diff --git a/amanuensis/backend/lexicon.py b/amanuensis/backend/lexicon.py
index 187d50f..b8391ba 100644
--- a/amanuensis/backend/lexicon.py
+++ b/amanuensis/backend/lexicon.py
@@ -48,4 +48,4 @@ def create(
     )
     db.session.add(new_lexicon)
     db.session.commit()
-    return new_lexicon
+    return new_lexicon
\ No newline at end of file
diff --git a/amanuensis/backend/post.py b/amanuensis/backend/post.py
new file mode 100644
index 0000000..9ce635f
--- /dev/null
+++ b/amanuensis/backend/post.py
@@ -0,0 +1,42 @@
+"""
+Post query interface
+"""
+
+import re
+
+from sqlalchemy import select, func
+
+from amanuensis.db import DbContext, Post
+from amanuensis.errors import ArgumentError
+
+def create(
+    db: DbContext,
+    lexicon_id: int,
+    user_id: int,
+    body: str) -> Post:
+    """
+    Create a new post
+    """
+
+    # Verify lexicon id
+    if not isinstance(lexicon_id, int):
+        raise ArgumentError('Lexicon id must be an integer.')
+
+    # Verify user_id
+    if not (isinstance(user_id, int) or user_id is None):
+        raise ArgumentError('User id must be an integer.')
+
+    # Verify body
+    if not isinstance(body, str):
+        raise ArgumentError('Post body must be a string.')
+    if not body.strip():
+        raise ArgumentError('Post body cannot be empty.')
+
+    new_post = Post(
+        lexicon_id=lexicon_id,
+        user_id=user_id,
+        body=body
+    )
+    db.session.add(new_post)
+    db.session.commit()
+    return new_post
diff --git a/tests/test_post.py b/tests/test_post.py
new file mode 100644
index 0000000..934ddcb
--- /dev/null
+++ b/tests/test_post.py
@@ -0,0 +1,61 @@
+import pytest
+
+from amanuensis.db import *
+import amanuensis.backend.lexicon as lexiq
+import amanuensis.backend.user as userq
+import amanuensis.backend.post as postq
+import amanuensis.backend.membership as memq
+
+from amanuensis.errors import ArgumentError
+
+from .test_db import db
+
+def test_create_post(db):
+    """Test new post creation"""
+
+    # Make user and lexicon
+    new_user = userq.create(db, 'username', 'password', 'user', 'a@b.c', False)
+    assert new_user.id, 'Failed to create user'
+    new_lexicon = lexiq.create(db, 'Test', None, 'prompt')
+    assert new_lexicon.id, 'Failed to create lexicon'
+
+    # Add the user to the lexicon as an editor
+    mem = memq.create(db, new_user.id, new_lexicon.id, True)
+    assert mem, 'Failed to create membership'
+
+    # argument dictionary for post object
+    kwargs = {
+        'lexicon_id': new_lexicon.id,
+        'user_id': new_user.id,
+        'body': 'body'
+    }
+
+    # ids are integers
+    with pytest.raises(ArgumentError):
+        postq.create(db, **{**kwargs, 'user_id': 'zero'})
+    with pytest.raises(ArgumentError):
+        postq.create(db, **{**kwargs, 'lexicon_id': 'zero'})
+
+    # empty arguments don't work
+    with pytest.raises(ArgumentError):
+        postq.create(db, **{**kwargs, 'lexicon_id': ''})
+    with pytest.raises(ArgumentError):
+        postq.create(db, **{**kwargs, 'user_id': ''})
+    with pytest.raises(ArgumentError):
+        postq.create(db, **{**kwargs, 'body': ''})
+
+    # post with only whitespace doesn't work
+    with pytest.raises(ArgumentError):
+        postq.create(db, **{**kwargs, 'body': '    '})
+
+    # post creation works and populates fields
+    new_post = postq.create(db, **kwargs)
+    assert new_post
+    assert new_post.lexicon_id is not None
+    assert new_post.user_id is not None
+    assert new_post.body is not None
+
+    # post creation works when user is None
+    new_post = postq.create(db, **{**kwargs, 'user_id': None})
+    assert new_post
+    assert new_post.user_id is None