Backwork
API Reference

Search drug formulary evidence

Search commercial pharmacy-benefit evidence from CVS Caremark, Express Scripts, and UnitedHealthcare / Optum Rx.

Endpoint: GET /api/v1/drugs/formulary

Availability: Live in production.

Authentication: API key in Authorization: Bearer <key> with the read scope.

Search commercial pharmacy-benefit evidence from CVS Caremark, Express Scripts, and UnitedHealthcare / Optum Rx. Records are informational; verify current coverage, utilization management, and member-specific benefits with the payer.

Parameters

  • q (query, required): Drug name or therapeutic category search query
  • payer (query): Optional payer/PBM source filter
  • limit (query): Maximum results per source

Example request

curl -X GET "https://backworkhealth.com/api/v1/drugs/formulary?q=metformin&payer=all" \
  -H "Authorization: Bearer $BACKWORK_API_KEY"

Example response (200)

{
  "success": true,
  "data": [
    {
      "source": "cvs_caremark",
      "payer_name": "string",
      "pbm_name": "string",
      "formulary_name": "string",
      "plan_year": 0,
      "effective_date": "string",
      "drug_name": "string",
      "matched_text": "string",
      "therapeutic_category": "string",
      "drug_class": "string",
      "tier": "string",
      "coverage_status": "string",
      "requirements": {
        "prior_authorization": true,
        "step_therapy": true,
        "quantity_limit": true,
        "specialty": true,
        "text": "string",
        "codes": [
          "string"
        ]
      },
      "alternatives": "string",
      "preferred_alternatives": "string",
      "source_url": "string",
      "source_page": 0
    }
  ],
  "meta": {
    "request_id": "string",
    "timestamp": "2026-01-15T10:30:00Z",
    "search": {
      "query": "string",
      "payer": "string"
    },
    "counts": {
      "cvs_caremark": 0,
      "express_scripts": 0,
      "uhc": 0,
      "total": 0
    },
    "limit_per_source": 0,
    "attributions": {
      "disclaimer": "string",
      "cpt": "string",
      "loinc": "string",
      "cms": "string",
      "payer_data": "string",
      "negotiated_rates": "string"
    },
    "disclaimer": "string"
  }
}
GET
/drugs/formulary

Authorization

bearerAuth
AuthorizationBearer <token>

API key in format: bwk_live_xxxxx. Keys issued before the rename (vrt_live_) remain valid. bwk_test_ keys work only on the sandbox.

In: header

Query Parameters

q*string

Drug name or therapeutic category search query

Length2 <= length <= 200
payer?string

Optional payer/PBM source filter

Default"all"

Value in

  • "all"
  • "cvs_caremark"
  • "express_scripts"
  • "uhc"
limit?number

Maximum results per source

Range1 <= value <= 100
Default25

Response Body

application/json

application/json

application/json

application/json

application/json

application/json

application/json

curl -X GET "https://example.com/drugs/formulary?q=metformin"
{  "success": true,  "data": [    {      "source": "cvs_caremark",      "payer_name": "string",      "pbm_name": "string",      "formulary_name": "string",      "plan_year": 0,      "effective_date": "string",      "drug_name": "string",      "matched_text": "string",      "therapeutic_category": "string",      "drug_class": "string",      "tier": "string",      "coverage_status": "string",      "requirements": {        "prior_authorization": true,        "step_therapy": true,        "quantity_limit": true,        "specialty": true,        "text": "string",        "codes": [          "string"        ]      },      "alternatives": "string",      "preferred_alternatives": "string",      "source_url": "string",      "source_page": 0    }  ],  "meta": {    "request_id": "string",    "timestamp": "2019-08-24T14:15:22Z",    "search": {      "query": "string",      "payer": "string"    },    "counts": {      "cvs_caremark": 0,      "express_scripts": 0,      "uhc": 0,      "total": 0    },    "limit_per_source": 0,    "attributions": {      "disclaimer": "string",      "cpt": "string",      "loinc": "string",      "cms": "string",      "payer_data": "string",      "negotiated_rates": "string"    },    "disclaimer": "string"  }}

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