> ## Documentation Index > Fetch the complete documentation index at: https://docs.haau3.com/llms.txt > Use this file to discover all available pages before exploring further. # Check providers against a plan's network > FHIR instance-level operation `$in-network` on InsurancePlan: for each NPI, whether the CMS National Provider Directory lists the provider in a network this plan names, for the plan's year. The answer is a `Parameters` resource: the `plan`; the directory's `data-date`; one `network` per network checked, with the number of organizations it lists; a `reason` when there is no network data; a Marketplace plan's own `directory`; one `provider` per NPI, in the order sent, with its `status` (`in-network`, `not-found`, `not-in-directory` or `no-network-data`) and, when listed, `evidence` references to the directory's records on this base; then a `source` when the directory was asked. `not-found` never means out of network: the directory's network data is incomplete, and a listing is not a statement of a contract. All or nothing: a lookup that fails fails the whole answer. GET only. Defined by the haau3 implementation guide (`https://haau3.com/fhir/OperationDefinition/InsurancePlan-in-network`). ## OpenAPI ````yaml /api-reference/openapi.json get /v1/fhir/r4/InsurancePlan/{id}/$in-network openapi: 3.1.0 info: title: haau3 Platform API version: 1.0.0-preview.4 description: >- The haau3 platform API is in preview: it may change as we build, usually to add features or improve performance. Endpoints require an API key, sent as `Authorization: Bearer `. Requests without a valid key return 401. Create a key in the dashboard at https://platform.haau3.com; a new organization starts on the free Developer plan. From 2026-11-01 a request past one of its plan's limits (requests a minute on every plan, requests a month on Developer) returns 429 with `Retry-After`. Every error under `/v1/fhir` is a FHIR `OperationOutcome` and every other error an RFC 9457 problem; https://docs.haau3.com/errors lists every status, whether to retry it, and what a method a path does not take answers. servers: - url: https://api.haau3.com description: Production security: - bearerAuth: [] tags: - name: Scheduling description: 'Provider availability (SMART Scheduling Links): slots and publishers.' - name: FHIR base description: >- What the FHIR R4 base at `/v1/fhir/r4` answers for every service on it: the `CapabilityStatement` that lists them all, and batch Bundles that carry several requests to any of them in one round trip. - name: Terminology description: >- FHIR terminology operations over the code systems listed in TerminologyCapabilities. Some are resolved from their own source when you ask; others are held here at a named release, which that resource also names. - name: Provider directory description: >- CMS's National Provider Directory as FHIR R4: practitioners and their roles, organizations, payers and insurance networks, network membership, healthcare services, locations and endpoints. Every parameter the service serves is declared here, and any other is refused by name rather than ignored. - name: Questionnaires description: >- FHIR Questionnaire, served as its source publishes it. This service holds copies of a curated set and reaches any other questionnaire its source publishes by canonical URL, as well as forms published at their own address under places this service is set up to reach. Read one by id, and build the QuestionnaireResponse in your own application. - name: Plan Benefits description: >- FHIR InsurancePlan: what a Medicare Advantage or ACA Marketplace plan covers and what a member pays, read from the files CMS publishes. Every plan names the CMS release it was read from. Read a plan by its id, or search by identifier, name, state or county, and check whether the CMS National Provider Directory lists providers in a plan's network. - name: MedList description: >- One reconciled medication list from one patient's FHIR medication records, as US Core MedicationRequests with a Provenance for each. This operation receives patient data, so send it only under an executed agreement. paths: /v1/fhir/r4/InsurancePlan/{id}/$in-network: get: tags: - Plan Benefits summary: Check providers against a plan's network description: >- FHIR instance-level operation `$in-network` on InsurancePlan: for each NPI, whether the CMS National Provider Directory lists the provider in a network this plan names, for the plan's year. The answer is a `Parameters` resource: the `plan`; the directory's `data-date`; one `network` per network checked, with the number of organizations it lists; a `reason` when there is no network data; a Marketplace plan's own `directory`; one `provider` per NPI, in the order sent, with its `status` (`in-network`, `not-found`, `not-in-directory` or `no-network-data`) and, when listed, `evidence` references to the directory's records on this base; then a `source` when the directory was asked. `not-found` never means out of network: the directory's network data is incomplete, and a listing is not a statement of a contract. All or nothing: a lookup that fails fails the whole answer. GET only. Defined by the haau3 implementation guide (`https://haau3.com/fhir/OperationDefinition/InsurancePlan-in-network`). operationId: checkInsurancePlanNetwork parameters: - name: id in: path required: true schema: type: string pattern: ^[A-Za-z0-9\-.]{1,64}$ description: 'The plan''s id: `H2406-013-000` or `19898FL0340001-01`.' example: H3359-038-000 - name: npi in: query required: true style: form explode: true description: >- Up to 20 NPIs, ten digits each, as repeated `npi` parameters or separated by commas: `npi=1992700001&npi=1992700002` or `npi=1992700001,1992700002`. Duplicates count once. schema: minItems: 1 maxItems: 20 type: array items: type: string pattern: ^[0-9]{10}(,[0-9]{10})*$ example: - '1518929058' - '1992700001' - $ref: '#/components/parameters/XRequestId' responses: '200': description: A `Parameters` resource with each NPI's status, in the order sent. content: application/fhir+json: schema: $ref: '#/components/schemas/Parameters' examples: Two providers checked against a plan's network: summary: Two providers checked against a plan's network value: resourceType: Parameters parameter: - name: plan valueReference: reference: InsurancePlan/H3359-038-000 - name: data-date valueDate: '2026-10-14' - name: network part: - name: network valueReference: reference: >- Organization/Organization-ed682d9f-98da-4ada-a081-04b4f80fe9f3 display: Healthfirst Medicare Network H3359 - name: organizations-listed valueInteger: 0 - name: provider part: - name: npi valueIdentifier: system: http://hl7.org/fhir/sid/us-npi value: '1518929058' - name: status valueCoding: system: >- https://haau3.com/fhir/CodeSystem/plan-benefits-network-status code: in-network display: In network - name: evidence valueReference: reference: >- PractitionerRole/PractitionerRole-0000099c-a432-43eb-a399-61a936d5cc60 - name: provider part: - name: npi valueIdentifier: system: http://hl7.org/fhir/sid/us-npi value: '1992700001' - name: status valueCoding: system: >- https://haau3.com/fhir/CodeSystem/plan-benefits-network-status code: not-in-directory display: Not in the directory - name: source valueString: >- CMS National Provider Directory: https://directory.cms.gov/fhir headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' '400': description: >- A missing `npi`, an NPI that is not ten digits, more than 20 NPIs, or another parameter, named. content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' '401': $ref: '#/components/responses/FhirUnauthorized' '404': description: >- No plan with that id is in the releases being served, or the plan is held but is not a medical plan. The `OperationOutcome` says which. content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' '406': $ref: '#/components/responses/FhirNotAcceptable' '429': $ref: '#/components/responses/FhirTooManyRequests' '500': $ref: '#/components/responses/FhirServerError' '502': description: >- The plan store could not be read, or the directory failed a lookup or answered in a way that could not be read with confidence. No answer is given: this is never reported as a provider not found. content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' '503': description: >- No release of the plan files is being served for the plan's program, or the directory is rate limiting requests (with `Retry-After`). No answer is given. It is also the answer when the API key could not be checked just now, with `Retry-After`. content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: Retry-After: description: >- Sent when waiting will help: the API key could not be checked just now, or the source behind this service is rate limiting requests. How many seconds to wait before sending the request again. schema: type: integer minimum: 0 X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' '504': description: >- The plan store or the directory did not answer within the operation's time. No answer is given, never a partial one. content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' x-codeSamples: - lang: bash label: cURL source: > curl "https://api.haau3.com/v1/fhir/r4/InsurancePlan/H3359-038-000/\$in-network?npi=1518929058&npi=1992700001" \ -H "Authorization: Bearer $HAAU3_API_KEY" - lang: typescript label: TypeScript source: > import { Haau3 } from "@haau3/sdk"; const haau3 = new Haau3(); // reads HAAU3_API_KEY const parameters = await haau3.checkInsurancePlanNetwork("H3359-038-000", { npi: ["1518929058", "1992700001"], }); for (const parameter of parameters.parameter ?? []) console.log(parameter.name); - lang: python label: Python source: > from haau3 import Haau3 client = Haau3() # reads HAAU3_API_KEY parameters = client.check_insurance_plan_network("H3359-038-000", npi=["1518929058", "1992700001"]) for parameter in parameters.get("parameter", []): print(parameter.get("name")) - lang: go label: Go source: "package main\n\nimport (\n\t\"context\"\n\t\"fmt\"\n\t\"log\"\n\n\t\"github.com/haau3/haau3-go\"\n)\n\nfunc main() {\n\tctx := context.Background()\n\tclient, err := haau3.NewClient() // reads HAAU3_API_KEY\n\tif err != nil {\n\t\tlog.Fatal(err)\n\t}\n\tparameters, err := client.CheckInsurancePlanNetwork(ctx, \"H3359-038-000\", haau3.CheckInsurancePlanNetworkParams{NPI: []string{\"1518929058\", \"1992700001\"}})\n\tif err != nil {\n\t\tlog.Fatal(err)\n\t}\n\tfor _, parameter := range parameters.Parameter {\n\t\tif parameter.Name != nil {\n\t\t\tfmt.Println(*parameter.Name)\n\t\t}\n\t}\n}\n" components: parameters: XRequestId: name: X-Request-Id in: header required: false schema: type: string format: uuid description: >- An id of your own for this request, as a UUID. It comes back in the `X-Correlation-Id` header and is kept with haau3's record of the request. Any value that is not a UUID is ignored. See https://docs.haau3.com/errors#request-ids. schemas: Parameters: type: object description: A FHIR R4 [Parameters](https://hl7.org/fhir/R4/parameters.html). properties: resourceType: type: string const: Parameters parameter: type: array items: type: object additionalProperties: true required: - resourceType additionalProperties: true OperationOutcome: type: object description: >- A FHIR R4 [OperationOutcome](https://hl7.org/fhir/R4/operationoutcome.html). properties: resourceType: type: string const: OperationOutcome issue: type: array items: type: object properties: severity: type: string enum: - fatal - error - warning - information code: type: string details: type: object properties: text: type: string additionalProperties: true diagnostics: type: string expression: type: array items: type: string required: - severity - code additionalProperties: true required: - resourceType - issue headers: XRequestId: description: >- The id haau3 gave this request, a UUID, on every response. Quote it in a question about the response. A problem carries the same id as its `instance`. schema: type: string format: uuid XCorrelationId: description: The `X-Request-Id` you sent, when it was a UUID. schema: type: string format: uuid responses: FhirUnauthorized: description: Missing or invalid API key. content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: WWW-Authenticate: description: >- The scheme to authenticate with: `Bearer realm="api.haau3.com"`, with `error="invalid_token"` when a key was sent and not recognised. schema: type: string X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' FhirNotAcceptable: description: >- The request asked for a format other than JSON (`Accept` or `_format`), or for a FHIR release this endpoint does not serve (the `fhirVersion` media-type parameter). content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' FhirTooManyRequests: description: >- A limit of the organization's plan was reached: its requests a minute, or the Developer plan's requests a month. Send the request again after `Retry-After`, which for the monthly limit runs to the 1st of the next month (UTC). content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: Retry-After: description: How many seconds to wait before sending the request again. schema: type: integer minimum: 0 X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' FhirServerError: description: The server failed to process this request. content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' securitySchemes: bearerAuth: type: http scheme: bearer description: >- Your platform API key (`haau3_sk_…`), sent as `Authorization: Bearer `. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.