Denial Decoder - CARC & RARC Code Lookup

About

Denial Decoder gives healthcare billers, coders, and revenue cycle professionals instant access to every CARC (Claim Adjustment Reason Code) and RARC (Remittance Advice Remark Code) — with plain-English explanations that actually make sense.

Why Denial Decoder?

Stop wasting time Googling cryptic denial codes. Type a code like "CO-16" or "N517" and get:
- The official X12 description
- A plain-English explanation of what the denial really means
- Common root causes
- Step-by-step resolution actions with routing guidance (who to call, what to fix)
- Related RARC/CARC cross-references
- CAQH CORE business scenario context
- Group code classification (CO, PR, OA, PI, CR)
- Soft vs. hard denial classification
- Appeal letter templates with required attachments and filing deadlines

Key Features:
- Search by code number, keyword, or description
- Cross-navigate between related CARC and RARC codes with one click
- Top Denials reference — the most common denial codes at a glance
- Appeal guidance with copy-to-clipboard letter templates
- Recent lookup history for quick re-access
- Dark mode support for late-night billing sessions
- Side panel mode for persistent reference alongside payer portals
- Completely free — no account required, no paywalls

Privacy First:
- 100% offline — all data is bundled locally, zero network requests
- No data collection, no analytics, no tracking
- No PHI ever touches this extension
- All storage is local to your device

Data Sources:
Built on official CARC/RARC codes from X12.org, group code definitions from CMS, and CAQH CORE business scenario mappings.

Perfect for medical billers, certified coders (CPC, CCS), revenue cycle managers, practice administrators, and anyone who works with EOBs and ERA 835 remittance files.