It's pretty straightforward, just replace <username> with the person's username, and the response will give your their uuid.

Here is an example using requests:

import requests
username = 'KrisJelbring'
url = f'https://api.mojang.com/users/profiles/minecraft/{username}?'
response = requests.get(url)
uuid = response.json()['id']

print(uuid) #7125ba8b1c864508b92bb5c042ccfe2b

You can find all the documentation here If you read the first few lines you will notice that there is a rate limit of 600 requests per 10 minutes. After that rate limit is reached you will raise a KeyError. To fix this we will use a try exception.

Don't forget to install the requests library.

pip3 install requests

Getting the user's uuid

import requests

user = "Notch"

try:
  resp = requests.get(f"https://api.mojang.com/users/profiles/minecraft/{user}")
  uuid = resp.json()["id"]

  print(uuid)

except KeyError:
  resp = requests.get(f"https://api.mojang.com/users/profiles/minecraft/{user}")
  error = resp.json()["error"]

  print(error) 

Timestamps

If you want to check when a user's username at a certain time period, use a UNIX time.

import requests

user = "Notch"
ts = 1420088400  # Must be a UNIX value.

try:
  resp = requests.get(f"https://api.mojang.com/users/profiles/minecraft/{user}?at={ts}")
  uuid = resp.json()["id"]

  print(uuid)

except KeyError:
  resp = requests.get(f"https://api.mojang.com/users/profiles/minecraft/{user}?at={ts}")
  error = resp.json()["error"]

  print(error) 

The documentation is relatively straightforward.

You want to send a GET request with their username:

import requests

username = "Bob"

resp = requests.get(f"https://api.mojang.com/users/profiles/minecraft/{username}")
uuid = resp.json()["id"]

print(f"Bob's current UUID is {uuid}")

Optionally, you can include a UNIX timestamp to get the username's UUID at a specific point in time:

username = "Alice"
# UNIX timestamp that equates to 01/01/2018
timestamp = 1514764800

resp = requests.get(f"https://api.mojang.com/users/profiles/minecraft/{username}?at={timestamp}")

uuid = resp.json()["id"]

print(f"Alice's UUID on 01/01/2018 was {uuid}")

Other Solution (third party library)

Alternatively, you can use my newly released Mojang package, if you don't want to deal with the HTTP requests, JSON, and other web junk in your code.

Install it with pip by running the following console command:

python -m pip install mojang

Usage:

from mojang import MojangAPI

uuid = MojangAPI.get_uuid("Alice")
print(f"Alice's UUID is {uuid}")

# or with a timestamp
uuid = MojangAPI.get_uuid("Alice", timestamp=1514764800)
print(f"Alice's UUID on 01/01/2018 was {uuid}")