SlowPokeAPI

Currency exchange rate API built in Rust.

Lines of Code: ~15,000 | Binary Size: ~8MB

Features

• Multi-Source Data: Aggregates rates from Frankfurter, fawazahmed0, CoinGecko, and CoinCap
• Cryptocurrency Support: BTC, ETH, and 15 other cryptocurrencies
• Precious Metals: XAU (gold), XAG (silver), XPT (platinum), XPD (palladium)
• Caching: Tiered cache (in-memory + SQLite) with configurable TTL
• Observability: Prometheus metrics, health checks, distributed tracing
• Rate Limiting: Token bucket rate limiting per client
• Authentication: Optional API key authentication

Quick Start

Using Docker

docker run -p 8080:8080 ghcr.io/e6qu/slowpokeapi:latest

Using Docker Compose

docker-compose up -d

Building from Source

git clone https://github.com/e6qu/slowpokeapi.git
cd slowpokeapi
cargo build --release
./target/release/slowpokeapi

API Overview

Endpoint	Description
GET /v1/currencies	List all supported currencies
GET /v1/latest/{base_code}	Latest rates for base currency
GET /v1/pair/{base}/{target}	Convert between two currencies
GET /v1/history/{base}/{y}/{m}/{d}	Historical rates for date
GET /v1/enriched/{base}/{target}	Rate with target metadata
GET /health	Health check
GET /metrics	Prometheus metrics

Example Request

curl http://localhost:8080/v1/latest/USD

Example Response

{
  "base_code": "USD",
  "conversion_rates": {
    "EUR": 0.85,
    "GBP": 0.73,
    "JPY": 110.0
  },
  "documentation": "https://github.com/e6qu/slowpokeapi",
  "result": "success",
  "time_last_update_unix": 1640995200,
  "time_next_update_unix": 1641081600,
  "data_source": {
    "source": "frankfurter",
    "last_retrieved": "2024-01-01T00:00:00Z",
    "last_cached": null,
    "upstream_request": {
      "endpoint": "https://api.frankfurter.app/latest?from=USD"
    }
  }
}

Configuration

Configuration is via environment variables with the prefix SLOWPOKEAPI__:

Variable	Default	Description
SLOWPOKEAPI__SERVER__PORT	8080	HTTP port
SLOWPOKEAPI__DATABASE__URL	sqlite::memory:	SQLite database path
SLOWPOKEAPI__CACHE__TTL_SECONDS	3600	Cache TTL in seconds
SLOWPOKEAPI__RATE_LIMIT__ENABLED	true	Enable rate limiting
SLOWPOKEAPI__AUTH__ENABLED	false	Enable API key authentication

See docs/DEPLOYMENT.md for complete configuration reference.

Deployment Options

• Binary: Single static binary
• Docker: Multi-platform images
• Docker Compose: Stack with Prometheus and Grafana
• Kubernetes: Helm chart
• AWS ECS: Terraform modules

See docs/DEPLOYMENT.md for detailed deployment guides.

Development

Prerequisites

• Rust 1.75+
• SQLite 3
• Docker (optional)

Running Tests

cargo test --all-features

Running Lints

cargo fmt --check
cargo clippy --all-targets --all-features -- -D warnings

Architecture

                    ┌─────────────┐
                    │   Client    │
                    └──────┬──────┘
                           │
                           ▼
                    ┌─────────────┐
                    │  Axum HTTP  │
                    └──────┬──────┘
                           │
                           ▼
                    ┌─────────────┐
                    │   Handler   │
                    └──────┬──────┘
                           │
        ┌──────────────────┼──────────────────┐
        │                  │                  │
        ▼                  ▼                  ▼
 ┌─────────────┐   ┌─────────────┐   ┌─────────────┐
 │  Tiered     │   │ Rate Limiter│   │ Auth/Key    │
 │ Cache       │   │             │   │ Storage     │
 │(Mem+SQLite) │   │             │   │             │
 └──────┬──────┘   └─────────────┘   └─────────────┘
        │
        ▼
 ┌─────────────┐
 │  Upstream   │
 │  Manager    │
 └──────┬──────┘
        │
   ┌────┴────┬────────┐
   │         │        │
   ▼         ▼        ▼
┌──────┐ ┌──────┐ ┌──────┐
│Frank-│ │Coin- │ │Coin- │
│furter│ │Gecko │ │Cap   │
└──────┘ └──────┘ └──────┘

Documentation

• Deployment Guide - Installation and deployment options
• API Reference - Complete API documentation
• CHANGELOG.md - Version history

Monitoring

• Metrics: Prometheus metrics at /metrics
• Health: Health check at /health
• Grafana: Dashboard template in deploy/grafana/
• Alerts: Prometheus alert rules in deploy/prometheus/

License

Dual-licensed under AGPL-3.0 or MIT at your option. See LICENSE for details.

About

This project is a reimplementation developed independently based on publicly available information. It is not affiliated with or endorsed by RapidAPI.