CryptoCross Radar — symbol hover tooltip (rank / market cap / 24h) — 2026-06-24

Small feature on the Crypto Cross Radar page (/root/crypto_bots/cryptocrossradar.py, Flask on 127.0.0.1:5054, served behind nginx at /cryptocrossradar/). Jacques asked that hovering a symbol in the table bring up a little pop-up table next to it showing the coin's current rank, market cap, and 24h % move.

The data-gap finding (why this needed an external source)

Two of the three requested fields aren't in our data at all: - The candle DB (crypto_cross.db) is OHLCV only — no market-cap, no supply. - The "rank" we do store (universe_snapshots.rank) is a 24h trading-volume rank within the tracked top-200 perps, not the market-cap rank Jacques means by "position in the top 100/200 cryptocurrencies."

So a true market-cap rank + market cap had to come from outside. Decision (agreed with Jacques): pull all three from CoinGecko's free public API (no key — fits the "no keys" rule), so rank / cap / 24h are mutually consistent and match what he'd see on CoinMarketCap-style sites.

Implementation

Backend. Added a market-context layer to /root/crypto_bots/cryptocrossradar.py: - A daemon thread fetches the top ~1,000 coins by market cap (/coins/markets, 4 pages of 250) and keeps an in-memory map base-symbol -> {rank, cap, chg}. Refreshed every 10 min. Primed once at startup so tooltips have data immediately. - Tolerant + non-regressing. The free endpoint rate-limits bursts, so each page is retried once then skipped on failure — we keep whatever pages loaded instead of discarding everything (the first naive version was all-or-nothing and showed zero data whenever a single page 429'd). A full 4-page fetch replaces the map; a partial fetch merges into the last good map, so coverage only ever grows. On any error we keep the last good map and never crash the radar. - Symbol matching is by upper-cased base; a leading thousands-prefix is stripped as a fallback (1000PEPE -> PEPE). /api/scan rows gained mc_rank/mc_cap/mc_chg24. - Reads nothing from our databases for this — zero extra load on the live DB writer.

Frontend. Each symbol cell carries the three values as data-attributes; a single delegated mouseover/mouseout handler shows a fixed-position cream pop-up (groovy theme, pointer-events:none so it never blocks the row's click-to-TradingView). Market cap formats as $T/$B/$M; 24h is green/red. Symbols got a faint dotted underline to hint they're hoverable.

Coverage (honest)

On the 1h "approaching-cross" list, ~24 of 31 rows resolve. The misses are mostly tokenized stocks on Bybit (IBM, SAMSUNG, GOOGL, NOKIA) which have no crypto market cap by definition, plus a few sub-1000 alts — all show "—", which is correct, not a bug. Verified the auto-heal in production: right after deploy a test-induced rate-limit left only 8/31; one refresh cycle later it was back to 24/31 with no intervention.

Ops

• Backed up the original to /root/crypto_bots/cryptocrossradar.py.bak_1782327315 before editing.
• Tested end-to-end on a throwaway port (5077) first, then restarted cryptocrossradar.service (with Jacques' explicit OK) — active and healthy.
• Live: the radar page, hover any symbol.

Files

/root/crypto_bots/cryptocrossradar.py (market layer + tooltip), backup /root/crypto_bots/cryptocrossradar.py.bak_1782327315. Data source: CoinGecko /coins/markets (public, no key).