VoIP Provider LRN

LRN Lookup for VoIP Providers.

Sub-10ms LRN dips for SIP routing accuracy. FreeSWITCH, OpenSIPS, and Kamailio compatible. NPAC-sourced data for correct carrier routing on every call.

Get API Access NowSee Integration Guide
<10ms
SIP Overhead
NPAC
Data Source
SIP
Native Integration
# FreeSWITCH ESL pre-route hook
call-incoming: DNIS=+16145550037
✓ lrn: "6145550037"  ocn: "6529"
✓ Route via: carrier-cl-ohio-01
✓ LRN dip overhead: 8ms

Infrastructure-Grade

LRN for Every VoIP Stack

Whether you run FreeSWITCH, Asterisk, OpenSIPS, or a proprietary switch — we integrate.

📡

SIP Routing via LRN

Route SIP calls based on LRN, not just DNIS. Essential for correctly routing to terminating carriers when numbers have been ported.

⚡

Sub-10ms SIP Overhead

Designed to fit within SIP call setup time budgets. Our API adds less than 10ms of overhead to pre-INVITE LRN lookups.

🔌

FreeSWITCH Compatible

Direct ESL module and REST module available for FreeSWITCH deployments. Drop into your dialplan with a single include.

🌐

OpenSIPS / Kamailio

REST client integration docs for OpenSIPS and Kamailio. LRN lookup before your routing logic using http_async module.

🏢

UCaaS Platform Ready

Multi-tenant API key support for UCaaS platforms serving multiple enterprise customers with separate billing.

📊

OCN & SPID Routing

Beyond LRN — access OCN and SPID data for carrier identification, intercarrier compensation, and bill-and-keep routing decisions.

Start Free — 1,000 Lookups Included

Developer-First

REST API — Works with Any SIP Stack

Request

POST https://api.sipsmart.io/v1/lrn/lookup
{
  "dnis": "+16145550037",
  "fields": ["lrn", "ocn", "spid", "ported"],
  "client_id": "voip-switch-01"
}

Response — <10ms

200 OK
{
  "dnis": "+16145550037",
  "lrn": "6145550037",
  "ocn": "6529",
  "spid": "6529A",
  "ported": true,
  "routing_hint": "cl-ohio-hub",
  "latency_ms": 7
}
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Simple, Predictable Pricing

No Surprises. Ever.

We charge less than legacy providers and publish our prices openly. No setup fees, no hidden costs, no annual lock-in required.

Starter
$0.0001
per lookup
  • ✓ Real-time LRN dip
  • ✓ Standard latency
  • ✓ HTTPS API
  • ✓ 1,000 free lookups
Best Value
Volume
$0.00005
per lookup (1M+/mo)
  • ✓ Real-time + batch
  • ✓ <10ms Ohio cluster
  • ✓ Dedicated endpoint
  • ✓ Priority SLA
Enterprise
Custom
flat-rate
  • ✓ DB replication
  • ✓ On-prem option
  • ✓ SLA guarantee
  • ✓ Dedicated support

🛡 Pricing Guarantee

We will match or beat any competitor's published price for equivalent LRN lookup volume. Contact us with a quote.

Get Started Free

FAQ

VoIP Provider LRN FAQ

Have another question? Email us at support@sipsmart.io

  • When a subscriber ports their number, the LRN changes. Without LRN lookup, your SIP routing sends calls to the wrong terminating carrier, causing failed completions. LRN-based routing ensures every call reaches the correct destination regardless of porting history.
  • We provide a dialplan snippet that fires an HTTP lookup against our API during call setup. The LRN is returned and used for outbound carrier selection via our LCRD module integration. Full integration guide included with API access.
  • We support both REST/HTTP and ENUM-based LRN lookup for legacy SIP switch integrations. ENUM responses are formatted per RFC 3761 with LRN and carrier NAPTR records included.

Accurate SIP Routing Starts with LRN

Sub-10ms dips, SIP-native integration, NPAC-sourced data. 1,000 free lookups.

Get API Access NowView Pricing

1,000 free lookups included • No credit card required • Instant provisioning