You connect it once and Kurrent syncs your numbers and can place orders for new ones. Telnyx bills you directly for minutes and numbers; KX21 never sees that invoice and takes nothing on it.
- Does Kurrent mark up minutes or numbers?
- No. There is no per-minute meter and no markup on a single minute or number. The only thing you pay KX21 is the flat software fee.
- How does Kurrent screen a call before it rings?
- In order: the caller's number is checked against your blacklist API, then a chain of validator APIs you choose, such as a line-type dip, consent lookup or fraud score, every one of which must pass, then a pre-ping asks the destination whether it will take the call. Any failure runs the action you configured instead of connecting the call. Each check uses your own API contract and is never marked up.
- What limits can I set per source?
- Concurrent calls, SIP invites per minute and calls per second, each set per source. A whitelist can restrict which destination numbers a source may reach.
- Can I get call events in real time?
- Yes. Subscribe a webhook to call events and they arrive at your endpoint as they happen. The call log and the SIP-level logs are also available in the console and over the API.
- How does Kurrent compare to Ringba or TrackDrive?
- Ringba publishes $147 and $297 plans plus $0.05 to $0.055 a minute and $2 to $4 a number. TrackDrive publishes eleven separate meters across six committed-use tiers. Kurrent meters none of it: one flat fee, with carriage at the carrier's own rate on your own account. The comparison pages price both line by line.
- What does 'bring us your bill' mean for call tracking?
- Send the invoice you pay today. It is sorted into carriage and software, reconciled to its own total, and priced on Kurrent with the carriage moved to Telnyx at cost. Most bills come back at half or less, and if yours does not, we say so.