LRN Lookup API

Real-Time LRN Lookup API — Sub-10ms Response.

Carrier-grade LRN dips powered by direct NPAC connectivity. Automated setup in minutes. Predictable per-lookup pricing with no platform fees.

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<10ms
P99 Latency
NPAC
Direct Source
Instant
API Provisioning
curl -X POST api.sipsmart.io/v1/lrn/lookup \
  -d '{"number": "+16145550037"}'
✓ lrn: "6145550037"  ocn: "6529"
✓ ported: true  rate_center: "COLUMBUS"
✓ latency: 7ms

Infrastructure-Grade

Why Carriers Choose SIPSmart LRN API

Purpose-built for VoIP carriers, call centers, and telecom developers who need accurate, fast LRN data at production scale.

⚡

Sub-10ms Latency

Distributed U.S. replication infrastructure delivers P99 response times under 10ms — the lowest in the industry for LRN dips nationwide.

🤖

Automated Setup

API keys are provisioned instantly after registration. No sales calls, no paperwork. Your first LRN dip can happen in under 5 minutes.

🛡

Pricing Guarantee

We'll match or beat any competitor's published LRN lookup price. Our pricing is transparent and published — no hidden fees.

🏗

NPAC-Sourced Data

All LRN data is sourced directly from NPAC via our carrier-grade connections. No third-party resellers, no stale cached results.

🔄

Real-Time Portability

Detect ported numbers instantly. Our database is continuously synchronized with NPAC change feeds for millisecond-fresh data.

📈

High-Volume Ready

Multi-node Redis caching layer handles millions of dips per hour. No throttling, no queue delays at high call volumes.

Start Free — 1,000 Lookups Included

Developer-First

Simple REST API — No SDK Required

Request

POST https://api.sipsmart.io/v1/lrn/lookup
{
  "number": "+16145550037",
  "fields": ["lrn", "ocn", "spid", "rate_center", "lata"]
}

Response — <10ms

200 OK
{
  "number": "+16145550037",
  "lrn": "6145550037",
  "ocn": "6529",
  "spid": "6529A",
  "rate_center": "COLUMBUS",
  "lata": "330",
  "ported": true,
  "latency_ms": 7
}
cURLPythonNode.jsGoPHPRuby

Infrastructure

Multi-Region LRN Replication Infrastructure

Our LRN database is replicated across distributed U.S. regions to minimize lookup latency and maximize reliability. New regional endpoints are deployed dynamically based on customer demand, ensuring consistently low response times nationwide.

🌐

Distributed U.S. Endpoints

Replication nodes distributed across U.S. regions to serve nationally distributed traffic without cross-country latency penalties.

🧠

Intelligent Regional Routing

Requests are automatically routed to the nearest available replication node. Your queries never travel farther than necessary.

🔄

Automatic Failover

If a regional node becomes unavailable, queries instantly failover to the next nearest node. No manual intervention. No downtime.

📈

Horizontally Scalable

New replication nodes are provisioned based on geographic demand. As your traffic grows or spreads, the infrastructure scales with it.

⚡

Sub-10ms Target Response Time

Distributed architecture keeps query paths short. Sub-10ms response times across CONUS traffic patterns.

🔒

NPAC-Sourced at Every Node

All regional nodes replicate from NPAC-direct sources — not secondary resellers. Data freshness is consistent across all regions.

Learn more about our distributed infrastructure →

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

Full REST API Reference

Complete endpoint docs, response schema, error codes, rate limits, and code examples.

View API Reference →

FAQ

Frequently Asked Questions

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

  • An LRN (Location Routing Number) Lookup API queries the NPAC database to determine where a telephone number is currently routed — especially important for ported numbers. It returns the LRN, OCN, SPID, rate center, LATA, and porting status in a single API call.
  • Our distributed U.S. replication infrastructure delivers sub-10ms P99 response times nationwide. This is achieved through a multi-node Redis caching layer backed by direct NPAC connectivity — not a third-party reseller chain.
  • Yes. New accounts get 1,000 free LRN lookups with no credit card required. Start building in minutes.
  • Standard fields include: lrn, ocn, spid, rate_center, lata, ported, line_type, andlatency_ms. Enterprise accounts can request extended fields.
  • Yes. Our batch endpoint accepts up to 10,000 numbers per request and returns results in bulk. Ideal for list scrubbing and pre-dial verification workflows.

Ready for the Fastest LRN Lookup API?

Start with 1,000 free lookups. Automated provisioning, no sales calls required.

Get API Access NowView Pricing

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