API reference

request

curl -X POST https://denial7.com/api/v1/scrub \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: scrub-demo-1" \
  -d '{"dateOfService":"2026-07-01","lines":[{"code":"80053","modifiers":[],"units":1},{"code":"80048","modifiers":[],"units":1}]}'

response 200

{
  "data": {
    "input": {
      "dateOfService": "2026-07-01",
      "payerSlug": null,
      "lines": [
        {
          "code": "80053",
          "modifiers": [],
          "units": 1
        },
        {
          "code": "80048",
          "modifiers": [],
          "units": 1
        }
      ]
    },
    "editQuarter": "2026 Q3",
    "datasetQuarter": "2026 Q3",
    "findings": [
      {
        "kind": "ptp",
        "status": "fail",
        "lineIndexes": [
          0,
          1
        ],
        "codes": [
          "80053",
          "80048"
        ],
        "summary": "80048 is bundled into 80053 and no modifier can unbundle it",
        "rule": "PTP edit with modifier indicator 0. CMS rationale: CPT Manual or CMS manual coding instruction. Indicator 0 means no modifier is permitted to bypass this edit under any circumstances.",
        "remedy": "Remove 80048 from this claim, or bill 80048 alone on a date of service where 80053 is not billed. Appending a 59 or X modifier here would be an incorrect use of the modifier.",
        "citation": {
          "source": "CMS Medicare NCCI Procedure to Procedure Edits, Practitioner Services",
          "url": "https://www.cms.gov/medicare/coding-billing/national-correct-coding-initiative-ncci-edits/medicare-ncci-procedure-procedure-ptp-edits",
          "quarter": "2026 Q3",
          "retrievedAt": "2026-07-18",
          "confidence": "verified"
        }
      },
      {
        "kind": "mue",
        "status": "pass",
        "lineIndexes": [
          0
        ],
        "codes": [
          "80053"
        ],
        "summary": "80053: 1 unit is within the MUE of 1",
        "rule": "MUE 1, adjudication indicator MAI 3. Date of service edit, clinical. Units above this limit are unlikely but not impossible. A higher count can be allowed on appeal when the medical record supports it.",
        "remedy": "",
        "citation": {
          "source": "CMS Medicare NCCI Medically Unlikely Edits, Practitioner Services",
          "url": "https://www.cms.gov/medicare/coding-billing/national-correct-coding-initiative-ncci-edits/medicare-ncci-medically-unlikely-edits",
          "quarter": "2026 Q3",
          "retrievedAt": "2026-07-18",
          "confidence": "verified"
        }
      },
      {
        "kind": "mue",
        "status": "pass",
        "lineIndexes": [
          1
        ],
        "codes": [
          "80048"
        ],
        "summary": "80048: 1 unit is within the MUE of 2",
        "rule": "MUE 2, adjudication indicator MAI 3. Date of service edit, clinical. Units above this limit are unlikely but not impossible. A higher count can be allowed on appeal when the medical record supports it.",
        "remedy": "",
        "citation": {
          "source": "CMS Medicare NCCI Medically Unlikely Edits, Practitioner Services",
          "url": "https://www.cms.gov/medicare/coding-billing/national-correct-coding-initiative-ncci-edits/medicare-ncci-medically-unlikely-edits",
          "quarter": "2026 Q3",
          "retrievedAt": "2026-07-18",
          "confidence": "verified"
        }
      }
    ],
    "summary": {
      "total": 3,
      "failures": 1,
      "bypassed": 0,
      "noData": 0,
      "clean": false
    },
    "coverage": {
      "ptpPairsLoaded": 40009,
      "mueCodesLoaded": 15162,
      "note": "Checked against 40009 PTP pairs and 15162 MUE values curated from the published CMS 2026 Q3 files. This is a subset of the full CMS files. Codes marked no data were not checked and may still be subject to an edit. PTP edits carry their own effective and deletion dates, so a date of service in an earlier quarter is checked against the edit that was genuinely in force then. The MUE table carries no dates, so it is only applied to a date of service inside the quarter we hold."
    }
  },
  "request_id": "req_2f9c41a7b0e84d15",
  "disclaimer": "Denial7 provides billing and administrative guidance based on published CMS and X12 sources. It is not medical advice, not a coverage determination, and not a guarantee of payment. NCCI and MUE edits are republished quarterly and payer policies vary by contract. Always confirm against the payer's own current policy before submitting or appealing.",
  "attribution": "Data from Denial7 (https://denial7.com): CMS NCCI/MUE edits and X12 CARC/RARC codes, cited by source and confidence. Free responses require this attribution."
}

request

curl "https://denial7.com/api/v1/denial?carc=CO-45&rarc=N290&payer=medicare"

response 200

{
  "data": {
    "found": true,
    "group": {
      "code": "CO",
      "meaning": "Contractual Obligation. The provider is responsible and the amount cannot be billed to the patient."
    },
    "carc": {
      "code": "45",
      "commonGroups": [
        "CO"
      ],
      "title": "Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.",
      "plainMeaning": "The payer is telling you the billed charge is higher than the amount their fee schedule or contract allows for this service. The difference between what you billed and what the payer allows becomes a contractual write off, not something you can bill the patient for when an in network contract is in place.",
      "whyItFires": [
        "Billed charge exceeds the payer's fee schedule or contracted rate for the CPT/HCPCS code",
        "No modifier or documentation was included that could justify an exception to the fee schedule",
        "Fee schedule updated on the payer side (annual CMS or payer update) and the practice's charge master was not"
      ],
      "correctiveActions": [
        {
          "step": "Verify the contract rate",
          "detail": "Pull the current fee schedule or contract rate sheet for this payer and CPT code and confirm the allowed amount matches what was paid."
        },
        {
          "step": "Write off per contract",
          "detail": "If the allowed amount is correct per contract, adjust off the difference. This is a standard contractual adjustment, not an error."
        },
        {
          "step": "Check for a fee schedule update lag",
          "detail": "If the payer recently updated its fee schedule, confirm the correct effective date was applied to this date of service."
        }
      ],
      "appealWorthiness": "low",
      "appealNote": "Appeal only if you can show the payer used the wrong fee schedule, wrong contract year, or the code is not actually subject to that schedule. Otherwise this is a routine contractual write off and not appealable.",
      "relatedRarc": [],
      "sourceUrl": "https://x12.org/codes/claim-adjustment-reason-codes",
      "confidence": "verified"
    },
    "rarc": [
      {
        "code": "N290",
        "type": "informational",
        "title": "Missing/incomplete/invalid rendering provider primary identifier",
        "plainMeaning": "The claim is missing the NPI of the provider who actually performed the service, or the rendering provider NPI submitted does not match an enrolled provider.",
        "correctiveActions": [
          {
            "step": "Verify the rendering provider's NPI",
            "detail": "Confirm the individual rendering provider's NPI is correctly entered in the rendering provider loop, not just the billing/group NPI."
          },
          {
            "step": "Confirm the rendering provider is enrolled and credentialed",
            "detail": "Check that the rendering provider is credentialed with the payer and linked correctly to the billing group before resubmitting."
          }
        ],
        "relatedCarc": [
          "16"
        ],
        "sourceUrl": "https://docs.claim.md/docs/remittance-advice-remarks-codes",
        "confidence": "verify"
      }
    ],
    "unknownRarc": [],
    "correctiveActions": [
      {
        "step": "Verify the contract rate",
        "detail": "Pull the current fee schedule or contract rate sheet for this payer and CPT code and confirm the allowed amount matches what was paid."
      },
      {
        "step": "Write off per contract",
        "detail": "If the allowed amount is correct per contract, adjust off the difference. This is a standard contractual adjustment, not an error."
      },
      {
        "step": "Check for a fee schedule update lag",
        "detail": "If the payer recently updated its fee schedule, confirm the correct effective date was applied to this date of service."
      },
      {
        "step": "Verify the rendering provider's NPI",
        "detail": "Confirm the individual rendering provider's NPI is correctly entered in the rendering provider loop, not just the billing/group NPI."
      },
      {
        "step": "Confirm the rendering provider is enrolled and credentialed",
        "detail": "Check that the rendering provider is credentialed with the payer and linked correctly to the billing group before resubmitting."
      }
    ],
    "appeal": {
      "worthiness": "low",
      "note": "Appeal only if you can show the payer used the wrong fee schedule, wrong contract year, or the code is not actually subject to that schedule. Otherwise this is a routine contractual write off and not appealable.",
      "payer": {
        "payer": "Medicare (Original / Part B)",
        "slug": "medicare",
        "initialClaimLimitDays": 365,
        "limitText": "12 months (1 calendar year) from the date of service",
        "clockStartsFrom": "date of service",
        "appealLimitDays": 120,
        "notes": "Set by federal regulation at 42 CFR 424.44, not by contract, so this figure does not vary by Medicare Administrative Contractor. Claims denied for untimely filing carry no appeal rights for the timeliness issue itself; the 120-day figure is the standard redetermination (first-level appeal) deadline for a substantive denial, measured from the date of the initial determination.",
        "sourceUrl": "https://www.medicare.gov/providers-services/claims-appeals-complaints/claims",
        "confidence": "verified"
      },
      "deadlineDays": 120
    },
    "note": ""
  },
  "request_id": "req_2f9c41a7b0e84d15",
  "disclaimer": "Denial7 provides billing and administrative guidance based on published CMS and X12 sources. It is not medical advice, not a coverage determination, and not a guarantee of payment. NCCI and MUE edits are republished quarterly and payer policies vary by contract. Always confirm against the payer's own current policy before submitting or appealing.",
  "attribution": "Data from Denial7 (https://denial7.com): CMS NCCI/MUE edits and X12 CARC/RARC codes, cited by source and confidence. Free responses require this attribution."
}

request

curl "https://denial7.com/api/v1/ncci?column1=80053&column2=80048&dateOfService=2026-07-01"

response 200

{
  "data": {
    "column1": "80053",
    "column2": "80048",
    "dateOfService": "2026-07-01",
    "editQuarter": "2026 Q3",
    "found": true,
    "appliesOnDate": true,
    "status": "applies",
    "edit": {
      "column1": "80053",
      "column2": "80048",
      "modifierIndicator": "0",
      "effectiveDate": "2000-07-01",
      "deletionDate": null,
      "rationale": "CPT Manual or CMS manual coding instruction",
      "note": "",
      "sourceUrl": "https://www.cms.gov/medicare/coding-billing/national-correct-coding-initiative-ncci-edits/medicare-ncci-procedure-procedure-ptp-edits",
      "confidence": "verified"
    }
  },
  "request_id": "req_2f9c41a7b0e84d15",
  "disclaimer": "Denial7 provides billing and administrative guidance based on published CMS and X12 sources. It is not medical advice, not a coverage determination, and not a guarantee of payment. NCCI and MUE edits are republished quarterly and payer policies vary by contract. Always confirm against the payer's own current policy before submitting or appealing.",
  "attribution": "Data from Denial7 (https://denial7.com): CMS NCCI/MUE edits and X12 CARC/RARC codes, cited by source and confidence. Free responses require this attribution."
}

request

curl "https://denial7.com/api/v1/mue?code=36415"

response 200

{
  "data": {
    "code": "36415",
    "status": "found",
    "limit": {
      "code": "36415",
      "mueValue": 2,
      "mai": "3",
      "maiMeaning": "Date of service edit, clinical. Units above this limit are unlikely but not impossible. A higher count can be allowed on appeal when the medical record supports it.",
      "serviceType": "Practitioner",
      "note": "CMS published rationale for this limit: CMS Policy.",
      "sourceUrl": "https://www.cms.gov/medicare/coding-billing/national-correct-coding-initiative-ncci-edits/medicare-ncci-medically-unlikely-edits",
      "confidence": "verified"
    }
  },
  "request_id": "req_2f9c41a7b0e84d15",
  "disclaimer": "Denial7 provides billing and administrative guidance based on published CMS and X12 sources. It is not medical advice, not a coverage determination, and not a guarantee of payment. NCCI and MUE edits are republished quarterly and payer policies vary by contract. Always confirm against the payer's own current policy before submitting or appealing.",
  "attribution": "Data from Denial7 (https://denial7.com): CMS NCCI/MUE edits and X12 CARC/RARC codes, cited by source and confidence. Free responses require this attribution."
}

request

curl -X POST https://denial7.com/api/v1/appeal \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $DENIAL7_API_KEY" \
  -H "Idempotency-Key: appeal-demo-1" \
  -d '{"carc":"CO-45","payerSlug":"aetna","claimNumber":"CLM-10293"}'

response 200

{
  "data": {
    "subject": "Request for reconsideration - claim CLM-10293 - CO-45",
    "body": "2026-08-11\n\nAetna\nAttn: Claims Review / Appeals Department\n\nRe: Request for reconsideration\nClaim number: CLM-10293\nDate of service: [TO BE COMPLETED BY PRACTICE]\nProcedure code(s) at issue: [TO BE COMPLETED BY PRACTICE]\nProvider: [TO BE COMPLETED BY PRACTICE]\n\nTo whom it may concern,\n\nWe are writing to request reconsideration of the adjustment applied to the claim referenced above.\n\nThe remittance reports CO-45: Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement..\n\nThe payer is telling you the billed charge is higher than the amount their fee schedule or contract allows for this service. The difference between what you billed and what the payer allows becomes a contractual write off, not something you can bill the patient for when an in network contract is in place.\n\nBasis for reconsideration:\n1. Verify the contract rate. Pull the current fee schedule or contract rate sheet for this payer and CPT code and confirm the allowed amount matches what was paid.\n2. Write off per contract. If the allowed amount is correct per contract, adjust off the difference. This is a standard contractual adjustment, not an error.\n3. Check for a fee schedule update lag. If the payer recently updated its fee schedule, confirm the correct effective date was applied to this date of service.\n\nThis request is submitted within the appeal window stated in our participation agreement.\n\nWe ask that the claim be reprocessed. Supporting documentation is enclosed. Please contact the billing office at the number on file if any further information would assist the review.\n\nSincerely,\n\n[TO BE COMPLETED BY PRACTICE]\n[TO BE COMPLETED BY PRACTICE]",
    "citations": [
      {
        "source": "X12 Claim Adjustment Reason Codes",
        "url": "https://x12.org/codes/claim-adjustment-reason-codes",
        "confidence": "verified"
      },
      {
        "source": "Aetna timely filing and appeal policy",
        "url": "https://muni.health/blog/aetna-timely-filing-limits-2026",
        "confidence": "verify"
      }
    ],
    "placeholders": [
      "Provider or practice name",
      "Date of service",
      "Procedure codes at issue",
      "Signature, name and title of the person sending the letter"
    ],
    "grounded": true
  },
  "request_id": "req_2f9c41a7b0e84d15",
  "disclaimer": "Denial7 provides billing and administrative guidance based on published CMS and X12 sources. It is not medical advice, not a coverage determination, and not a guarantee of payment. NCCI and MUE edits are republished quarterly and payer policies vary by contract. Always confirm against the payer's own current policy before submitting or appealing.",
  "attribution": "Data from Denial7 (https://denial7.com): CMS NCCI/MUE edits and X12 CARC/RARC codes, cited by source and confidence. Free responses require this attribution."
}

request

curl "https://denial7.com/api/v1/timely-filing?payer=aetna&dateOfService=2026-01-15"

response 200

{
  "data": {
    "payerSlug": "aetna",
    "dateOfService": "2026-01-15",
    "checkedAt": "2026-08-11",
    "payer": {
      "payer": "Aetna",
      "slug": "aetna",
      "initialClaimLimitDays": 90,
      "limitText": "90 days from date of service for participating/in-network commercial providers; non-participating providers commonly have up to 12 months, per Aetna's published guidance",
      "clockStartsFrom": "date of service",
      "appealLimitDays": null,
      "notes": "The published default varies further by product (commercial, Medicare Advantage, Aetna Better Health Medicaid plans) and by the specific network contract. This entry reflects secondary-source reporting on Aetna's provider guidance rather than a directly confirmed page from aetna.com; verify against the current provider manual for the member's specific plan before acting.",
      "sourceUrl": "https://muni.health/blog/aetna-timely-filing-limits-2026",
      "confidence": "verify"
    },
    "daysElapsed": 208,
    "daysRemaining": -118,
    "expired": true,
    "note": ""
  },
  "request_id": "req_2f9c41a7b0e84d15",
  "disclaimer": "Denial7 provides billing and administrative guidance based on published CMS and X12 sources. It is not medical advice, not a coverage determination, and not a guarantee of payment. NCCI and MUE edits are republished quarterly and payer policies vary by contract. Always confirm against the payer's own current policy before submitting or appealing.",
  "attribution": "Data from Denial7 (https://denial7.com): CMS NCCI/MUE edits and X12 CARC/RARC codes, cited by source and confidence. Free responses require this attribution."
}

request

curl https://denial7.com/api/v1/pricing

response 200

{
  "data": {
    "currency": "usd",
    "unit": "Metered by billable call once you send a live key on a paid plan. Anonymous and test-key calls never bill; they are rate-limited instead.",
    "determinism": "Every response is a projection of a cited CMS or X12 dataset plus deterministic arithmetic. There is no model in the request path, so the same query always returns the same answer. Every edit and code carries a `confidence` of \"verified\" or \"verify\" (render \"verify\" as Unverified, never as fact) and, where versioned, the CMS edit `quarter` it belongs to. Where the loaded dataset holds no edit for a code or pair, the response says `no_data` rather than reporting a pass: absence of data is never treated as a clean result. Procedure codes are referenced numerically only; CPT long descriptors are AMA-copyrighted and are never reproduced by this API.",
    "anonymous": {
      "price_usd": 0,
      "rate_limit_per_minute": 4,
      "rate_limit_per_day": 20,
      "api_access": false,
      "appeal_letters": false,
      "note": "No key needed. Every lookup endpoint (scrub, denial, ncci, mue, timely-filing) works at this throttled rate. POST /api/v1/appeal always requires a Pro or Scale plan, regardless of throttle."
    },
    "test_key": {
      "rate_limit_per_minute": 10,
      "rate_limit_per_day": 200,
      "bills": false,
      "appeal_letters": false,
      "note": "A ld_test_ key (see /api/v1 auth) never bills and never unlocks appeal letters; it only raises the anonymous throttle."
    },
    "plans": [
      {
        "id": "free",
        "name": "Free",
        "price_usd_per_month": 0,
        "cadence": "free forever",
        "tagline": "Scrub a claim, look up any denial code. No card, no signup.",
        "included_api_calls_per_month": 0,
        "rate_limit_per_minute": 0,
        "batch_claims_per_run": 0,
        "saved_claims": 0,
        "seats": 1,
        "api_access": false,
        "claim_history": false,
        "batch_scrub": false,
        "appeal_letters": false,
        "denial_analytics": false,
        "priority_support": false,
        "features": [
          "Single-claim scrubber, runs in your browser so claim data is never transmitted",
          "Every CARC and RARC denial page, with cited corrective actions",
          "NCCI PTP and MUE verdicts with the CMS citation and edit quarter",
          "Test API key for developers (throttled, never bills)",
          "Public API and MCP at the anonymous rate"
        ]
      },
      {
        "id": "pro",
        "name": "Pro",
        "price_usd_per_month": 49,
        "cadence": "per month",
        "tagline": "For the biller or practice working denials every week.",
        "included_api_calls_per_month": 1000,
        "rate_limit_per_minute": 60,
        "batch_claims_per_run": 250,
        "saved_claims": "unlimited",
        "seats": 1,
        "api_access": true,
        "claim_history": true,
        "batch_scrub": true,
        "appeal_letters": true,
        "denial_analytics": true,
        "priority_support": false,
        "features": [
          "Batch scrubbing, up to 250 claims per run",
          "Saved claim history with the verdict and the CMS quarter it was checked against",
          "Appeal letter generation and download, with the citations that justify it",
          "Denial analytics by payer across your saved claims",
          "Claim scrubbing API, 1,000 calls/mo included",
          "Hosted MCP server at your plan's burst rate instead of the anonymous rate",
          "Inspectable request log"
        ]
      },
      {
        "id": "scale",
        "name": "Scale",
        "price_usd_per_month": 149,
        "cadence": "per month",
        "tagline": "For billing companies and products built on the API.",
        "included_api_calls_per_month": 10000,
        "rate_limit_per_minute": 300,
        "batch_claims_per_run": 2000,
        "saved_claims": "unlimited",
        "seats": 1,
        "api_access": true,
        "claim_history": true,
        "batch_scrub": true,
        "appeal_letters": true,
        "denial_analytics": true,
        "priority_support": true,
        "features": [
          "Everything in Pro",
          "10,000 API calls/mo",
          "300 requests/minute burst",
          "Batch scrubbing up to 2,000 claims per run",
          "Priority support"
        ]
      }
    ],
    "checkout": {
      "note": "There is no machine-callable checkout API: a signed-in human starts Stripe Checkout from the billing page. An agent choosing a plan on a user's behalf should direct them to upgrade_url.",
      "upgrade_url": "https://denial7.com/pricing"
    }
  },
  "request_id": "req_2f9c41a7b0e84d15",
  "disclaimer": "Denial7 provides billing and administrative guidance based on published CMS and X12 sources. It is not medical advice, not a coverage determination, and not a guarantee of payment. NCCI and MUE edits are republished quarterly and payer policies vary by contract. Always confirm against the payer's own current policy before submitting or appealing.",
  "attribution": "Data from Denial7 (https://denial7.com): CMS NCCI/MUE edits and X12 CARC/RARC codes, cited by source and confidence. Free responses require this attribution."
}