Forest Crypto Fear & Greed Index

Use this endpoint when you need a real-time or recent-historical sentiment signal specifically tied to the Alternative.me Crypto Fear & Greed Index for Bitcoin/crypto markets. Prefer it over raw price feeds when you want a normalized 0–100 sentiment score with classification labels and a trading signal flag. It is especially useful for agents automating daily market mood reports, enriching trade decision logic, or populating dashboards with sentiment context. It is a paid micro-transaction endpoint ($0.001 USDC) that returns structured, cached data — appropriate for high-frequency polling only if cache_age_ms is monitored.

• days parameter out of range (must be 1–30) — likely 400 Bad Request
• Unsigned or unpaid request returns HTTP 402 with x402 PAYMENT-REQUIRED challenge
• Upstream Alternative.me data unavailable — possible 503 or degraded response
• Stale cache served when upstream is slow — cache_age_ms will be elevated
• Invalid JSON body or missing Content-Type — likely 400 parse error