Developer Guide

NCPDP to JSON

The NCPDP Telecommunication Standard is the backbone of pharmacy claims in the US. It's also a nightmare to implement. Starlight converts it all to JSON.

The NCPDP Telecom format

The NCPDP Telecommunication Standard (version D.0) is a delimiter-based binary protocol used by virtually every pharmacy in the United States to submit claims to PBMs and insurance companies. It handles billions of transactions per year.

The format uses field separators (0x1C), group separators (0x1D), and segment identifiers to encode claim data. Numeric fields use signed overpunch encoding — a legacy format where the last digit of a number encodes both the digit and the sign (positive/negative).

Every integration team building pharmacy claims software must implement this protocol from scratch: parsing segment separators, decoding overpunch fields, managing payer-specific field requirements, and maintaining switch connectivity.

Before and after Starlight

Traditional NCPDP Telecom (raw)

 AM04 C2025862 C3TSAC C699995717 D2SAMPLE123456 D3002 D402 CA JOHN CB SMITH CC19900301 CD01 CM54321 E103 D7999000001234 D81 DE00000000000 DF28 DD28 DE20260101 DJ0 DB1234567890 DRSAMPLE PM5555555555

Starlight JSON

{
  "transaction_type": "B1",
  "patient": {
    "first_name": "JOHN",
    "last_name": "SMITH",
    "date_of_birth": "19900301",
    "gender": "M",
    "zip_code": "54321"
  },
  "insurance": {
    "bin_number": "999999",
    "pcn": "TEST",
    "group_id": "GRP999999",
    "cardholder_id": "SAMPLE123456"
  },
  "prescription": {
    "rx_number": "999000001234",
    "product_id": "00000000000",
    "quantity_dispensed": "28",
    "days_supply": "28"
  }
}