CAQH CORE

Payers and clearinghouses take X12 over the connectivity rules of CAQH CORE: a SOAP envelope around the interchange, sent over TLS with a client certificate or credentials. A caqh_core destination does that for an X12 route, in real time (a 270, answered with the payer's 271) or as batch submissions (837 claims through the queue).

Real-time eligibility

Registration posts a 270 to the gateway and gets the payer's 271 back in the same request. The route is pass-through, so nothing is queued and the answer is the payer's own.

# Registration asks the payer about a patient's coverage: a 270 in, the payer's 271 back.
[[route]]
name = "eligibility"
mode = "passthrough"
format = "x12"
request_timeout = "20s"
passthrough = { ack_from = "response_body" }   # answer the sender with the payer's 271
source = { type = "http", listen = "0.0.0.0:8443", path = "/x12/eligibility", auth = { type = "api_key", keys = { registration = "${REGISTRATION_KEY}" } } }

[[route.destinations]]
name = "acme"
type = "caqh_core"
url = "https://core.acmehealth.example/CORE/RealTime"
sender_id = "NORTHSIDE"            # SenderID and ReceiverID, as the payer's connectivity guide gives them
receiver_id = "ACMEHEALTH"
tls = { client_cert = "/etc/hl7-edge-gateway/core-client.crt", client_key = "/etc/hl7-edge-gateway/core-client.key" }
auth = { type = "oauth2", token_url = "https://login.acmehealth.example/oauth2/token", client_id = "northside", client_secret = "${ACME_CORE_SECRET}" }

What the gateway sends, C4.0.0 with the interchange as an MTOM attachment:

POST /CORE/RealTime HTTP/1.1
Authorization: Bearer eyJ…
Content-Type: multipart/related; boundary="MIMEBoundary_…"; type="application/xop+xml";
  start="<root.…@hl7-edge-gateway>"; start-info="application/soap+xml"; action="RealTimeTransaction"

--MIMEBoundary_…
Content-Type: application/xop+xml; charset=UTF-8; type="application/soap+xml"

<soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope"><soapenv:Body>
  <ns1:COREEnvelopeRealTimeRequest xmlns:ns1="http://www.caqh.org/SOAP/WSDL/CORERuleC4.0.0.xsd">
    <PayloadType>X12_270_Request_005010X279A1</PayloadType>
    <ProcessingMode>RealTime</ProcessingMode>
    <PayloadID>9b0c6a0e-…</PayloadID>
    <TimeStamp>2026-10-26T14:30:05Z</TimeStamp>
    <SenderID>NORTHSIDE</SenderID>
    <ReceiverID>ACMEHEALTH</ReceiverID>
    <CORERuleVersion>C4.0.0</CORERuleVersion>
    <Payload><xop:Include href="cid:payload.…@hl7-edge-gateway" xmlns:xop="http://www.w3.org/2004/08/xop/include"/></Payload>
  </ns1:COREEnvelopeRealTimeRequest>
</soapenv:Body></soapenv:Envelope>
--MIMEBoundary_…
Content-Type: application/octet-stream
Content-ID: <payload.…@hl7-edge-gateway>

ISA*00*          *00*          *ZZ*NORTHSIDE      *ZZ*ACMEHEALTH     *…~
…

Batch claims

On a store-and-forward route, each interchange is a batch submission (BatchSubmitTransaction), with PayloadLength and a SHA-1 CheckSum of the payload. The billing system gets the gateway's 999 at once; the queue delivers in order and retries while the server is busy.

# Claims through the queue to the clearinghouse, as CORE batch submissions.
[[route.destinations]]
name = "clearinghouse"
type = "caqh_core"
url = "https://edi.clearinghouse.example/core"
sender_id = "NORTHSIDE"
receiver_id = "CLEARHOUSE"
processing_mode = "batch"          # the default on store-and-forward routes
tls = { client_cert = "/etc/hl7-edge-gateway/core-client.crt", client_key = "/etc/hl7-edge-gateway/core-client.key" }

Batch results

The server keeps what comes back from a batch for you to pick up: 999s for your submissions, 277CA claim acknowledgments and 835 remittances. A caqh_core source (0.8.1 or later) asks for them every poll_interval, for each PayloadType in retrieve, until the server has nothing left (X12_005010_Response_NoBatchResultsFile). Each file is taken in like any X12 interchange (checked, stored, filtered, transformed and delivered), and for a batch result the gateway's 999 goes back to the server, as CORE asks.

# 835 remittances and 277CA claim acknowledgments waiting on the clearinghouse's CORE server,
# picked up every 15 minutes and posted to the revenue system.
[[route]]
name = "remits"
mode = "store_and_forward"         # required: each result is stored before it is acknowledged
format = "x12"

[route.source]
type = "caqh_core"
url = "https://edi.clearinghouse.example/core"
sender_id = "NORTHSIDE"
receiver_id = "CLEARHOUSE"
retrieve = ["X12_835_Request_005010X221A1", "X12_277CA_Request_Batch_Results_005010X214E1_2"]
poll_interval = "15m"              # default 5m
# max_files = 100                  # per PayloadType and poll; the rest come next poll
# acknowledge = true               # send the gateway's 999 back for each result
tls = { client_cert = "/etc/hl7-edge-gateway/core-client.crt", client_key = "/etc/hl7-edge-gateway/core-client.key" }

[route.destination]
type = "http"
url = "https://revenue.northside.example/api/remits"

The source takes the same rule_version, transport, tls, auth, username and password as the destination. A file the server hands out again is caught as a duplicate: acknowledged again, delivered once. In a cluster one node at a time polls. hl7edge_core_retrievals_total counts by route and result (retrieved <PayloadType>, nothing waiting, acknowledged, failed).

Rule versions

# A server still on Phase II connectivity (CORE 2.2.0)
[[route.destinations]]
name = "regional-payer"
type = "caqh_core"
rule_version = "2.2.0"
transport = "soap"                 # SOAP with a WS-Security UsernameToken; or "mime" (HTTP MIME multipart)
url = "https://edi.regionalpayer.example/core"
sender_id = "NORTHSIDE"
receiver_id = "REGIONAL"
username = "northside"
password = "${REGIONAL_CORE_PASSWORD}"

payload_type is X12_<ST-01>_Request_<guide> unless you set it, such as X12_270_Request_005010X279A1; processing_mode is real_time on pass-through routes and batch on store-and-forward ones. headers adds static headers.

What the server's answer does

hl7edge_core_requests_total counts the answers by route, destination and ErrorCode (or the HTTP status or fault when there was no envelope).