diff --git a/README.md b/README.md
index aa6aa3a..ecd6bb0 100644
--- a/README.md
+++ b/README.md
@@ -3,3 +3,11 @@
 Omdat Nederlanders ook [alphaguess](https://alphaguess.com) willen spelen :)
 
 My own implementation of an alphaguess like game with custom word lists, tailored to be used with a Dutch source.
+
+
+## Environment variables
+
+```
+set -x WORD_LIST /path/to/alfagok_wordlist.txt
+set -x START_DATE 2024-11-02
+```
diff --git a/src/alfagok/main.py b/src/alfagok/main.py
index 66b8a36..621142b 100644
--- a/src/alfagok/main.py
+++ b/src/alfagok/main.py
@@ -1,23 +1,88 @@
+"""Main alfagok API application."""
+
+import logging
+from datetime import date
 from typing import Union
 
 from fastapi import FastAPI
-from pydantic_settings import BaseSettings
 from pydantic import FilePath
+from pydantic_settings import BaseSettings
 
 
 class Settings(BaseSettings):
+    """Configuration needed for alfagok to find its word list, using environment variables."""
+
+    # Game words
     word_list: FilePath
+    # All valid words
+    dictionary_list: FilePath
+    # Date of first game so we can calculate the game ID we're on
+    start_date: date
+
+    debug: bool = False
 
 
 app = FastAPI()
-settings = Settings() 
+settings = Settings()
+
+with open(settings.word_list, 'r', encoding='utf-8') as word_file:
+    # Load the game words
+    words = word_file.readlines()
+
+
+with open(settings.dictionary_list, 'r', encoding='utf-8') as word_file:
+    # Load the list of valid words
+    dictionary = word_file.readlines()
+
+
+logger = logging.getLogger('uvicorn.error')
+logger.setLevel(logging.INFO)
+if settings.debug:
+    logger.setLevel(logging.DEBUG)
+
+
+def get_game_id():
+    """Calculate the index for the game/word we are handling today."""
+    print(settings.start_date)
+    today = date.today()
+    # Calculate the amount of days since the start of the games so we know which word is used today
+    return (today - settings.start_date).days
+
+
+def is_valid_dictionary_word(word: str) -> bool:
+    """Verify if `word` is in the dictionary provided."""
+    return f'{word}\n' in dictionary
 
 
 @app.get("/")
 def read_root():
+    """Ohai."""
     return {"Hello": "World"}
 
 
-@app.get("/items/{item_id}")
-def read_item(item_id: int, q: Union[str, None] = None):
-    return {"item_id": item_id, "q": q}
+@app.get('/api/guess')
+def handle_guess(word: Union[str, None] = None):
+    """Handle incoming guess."""
+    current_game_id = get_game_id()
+    word_of_the_day = words[current_game_id].strip()
+
+    if not is_valid_dictionary_word(word):
+        return {'error': 'Word not in dictionary'}
+
+    hint = 'it'
+    if word_of_the_day < word:
+        hint = 'before'
+    if word_of_the_day > word:
+        hint = 'after'
+
+    logger.info('Guess: %s for game %d (%s), goal is %s', word, current_game_id, word_of_the_day, hint)
+
+    # before, after, it
+    return {'hint': hint}
+
+
+@app.get("/api/answer/{item_id}")
+def read_item(item_id: int, guess: Union[str, None] = None):
+    """Get the word item."""
+    word = words[item_id].strip()
+    return {"item_id": item_id, "guess": guess, 'word': word}