diff --git a/fin_depo/data.py b/fin_depo/data.py
index ceef6c4..fc3ca96 100644
--- a/fin_depo/data.py
+++ b/fin_depo/data.py
@@ -11,6 +11,16 @@ from fin_defs import Asset
 @enforce_typing.enforce_types
 @dataclasses.dataclass
 class Depo(abc.ABC):
+    """A depository tracking some amount of assets.
+
+    Depo can either be DepoSingle, which is the base layer of the depository
+    structure, or nested in DepoGroup, which allows for a complex hierarcy of
+    depositories.
+
+    The depository structure exposed by each backend depends upon the logical
+    structure of the relevant service and the API of this service.
+    """
+
     name: str
     updated_time: datetime.datetime
 
@@ -29,6 +39,8 @@ class Depo(abc.ABC):
 @enforce_typing.enforce_types
 @dataclasses.dataclass
 class DepoSingle(Depo):
+    """Base level of depository."""
+
     _assets: Mapping[Asset, Decimal]
 
     def assets(self) -> Iterable[Asset]:
@@ -41,6 +53,8 @@ class DepoSingle(Depo):
 @enforce_typing.enforce_types
 @dataclasses.dataclass
 class DepoGroup(Depo):
+    """Nested depository."""
+
     nested: list[Depo]
 
     def assets(self) -> Iterable[Asset]:
diff --git a/fin_depo/defi_kraken.py b/fin_depo/defi_kraken.py
index cf7ff4d..acb77c9 100644
--- a/fin_depo/defi_kraken.py
+++ b/fin_depo/defi_kraken.py
@@ -1,3 +1,5 @@
+"""See `KrakenDepoFetcher` for documentation."""
+
 import datetime
 import logging
 from decimal import Decimal
@@ -11,6 +13,19 @@ logger = logging.getLogger(__name__)
 
 
 class KrakenDepoFetcher:
+    """Depository fetcher for [Kraken](https://www.kraken.com), the online crypto currency exchange.
+
+    Requirements for use:
+    - Account on [Kraken](https://www.kraken.com).
+    - Have performed Know Your Customer (KYC) for your account.
+    - Created API key from [Kraken Pro
+      settings](https://pro.kraken.com/app/settings/api).
+      API key must have the **Query Funds Permission**, and **should not have
+      any additional permissions**. Employ principle of least priviledge.
+
+    Depository structure: A `DepoSingle`. No nesting.
+    """
+
     def __init__(self, kraken_key: str, kraken_secret: str):
         assert kraken_key is not None, 'Missing kraken_key'
         assert kraken_secret is not None, 'Missing kraken_secret'
diff --git a/fin_depo/defi_kucoin.py b/fin_depo/defi_kucoin.py
index 0db7bd6..90c566c 100644
--- a/fin_depo/defi_kucoin.py
+++ b/fin_depo/defi_kucoin.py
@@ -1,3 +1,5 @@
+"""See `KucoinDepoFetcher` for documentation."""
+
 import datetime
 import logging
 from decimal import Decimal
@@ -11,6 +13,19 @@ logger = logging.getLogger(__name__)
 
 
 class KucoinDepoFetcher:
+    """Depository fetcher for [Kucoin](https://www.kucoin.com), the online crypto currency exchange.
+
+    Requirements for use:
+    - Account on [Kucoin](https://www.kucoin.com).
+    - Have performed Know Your Customer (KYC) for your account.
+    - Created API key from [settings menu](https://www.kucoin.com/account/api).
+      API key must have the **General Permission**, and **should not have
+      any additional permissions**. Employ principle of least priviledge.
+
+    Depository structure: An upper level depo split for each of the
+    sub-accounts (Funding, Trading, Margin, Futures...)
+    """
+
     def __init__(self, kucoin_key: str, kucoin_secret: str, kucoin_pass: str):
         assert kucoin_key is not None, 'Missing kucoin_key'
         assert kucoin_secret is not None, 'Missing kucoin_secret'
diff --git a/fin_depo/defi_partisia_blockchain.py b/fin_depo/defi_partisia_blockchain.py
index ab6f342..3883d01 100644
--- a/fin_depo/defi_partisia_blockchain.py
+++ b/fin_depo/defi_partisia_blockchain.py
@@ -1,3 +1,5 @@
+"""See `PartisiaBlockchainAccountDepoFetcher` for documentation."""
+
 import dataclasses
 import datetime
 import email.utils
@@ -137,6 +139,17 @@ BYOC_ASSETS = {
 
 
 class PartisiaBlockchainAccountDepoFetcher:
+    """Depository fetcher for individual [Partisia
+    Blockchain](https://partisiablockchain.com/) accounts, including [MPC](https://partisiablockchain.gitlab.io/documentation/pbc-fundamentals/mpc-token-model-and-account-elements.html) and
+    [Bring-Your-Own-Coin](https://partisiablockchain.gitlab.io/documentation/pbc-fundamentals/byoc/introduction-to-byoc.html).
+
+    Requirements for use:
+    - Account on Partisia Blockchain.
+
+    Depository structure: A nested depo containing both a `Native` and a `BYOC`
+    depo.
+    """
+
     def __init__(self, session, blockchain_address: str):
         assert session is not None, 'missing session'
         assert blockchain_address is not None, 'missing blockchain_address'
diff --git a/fin_depo/investbank_nordnet.py b/fin_depo/investbank_nordnet.py
index 3e5a8f0..ca9020b 100644
--- a/fin_depo/investbank_nordnet.py
+++ b/fin_depo/investbank_nordnet.py
@@ -1,4 +1,4 @@
-"""Nordnet Depository fetching for Nordnet, the scandinavian investment bank.
+"""Nordnet Depository fetching for [Nordnet](https://nordnet.dk), the online scandinavian investment bank.
 
 This fetcher uses the [Nordnet
 API](https://www.nordnet.dk/externalapi/docs/api), which requires a Nordnet
@@ -40,6 +40,21 @@ def asset_from_instrument_json(json) -> fin_defs.Asset | None:
 
 
 class NordnetDepoFetcher:
+    """Depository fetcher for [Nordnet](https://nordnet.dk), the online investment bank.
+
+    Requirements for use:
+    - Account on [Nordnet](https://nordnet.dk). This requires a MitID.
+    - Password login enabled from [settings](https://www.nordnet.dk/indstillinger/min-profil)
+
+    **Warning**: This system uses an unofficial API which uses your normal
+    Nordnet username and password for login access, with full read/write
+    access! **This is dangerous**, and any potential leak would give an
+    attacker full access to your account.
+
+    Depository structure: Each account you have access to will be given its own
+    `Depo`, with all of them nested under a "Nordnet" nested depository.
+    """
+
     def __init__(self, session, username: str, password: str):
         assert session is not None, 'missing session'
         self.session = session