Pythonで使える無料API 10選 ── 商用可・実務コード・安全設計付きガイド

pip install requests

import requests

url = "https://api.example.com/data"

try:
    response = requests.get(url, timeout=5)
    response.raise_for_status()
    data = response.json()
    print(data)
except requests.exceptions.Timeout:
    print("タイムアウト: サーバーが応答しません")
except requests.exceptions.HTTPError as e:
    print(f"HTTPエラー: {e.response.status_code}")
except requests.exceptions.RequestException as e:
    print(f"リクエストエラー: {e}")
except ValueError:
    print("JSONデコードエラー: レスポンスがJSON形式ではありません")

import requests

url = "https://api.open-meteo.com/v1/forecast"
params = {
    "latitude": 35.6762,
    "longitude": 139.6503,
    "current_weather": True
}

response = requests.get(url, params=params, timeout=5)
data = response.json()

weather = data["current_weather"]
print(f"気温: {weather['temperature']}°C")
print(f"風速: {weather['windspeed']} km/h")

import requests

url = "https://open.er-api.com/v6/latest/USD"
response = requests.get(url, timeout=5)
data = response.json()

jpy_rate = data["rates"]["JPY"]
print(f"1 USD = {jpy_rate} JPY")

# 通貨変換の例
usd_amount = 100
jpy_amount = usd_amount * jpy_rate
print(f"{usd_amount} USD = {jpy_amount:.0f} JPY")

import requests

url = "https://api.coingecko.com/api/v3/simple/price"
params = {
    "ids": "bitcoin,ethereum",
    "vs_currencies": "jpy,usd",
    "include_24hr_change": "true"
}

response = requests.get(url, params=params, timeout=5)
data = response.json()

btc = data["bitcoin"]
print(f"BTC: ¥{btc['jpy']:,.0f} (24h: {btc['jpy_24h_change']:.1f}%)")

import requests

# 投稿一覧を取得
url = "https://jsonplaceholder.typicode.com/posts"
params = {"_limit": 3}
response = requests.get(url, params=params, timeout=5)
posts = response.json()

for post in posts:
    print(f"[{post['id']}] {post['title']}")

# POST リクエストの練習
new_post = {"title": "Test", "body": "Hello", "userId": 1}
res = requests.post(url, json=new_post, timeout=5)
print(f"作成: status={res.status_code}")

import requests

url = "https://restcountries.com/v3.1/name/japan"
response = requests.get(url, timeout=5)
data = response.json()[0]

print(f"国名: {data['name']['common']}")
print(f"首都: {data['capital'][0]}")
print(f"人口: {data['population']:,}")
print(f"地域: {data['region']}")
print(f"国旗: {data['flag']}")

import requests

url = "https://api.thecatapi.com/v1/images/search"
params = {"limit": 3}
response = requests.get(url, params=params, timeout=5)
images = response.json()

for img in images:
    print(f"URL: {img['url']} (size: {img['width']}x{img['height']})")

import requests

# 自分のIPの情報を取得
url = "http://ip-api.com/json/"
response = requests.get(url, timeout=5)
data = response.json()

print(f"国: {data['country']}")
print(f"地域: {data['regionName']}")
print(f"都市: {data['city']}")
print(f"ISP: {data['isp']}")
print(f"タイムゾーン: {data['timezone']}")

import requests

url = "https://api.adviceslip.com/advice"
response = requests.get(url, timeout=5)
data = response.json()

advice = data["slip"]["advice"]
print(f"Today's advice: {advice}")

import requests

url = "https://pokeapi.co/api/v2/pokemon/pikachu"
response = requests.get(url, timeout=5)
data = response.json()

print(f"名前: {data['name']}")
print(f"タイプ: {data['types'][0]['type']['name']}")
print(f"HP: {data['stats'][0]['base_stat']}")
print(f"画像: {data['sprites']['front_default']}")

import requests

number = 42
url = f"http://numbersapi.com/{number}?json"
response = requests.get(url, timeout=5)
data = response.json()

print(f"{number}: {data['text']}")
# 例: 42: 42 is the answer to the Ultimate Question ...

import requests
import time
import json
import os

CACHE_FILE = "cache.json"
CACHE_TTL = 300  # 5分

def get_with_cache(url):
    if os.path.exists(CACHE_FILE):
        with open(CACHE_FILE) as f:
            cache = json.load(f)
        if url in cache and time.time() - cache[url]["time"] < CACHE_TTL:
            return cache[url]["data"]

    response = requests.get(url, timeout=5)
    data = response.json()

    cache = {}
    if os.path.exists(CACHE_FILE):
        with open(CACHE_FILE) as f:
            cache = json.load(f)
    cache[url] = {"data": data, "time": time.time()}
    with open(CACHE_FILE, "w") as f:
        json.dump(cache, f)

    return data

import requests
import time

def safe_api_call(url, max_retries=3, delay=1):
    for attempt in range(max_retries):
        try:
            response = requests.get(url, timeout=5)
            if response.status_code == 429:  # Rate Limit
                wait = int(response.headers.get("Retry-After", delay * 2))
                time.sleep(wait)
                continue
            response.raise_for_status()
            return response.json()
        except requests.exceptions.RequestException:
            if attempt < max_retries - 1:
                time.sleep(delay * (attempt + 1))
                continue
            return None  # fallback
    return None

class WeatherProvider:
    def get_temperature(self, lat, lon):
        raise NotImplementedError

class OpenMeteoProvider(WeatherProvider):
    def get_temperature(self, lat, lon):
        url = f"https://api.open-meteo.com/v1/forecast?latitude={lat}&longitude={lon}&current_weather=true"
        data = requests.get(url, timeout=5).json()
        return data["current_weather"]["temperature"]

class PaidWeatherProvider(WeatherProvider):
    def get_temperature(self, lat, lon):
        # 有料APIへの切り替えがクラスを変えるだけで完了
        pass

# 利用側
weather = OpenMeteoProvider()
temp = weather.get_temperature(35.67, 139.65)
print(f"気温: {temp}°C")