diff --git a/.env.example b/.env.example
index ef5494b..2c3fc03 100644
--- a/.env.example
+++ b/.env.example
@@ -16,18 +16,17 @@ MAX_BLOCKS_PER_BATCH=1000
 PRICE_CACHE_TTL_MS=120000
 PG_MAX_CLIENTS=10
 
-# CoinGecko Configuration (optional)
+# CoinGecko Configuration.
 #
-# Three deployment modes, in priority order:
-#  1. Caching pricing proxy: set COINGECKO_BASE_URL to the proxy origin, leave
-#     COINGECKO_API_KEY empty. The proxy injects the upstream key itself.
-#       COINGECKO_BASE_URL=http://pricing-proxy:8080/coingecko
-#  2. Direct Pro tier: set COINGECKO_API_KEY to a Pro key, leave
-#     COINGECKO_BASE_URL empty. Calls go to pro-api.coingecko.com with
-#     `x-cg-pro-api-key`.
-#       COINGECKO_API_KEY=CG-xxxxxxxxxxxxxxxxxxxxxxxx
-#  3. Anonymous: leave both empty — calls hit api.coingecko.com unauthenticated.
-# COINGECKO_BASE_URL=
+# COINGECKO_BASE_URL: required. The origin the service calls. Recommended is
+# the in-cluster pricing-proxy (https://github.com/DFXswiss/pricing-proxy),
+# which holds the upstream Pro key and serves a 60 s shared cache. Anything
+# CoinGecko-compatible works (pro-api.coingecko.com, api.coingecko.com, …).
+COINGECKO_BASE_URL=http://pricing-proxy:8080/coingecko
+#
+# COINGECKO_API_KEY: optional. If set, attached as `x-cg-pro-api-key` to every
+# request. Leave unset when talking to the pricing-proxy (proxy injects its
+# own key) or to the public host anonymously.
 # COINGECKO_API_KEY=
 
 # Telegram Bot Configuration (optional)
diff --git a/README.md b/README.md
index 548b83d..7c2f0d9 100644
--- a/README.md
+++ b/README.md
@@ -35,6 +35,7 @@ cp .env.example .env
 # - DATABASE_URL: PostgreSQL connection string
 # - RPC_URL: Ethereum mainnet RPC endpoint
 # - BLOCKCHAIN_ID: Must be 1 (Ethereum mainnet)
+# - COINGECKO_BASE_URL: required, see "CoinGecko" section below
 
 # Generate Prisma client
 npm run prisma:generate
@@ -67,6 +68,38 @@ docker rm -f deuro-test
 
 Swagger documentation available at: `http://localhost:3001/swagger`
 
+## CoinGecko
+
+The monitoring service needs a CoinGecko-compatible endpoint for USD/EUR
+and USD/CHF FX rates (drives EUR-denominated price conversions and the
+staleness watchdog) and the daily Pro quota probe. Configuration is two
+env vars:
+
+| Var | Required | Purpose |
+|---|---|---|
+| `COINGECKO_BASE_URL` | yes | Origin the service calls. |
+| `COINGECKO_API_KEY` | no | Attached as the `x-cg-pro-api-key` header on every request when set. |
+
+The recommended deployment is the
+[**pricing-proxy**](https://github.com/DFXswiss/pricing-proxy) — a small
+caching reverse-proxy in front of CoinGecko Pro. It holds the upstream key,
+serves a 60 s shared cache, validates upstream error envelopes, and
+coalesces concurrent identical requests. When you use the proxy:
+
+```env
+COINGECKO_BASE_URL=http://pricing-proxy:8080/coingecko
+# COINGECKO_API_KEY left unset — the proxy injects its own key
+```
+
+Without the proxy you can talk to CoinGecko directly:
+
+```env
+COINGECKO_BASE_URL=https://pro-api.coingecko.com
+COINGECKO_API_KEY=CG-xxxxxxxxxxxxxxxxxxxxxxxx
+```
+
+The service refuses to start without `COINGECKO_BASE_URL`.
+
 ## Deployment
 
 - **Development**: Push to `develop` branch → auto-deploys to `dev.monitoring.deuro.com`
diff --git a/src/config/monitoring.config.ts b/src/config/monitoring.config.ts
index 1ed2df8..a0018d3 100644
--- a/src/config/monitoring.config.ts
+++ b/src/config/monitoring.config.ts
@@ -69,11 +69,11 @@ export class MonitoringConfig {
 
 	@IsOptional()
 	@IsString()
-	coingeckoApiKey?: string;
+	coingeckoBaseUrl?: string;
 
 	@IsOptional()
 	@IsString()
-	coingeckoBaseUrl?: string;
+	coingeckoApiKey?: string;
 
 	@IsOptional()
 	@IsString()
@@ -103,8 +103,8 @@ export default registerAs('monitoring', () => {
 	config.telegramGroupsJson = process.env.TELEGRAM_GROUPS_JSON;
 	config.telegramAlertsEnabled = (process.env.TELEGRAM_ALERTS_ENABLED || 'false').toLowerCase() === 'true';
 	config.alertTimeframeHours = parseInt(process.env.ALERT_TIMEFRAME_HOURS || '12');
-	config.coingeckoApiKey = process.env.COINGECKO_API_KEY || '';
 	config.coingeckoBaseUrl = process.env.COINGECKO_BASE_URL || '';
+	config.coingeckoApiKey = process.env.COINGECKO_API_KEY || '';
 	config.environment = process.env.ENVIRONMENT?.toLowerCase();
 	config.chain = process.env.CHAIN;
 
diff --git a/src/monitoringV2/price.service.ts b/src/monitoringV2/price.service.ts
index e26841f..b36096a 100644
--- a/src/monitoringV2/price.service.ts
+++ b/src/monitoringV2/price.service.ts
@@ -71,6 +71,9 @@ export class PriceService {
 		private readonly telegramService: TelegramService
 	) {
 		this.CACHE_TTL_MS = this.appConfigService.priceCacheTtlMs;
+		if (!this.appConfigService.coingeckoBaseUrl) {
+			throw new Error('COINGECKO_BASE_URL is not set');
+		}
 	}
 
 	async getTokenPricesInEur(addresses: string[]): Promise<{ [key: string]: string }> {
@@ -202,27 +205,30 @@ export class PriceService {
 	}
 
 	/**
-	 * Resolve which CoinGecko endpoint and authentication header to use.
+	 * Resolve the CoinGecko endpoint.
+	 *
+	 * `COINGECKO_BASE_URL` is required and points at the origin the service
+	 * talks to — typically the in-cluster pricing-proxy
+	 * (https://github.com/DFXswiss/pricing-proxy), but any CoinGecko-compatible
+	 * origin works (e.g. `https://pro-api.coingecko.com` or
+	 * `https://api.coingecko.com`).
 	 *
-	 * Three modes, in priority order:
-	 *  1. `COINGECKO_BASE_URL` set → trust the caller (typically a pricing proxy
-	 *     that injects the upstream key itself); send no auth header.
-	 *  2. `COINGECKO_API_KEY` set → Pro tier: pro-api.coingecko.com with
-	 *     `x-cg-pro-api-key`.
-	 *  3. Otherwise → unauthenticated public endpoint.
+	 * `COINGECKO_API_KEY` is optional and is attached as the
+	 * `x-cg-pro-api-key` header on every request when set. Leave it unset when
+	 * talking to the pricing-proxy (the proxy injects its own key) or when
+	 * hitting the public host anonymously.
 	 */
 	private resolveCoingeckoEndpoint(): CoingeckoEndpoint {
-		const headers: Record<string, string> = { accept: 'application/json' };
-		const explicitBase = this.appConfigService.coingeckoBaseUrl;
-		if (explicitBase) {
-			return { baseUrl: explicitBase, headers };
+		const baseUrl = this.appConfigService.coingeckoBaseUrl;
+		if (!baseUrl) {
+			throw new Error('COINGECKO_BASE_URL is not set');
 		}
+		const headers: Record<string, string> = { accept: 'application/json' };
 		const apiKey = this.appConfigService.coingeckoApiKey;
 		if (apiKey) {
 			headers['x-cg-pro-api-key'] = apiKey;
-			return { baseUrl: 'https://pro-api.coingecko.com', headers };
 		}
-		return { baseUrl: 'https://api.coingecko.com', headers };
+		return { baseUrl, headers };
 	}
 
 	private async fetchFxRates(
@@ -297,20 +303,12 @@ export class PriceService {
 	}
 
 	/**
-	 * Daily probe of /api/v3/key. Emits a critical alert when the monthly
-	 * remaining call credit drops below QUOTA_REMAINING_ALERT_THRESHOLD.
-	 *
-	 * Routes through the same endpoint resolution as price calls so a proxy
-	 * deployment (key held only by the proxy) is still covered. Skipped only
-	 * when the service runs fully anonymous (no proxy and no key) — in that
-	 * case there is no Pro account to monitor.
+	 * Daily probe of /api/v3/key through the pricing proxy. Emits a critical
+	 * alert when the monthly remaining call credit drops below
+	 * QUOTA_REMAINING_ALERT_THRESHOLD.
 	 */
 	@Cron(CronExpression.EVERY_DAY_AT_NOON)
 	async checkCoingeckoQuota(): Promise<void> {
-		const explicitBase = this.appConfigService.coingeckoBaseUrl;
-		const apiKey = this.appConfigService.coingeckoApiKey;
-		if (!explicitBase && !apiKey) return;
-
 		try {
 			const { baseUrl, headers } = this.resolveCoingeckoEndpoint();
 			const response = await axios.get<CoingeckoKeyInfo>(`${baseUrl}/api/v3/key`, {