Normalize all reward currencies to cash-equivalent dollars

Context

Cards earn in incompatible units — cash back, transferable points, and airline miles. Ranking them head-to-head at checkout requires a single comparable unit.

Decision

Every reward currency is assigned a cents-per-unit valuation (e.g. Chase Ultimate Rewards 1.25¢, Amex Membership Rewards 1.0¢) and all earnings are expressed in cash-equivalent dollars before any comparison. The valuation table is the single source of truth for routing math.

earned value = spend × multiplier × cents-per-unit ÷ 100

Consequences

• A 4× points purchase and a 3% cash-back purchase can be ranked deterministically.
• Valuations track industry-average redemption rates and are tuned in one place (lib/rewards/normalization.ts).
• Routing quality is bounded by valuation accuracy; conservative defaults avoid over-promising on speculative redemptions.