🛠 Client HTTP : consommer une API depuis la Pico W

Objectives

In the other direction: the Pico W becomes an HTTP client. This is the foundational step for any sensor dashboard, connected alarm clock, or weather display. MicroPython includes the requests library, which hides sockets behind requests.get / requests.post. You will also see how the same operation is written on the two other recommended stacks for the Pico W: CircuitPython (module wifi + socketpool, official port raspberry_pi_pico_w) and Arduino via the community core Philhower arduino-pico (recommended by Adafruit, WiFi.h mapped to the cyw43 driver).

Hardware

• 1 × Raspberry Pi Pico W + MicroPython _picow firmware
• Internet access via the access point (2.4 GHz)
• Serial console at 115200 baud
• A simple HTTP URL for testing (a public JSON API, or your server from the previous tutorial)

Complete code

# http_client.py — GET + POST JSON depuis la Pico W (MicroPython)
import machine, network, time

wlan = network.WLAN; wlan.active(True)
if not wlan.isconnected:
    wlan.connect('my_ssid', 'my_password')
    while not wlan.isconnected:
        machine.idle

import requests                      # bundlé dans MicroPython
r = requests.get('http://example.com')
print(r.status_code, r.text[:60])    # 200 + début du corps

# Version CircuitPython (board raspberry_pi_pico_w) — identifiants dans
# CIRCUITPY_WIFI_SSID / CIRCUITPY_WIFI_PASSWORD du fichier settings.toml :
#   import wifi, socketpool, requests
#   pool = socketpool.SocketPool(wifi.radio)
#   r = requests.get('http://example.com', pool=pool)
# > 
# wifi.radio.connect non revérifiés sur la doc CircuitPython (404 au fetch).

Expected verification

200 followed by the first characters of the page is displayed on the console. With a JSON API, replace the truncation with r.json to obtain a usable Python dictionary. With HTTPS (https://), MicroPython verifies the certificate: an accurate clock and valid CAs are required (see the NTP tutorial).

Common errors

• HTTPS without an updated time: X.509 certificate validation fails on a clock stuck in 2000 — synchronize the time (NTP) or test with HTTP first.
• Forgetting pool=pool in CircuitPython: requests falls back to the default network interface and the call fails; on the Pico W you must pass SocketPool(wifi.radio).
• Chunked/gzipped response poorly handled by r.text: some APIs send gzip that MicroPython does not decompress — choose a plain-text API or decode the headers yourself.
• Default timeout too short on a congested Wi-Fi network: pass timeout= to requests.get.
• Believing CircuitPython supports BLE: on the Pico W, BLE is not supported by CircuitPython (hardware capability only) — for Bluetooth, switch to MicroPython (bluetooth/aioble) or the C SDK with BTstack.
• Spamming APIs without backoff: the radio consumes a lot of power; group your requests and sleep between them (time.sleep).