Lux Docs

Overview

Lux FX is a cryptocurrency pricing API gateway that proxies CoinGecko with an in-memory cache. It is a single-file Go service with no external dependencies beyond the standard library. Deployed to K8s as markets in the lux-gateway namespace, serving fx.lux.network.

When to use

Querying cryptocurrency prices from Lux ecosystem services
Replacing direct CoinGecko API calls with a cached, self-hosted gateway
Deploying a lightweight pricing microservice on K8s

Quick reference

Item	Value
Repo	`github.com/luxfi/fx`
Go module	`github.com/luxfi/pricing`
Language	Go 1.26
Dependencies	None (standard library only)
Default port	8080
Cache TTL	1 hour
License	MIT
Default branch	main
Container image	`ghcr.io/luxfi/pricing:latest`

Project structure

fx/
  .github/          # CI/CD workflows
  k8s/              # Kubernetes manifests
    deployment.yaml  # 2 replicas, lux-gateway namespace
    ingress.yaml     # fx.lux.network
    secret.yaml      # CoinGecko API key
    service.yaml     # ClusterIP on port 8080
  main.go            # Entire application (single file)
  go.mod             # Module definition
  Dockerfile         # Multi-stage alpine build
  compose.yml        # Local development

API endpoints

Endpoint	Description
`GET /health`	Health check (JSON status + time)
`GET /price/\{token_id\}?currency=usd`	Single token price with market data
`GET /prices?ids=bitcoin,ethereum&currency=usd`	Multiple token prices in one request
`GET /simple/price?ids=bitcoin&vs_currencies=usd,eur`	CoinGecko-compatible simple format

One-file quickstart

git clone https://github.com/luxfi/fx.git
cd fx
export COINGECKO_API_KEY=your-api-key
go run main.go

Architecture

Client --> FX API (port 8080) --> In-Memory Cache (1h TTL) --> CoinGecko API

Key types

PriceCache -- Thread-safe in-memory cache with RWMutex, auto-fetches on miss
CachedPrice -- Price, currency, 24h change, market cap, volume, timestamp
PriceResponse -- API response with cached boolean indicator
MultiPriceResponse -- Batch response wrapping multiple PriceResponse entries

Behavior

Cache hit returns stale data if CoinGecko is unreachable (graceful degradation)
Batch fetches reduce CoinGecko API calls for multi-token requests
CORS enabled for all origins (*)
Cache-Control: public, max-age=3600 on all price responses

Environment variables

Variable	Required	Default	Description
`COINGECKO_API_KEY`	Yes	-	CoinGecko API key (demo or pro)
`PORT`	No	`8080`	Server listen port

Development

# Build
go build -o pricing .

# Run with Docker
docker compose up -d

# Deploy to K8s
kubectl apply -f k8s/

K8s deployment details

Field	Value
Namespace	`lux-gateway`
Deployment name	`markets`
Replicas	2
CPU request/limit	100m / 500m
Memory request/limit	64Mi / 256Mi
Liveness probe	`GET /health` every 10s
Readiness probe	`GET /health` every 5s
Secret	`markets-secrets` (key: `coingecko-api-key`)

lux/lux-market.md -- Market data and trading
lux/lux-node.md -- Lux node infrastructure

Lux FX - Cryptocurrency Pricing API Gateway