diff --git a/elm.json b/elm.json
index aad9344..7c3b668 100644
--- a/elm.json
+++ b/elm.json
@@ -20,7 +20,8 @@
         "elm/time": "1.0.0 <= v < 2.0.0",
         "elm/url": "1.0.0 <= v < 2.0.0",
         "micahhahn/elm-safe-recursion": "2.0.0 <= v < 3.0.0",
-        "miniBill/elm-fast-dict": "1.0.0 <= v < 2.0.0"
+        "miniBill/elm-fast-dict": "1.0.0 <= v < 2.0.0",
+        "noordstar/elm-iddict": "1.0.1 <= v < 2.0.0"
     },
     "test-dependencies": {
         "elm-explorations/test": "2.1.2 <= v < 3.0.0"
diff --git a/src/Internal/Config/Text.elm b/src/Internal/Config/Text.elm
index 806ac16..2bfe125 100644
--- a/src/Internal/Config/Text.elm
+++ b/src/Internal/Config/Text.elm
@@ -118,7 +118,6 @@ docs :
     , event : TypeDocs
     , hashdict : TypeDocs
     , ibatch : TypeDocs
-    , iddict : TypeDocs
     , itoken : TypeDocs
     , mashdict : TypeDocs
     , room : TypeDocs
@@ -169,12 +168,6 @@ docs =
             [ "The internal batch tracks a patch of events on the Matrix timeline."
             ]
         }
-    , iddict =
-        { name = "Iddict"
-        , description =
-            [ "An iddict automatically handles creating appropriate keys by incrementally assiging a new key to new values."
-            ]
-        }
     , itoken =
         { name = "IToken"
         , description =
diff --git a/src/Internal/Tools/Iddict.elm b/src/Internal/Tools/Iddict.elm
deleted file mode 100644
index da718f2..0000000
--- a/src/Internal/Tools/Iddict.elm
+++ /dev/null
@@ -1,198 +0,0 @@
-module Internal.Tools.Iddict exposing
-    ( Iddict
-    , empty, singleton, insert, map, remove
-    , isEmpty, member, get, size
-    , keys, values
-    , coder, encode, decoder
-    )
-
-{-| The id-dict is a data type that lets us store values in a dictionary using
-unique identifiers. This can be used as a dictionary where the keys do not
-matter.
-
-The benefit of the iddict is that it generates the keys FOR you. This way, you
-do not need to generate identifiers yourself.
-
-
-## Id-dict
-
-@docs Iddict
-
-
-## Build
-
-@docs empty, singleton, insert, map, remove
-
-
-## Query
-
-@docs isEmpty, member, get, size
-
-
-## Lists
-
-@docs keys, values
-
-
-## JSON coders
-
-@docs coder, encode, decoder
-
--}
-
-import FastDict as Dict exposing (Dict)
-import Internal.Config.Text as Text
-import Internal.Tools.Json as Json
-
-
-{-| The Iddict data type.
--}
-type Iddict a
-    = Iddict
-        { cursor : Int
-        , dict : Dict Int a
-        }
-
-
-{-| Define how an Iddict can be encoded and decoded to and from a JSON value.
--}
-coder : Json.Coder a -> Json.Coder (Iddict a)
-coder x =
-    Json.object2
-        { name = Text.docs.iddict.name
-        , description = Text.docs.iddict.description
-        , init =
-            \c d ->
-                Iddict
-                    { cursor =
-                        Dict.keys d
-                            |> List.maximum
-                            |> Maybe.map ((+) 1)
-                            |> Maybe.withDefault 0
-                            |> max (Dict.size d)
-                            |> max c
-                    , dict = d
-                    }
-        }
-        (Json.field.optional.withDefault
-            { fieldName = "cursor"
-            , toField = \(Iddict i) -> i.cursor
-            , description = Text.fields.iddict.cursor
-            , coder = Json.int
-            , default = ( 0, [] )
-            , defaultToString = String.fromInt
-            }
-        )
-        (Json.field.required
-            { fieldName = "dict"
-            , toField = \(Iddict i) -> i.dict
-            , description = Text.fields.iddict.dict
-            , coder = Json.fastIntDict x
-            }
-        )
-
-
-{-| Decode an id-dict from a JSON value.
--}
-decoder : Json.Coder a -> Json.Decoder (Iddict a)
-decoder x =
-    Json.decode (coder x)
-
-
-{-| Create an empty id-dict.
--}
-empty : Iddict a
-empty =
-    Iddict
-        { cursor = 0
-        , dict = Dict.empty
-        }
-
-
-{-| Encode an id-dict to a JSON value.
--}
-encode : Json.Coder a -> Json.Encoder (Iddict a)
-encode x =
-    Json.encode (coder x)
-
-
-{-| Get a value from the id-dict using its key.
--}
-get : Int -> Iddict a -> Maybe a
-get k (Iddict { dict }) =
-    Dict.get k dict
-
-
-{-| Insert a new value into the id-dict. Given that the id-dict generates its
-key, the function returns both the updated id-dict as the newly generated key.
-
-    x = empty |> insert "hello" -- ( 0, <Iddict with value "hello"> )
-
-    case x of
-        ( _, iddict ) ->
-            get 0 iddict -- Just "hello"
-
--}
-insert : a -> Iddict a -> ( Int, Iddict a )
-insert v (Iddict d) =
-    ( d.cursor
-    , Iddict { cursor = d.cursor + 1, dict = Dict.insert d.cursor v d.dict }
-    )
-
-
-{-| Determine if an id-dict is empty.
--}
-isEmpty : Iddict a -> Bool
-isEmpty (Iddict d) =
-    Dict.isEmpty d.dict
-
-
-{-| Get all of the keys from the id-dict, sorted from lowest to highest.
--}
-keys : Iddict a -> List Int
-keys (Iddict { dict }) =
-    Dict.keys dict
-
-
-{-| Map an existing value at a given key, if it exists. If it does not exist,
-the operation does nothing.
--}
-map : Int -> (a -> a) -> Iddict a -> Iddict a
-map k f (Iddict d) =
-    Iddict { d | dict = Dict.update k (Maybe.map f) d.dict }
-
-
-{-| Determine if a key is in an id-dict.
--}
-member : Int -> Iddict a -> Bool
-member k (Iddict d) =
-    k < d.cursor && Dict.member k d.dict
-
-
-{-| Remove a key-value pair from the id-dict. If the key is not found, no
-changes are made.
--}
-remove : Int -> Iddict a -> Iddict a
-remove k (Iddict d) =
-    Iddict { d | dict = Dict.remove k d.dict }
-
-
-{-| Create an id-dict with a single value.
--}
-singleton : a -> ( Int, Iddict a )
-singleton v =
-    insert v empty
-
-
-{-| Determine the number of key-value pairs in the id-dict.
--}
-size : Iddict a -> Int
-size (Iddict d) =
-    Dict.size d.dict
-
-
-{-| Get all of the values from an id-dict, in the order of their keys.
--}
-values : Iddict a -> List a
-values (Iddict { dict }) =
-    Dict.values dict
diff --git a/src/Internal/Tools/Json.elm b/src/Internal/Tools/Json.elm
index 28ccd8c..1a3116f 100644
--- a/src/Internal/Tools/Json.elm
+++ b/src/Internal/Tools/Json.elm
@@ -3,7 +3,7 @@ module Internal.Tools.Json exposing
     , Encoder, encode, Decoder, decode, Value
     , succeed, fail, andThen, lazy, map
     , Docs(..), RequiredField(..), toDocs
-    , list, listWithOne, slowDict, fastDict, fastIntDict, set, maybe
+    , list, listWithOne, slowDict, fastDict, fastIntDict, set, iddict, maybe
     , Field, field, parser
     , object2, object3, object4, object5, object6, object7, object8, object9, object10, object11
     )
@@ -49,7 +49,7 @@ module to build its encoders and decoders.
 
 ## Data types
 
-@docs list, listWithOne, slowDict, fastDict, fastIntDict, set, maybe
+@docs list, listWithOne, slowDict, fastDict, fastIntDict, set, iddict, maybe
 
 
 ## Objects
@@ -68,6 +68,7 @@ Once all fields are constructed, the user can create JSON objects.
 
 import Dict as SlowDict
 import FastDict
+import Iddict exposing (Iddict)
 import Internal.Config.Log as Log exposing (Log)
 import Internal.Config.Text as Text
 import Internal.Tools.DecodeExtra as D
@@ -141,6 +142,7 @@ type Docs
     = DocsBool
     | DocsDict Docs
     | DocsFloat
+    | DocsIddict Docs
     | DocsInt
     | DocsIntDict Docs
     | DocsLazy (() -> Docs)
@@ -467,6 +469,25 @@ float =
         }
 
 
+{-| Define an Iddict as defined in
+[noordstar/elm-iddict](https://package.elm-lang.org/packages/noordstar/elm-iddict/latest/).
+-}
+iddict : Coder a -> Coder (Iddict a)
+iddict (Coder old) =
+    Coder
+        { encoder = Iddict.encode old.encoder
+        , decoder =
+            D.andThen
+                (\( out, logs ) ->
+                    D.succeed out
+                        |> Iddict.decoder
+                        |> D.map (\o -> ( o, logs ))
+                )
+                old.decoder
+        , docs = DocsIddict old.docs
+        }
+
+
 {-| Define an int value.
 -}
 int : Coder Int
diff --git a/src/Internal/Values/Timeline.elm b/src/Internal/Values/Timeline.elm
index 9bded76..ea038a1 100644
--- a/src/Internal/Values/Timeline.elm
+++ b/src/Internal/Values/Timeline.elm
@@ -67,10 +67,10 @@ events!
 -}
 
 import FastDict as Dict exposing (Dict)
+import Iddict exposing (Iddict)
 import Internal.Config.Text as Text
 import Internal.Filter.Timeline as Filter exposing (Filter)
 import Internal.Tools.Hashdict as Hashdict exposing (Hashdict)
-import Internal.Tools.Iddict as Iddict exposing (Iddict)
 import Internal.Tools.Json as Json
 import Recursion
 import Recursion.Traverse
@@ -210,7 +210,7 @@ coder =
             { fieldName = "batches"
             , toField = \(Timeline t) -> t.batches
             , description = Text.fields.timeline.batches
-            , coder = Iddict.coder coderIBatch
+            , coder = Json.iddict coderIBatch
             }
         )
         (Json.field.required
@@ -411,8 +411,8 @@ connectIBatchToIToken (IBatchPTR bptr) pointer (Timeline tl) =
             Timeline
                 { tl
                     | batches =
-                        Iddict.map bptr
-                            (\batch -> { batch | end = pointer })
+                        Iddict.update bptr
+                            (Maybe.map (\batch -> { batch | end = pointer }))
                             tl.batches
                     , tokens =
                         Hashdict.map tptr
@@ -437,8 +437,8 @@ connectITokenToIBatch pointer (IBatchPTR bptr) (Timeline tl) =
                             (\token -> { token | starts = Set.insert bptr token.starts })
                             tl.tokens
                     , batches =
-                        Iddict.map bptr
-                            (\batch -> { batch | start = pointer })
+                        Iddict.update bptr
+                            (Maybe.map (\batch -> { batch | start = pointer }))
                             tl.batches
                 }
 
diff --git a/tests/Test/Tools/Iddict.elm b/tests/Test/Tools/Iddict.elm
deleted file mode 100644
index 708ecb7..0000000
--- a/tests/Test/Tools/Iddict.elm
+++ /dev/null
@@ -1,280 +0,0 @@
-module Test.Tools.Iddict exposing (..)
-
-import Expect
-import Fuzz exposing (Fuzzer)
-import Internal.Tools.Iddict as Iddict exposing (Iddict)
-import Internal.Tools.Json as Json
-import Json.Decode as D
-import Json.Encode as E
-import Test exposing (..)
-
-
-fuzzer : Fuzzer a -> Fuzzer (Iddict a)
-fuzzer fuz =
-    fuz
-        |> Fuzz.pair Fuzz.bool
-        |> Fuzz.list
-        |> Fuzz.map
-            (\items ->
-                List.foldl
-                    (\( rm, item ) dict ->
-                        case Iddict.insert item dict of
-                            ( key, d ) ->
-                                if rm then
-                                    Iddict.remove key d
-
-                                else
-                                    d
-                    )
-                    Iddict.empty
-                    items
-            )
-
-
-empty : Test
-empty =
-    describe "empty"
-        [ test "isEmpty"
-            (Iddict.empty
-                |> Iddict.isEmpty
-                |> Expect.equal True
-                |> always
-            )
-        , fuzz Fuzz.int
-            "No members"
-            (\i ->
-                Iddict.empty
-                    |> Iddict.member i
-                    |> Expect.equal False
-            )
-        , fuzz Fuzz.int
-            "Get gets Nothing"
-            (\i ->
-                Iddict.empty
-                    |> Iddict.get i
-                    |> Expect.equal Nothing
-            )
-        , test "Size = 0"
-            (Iddict.empty
-                |> Iddict.size
-                |> Expect.equal 0
-                |> always
-            )
-        , test "No keys"
-            (Iddict.empty
-                |> Iddict.keys
-                |> Expect.equal []
-                |> always
-            )
-        , test "No values"
-            (Iddict.empty
-                |> Iddict.values
-                |> Expect.equal []
-                |> always
-            )
-        , test "JSON encode -> decode -> empty"
-            (Iddict.empty
-                |> Iddict.encode Json.value
-                |> D.decodeValue (Iddict.decoder Json.value)
-                |> Result.map Tuple.first
-                |> Expect.equal (Ok Iddict.empty)
-                |> always
-            )
-        , test "JSON encode"
-            (Iddict.empty
-                |> Iddict.encode Json.value
-                |> E.encode 0
-                |> Expect.equal "{\"dict\":{}}"
-                |> always
-            )
-        , test "JSON decode"
-            ("{\"dict\":{}}"
-                |> D.decodeString (Iddict.decoder Json.value)
-                |> Result.map Tuple.first
-                |> Expect.equal (Ok Iddict.empty)
-                |> always
-            )
-        ]
-
-
-singleton : Test
-singleton =
-    let
-        singleFuzzer : Fuzzer (Iddict Int)
-        singleFuzzer =
-            Fuzz.map
-                (\i ->
-                    Iddict.singleton i
-                        |> Tuple.second
-                )
-                Fuzz.int
-    in
-    describe "singleton"
-        [ fuzz singleFuzzer
-            "not isEmpty"
-            (\single ->
-                single
-                    |> Iddict.isEmpty
-                    |> Expect.equal False
-            )
-        , fuzz Fuzz.int
-            "singleton == insert empty"
-            (\i ->
-                Iddict.empty
-                    |> Iddict.insert i
-                    |> Expect.equal (Iddict.singleton i)
-            )
-        , fuzz Fuzz.int
-            "First item is key 0"
-            (\i ->
-                Iddict.singleton i
-                    |> Tuple.first
-                    |> Expect.equal 0
-            )
-        , fuzz singleFuzzer
-            "Key 0 is member"
-            (\single ->
-                single
-                    |> Iddict.member 0
-                    |> Expect.equal True
-            )
-        , fuzz Fuzz.int
-            "Key 0 get returns Just value"
-            (\i ->
-                Iddict.singleton i
-                    |> Tuple.second
-                    |> Iddict.get 0
-                    |> Expect.equal (Just i)
-            )
-        , fuzz singleFuzzer
-            "Size == 1"
-            (\single ->
-                single
-                    |> Iddict.size
-                    |> Expect.equal 1
-            )
-        , fuzz Fuzz.int
-            "Only key 0"
-            (\i ->
-                Iddict.singleton i
-                    |> Tuple.second
-                    |> Iddict.keys
-                    |> Expect.equal [ 0 ]
-            )
-        , fuzz Fuzz.int
-            "Only value value"
-            (\i ->
-                Iddict.singleton i
-                    |> Tuple.second
-                    |> Iddict.values
-                    |> Expect.equal [ i ]
-            )
-        , fuzz singleFuzzer
-            "JSON encode -> decode -> singleton"
-            (\single ->
-                single
-                    |> Iddict.encode Json.int
-                    |> D.decodeValue (Iddict.decoder Json.int)
-                    |> Result.map Tuple.first
-                    |> Expect.equal (Ok single)
-            )
-        , fuzz Fuzz.int
-            "JSON encode"
-            (\i ->
-                Iddict.singleton i
-                    |> Tuple.second
-                    |> Iddict.encode Json.int
-                    |> E.encode 0
-                    |> Expect.equal ("{\"cursor\":1,\"dict\":{\"0\":" ++ String.fromInt i ++ "}}")
-            )
-        , fuzz Fuzz.int
-            "JSON decode"
-            (\i ->
-                ("{\"cursor\":1,\"dict\":{\"0\":" ++ String.fromInt i ++ "}}")
-                    |> D.decodeString (Iddict.decoder Json.int)
-                    |> Result.map Tuple.first
-                    |> Tuple.pair 0
-                    |> Expect.equal (Iddict.singleton i |> Tuple.mapSecond Ok)
-            )
-        ]
-
-
-insert : Test
-insert =
-    describe "insert"
-        [ fuzz2 (fuzzer Fuzz.int)
-            Fuzz.int
-            "Add something"
-            (\d i ->
-                case Iddict.insert i d of
-                    ( key, dict ) ->
-                        dict
-                            |> Iddict.get key
-                            |> Expect.equal (Just i)
-            )
-        , fuzz2 (fuzzer Fuzz.int)
-            Fuzz.int
-            "Never isEmpty"
-            (\d i ->
-                Iddict.insert i d
-                    |> Tuple.second
-                    |> Iddict.isEmpty
-                    |> Expect.equal False
-            )
-        , fuzz2 (fuzzer Fuzz.int)
-            Fuzz.int
-            "New key"
-            (\d i ->
-                case Iddict.insert i d of
-                    ( key, dict ) ->
-                        dict
-                            |> Iddict.remove key
-                            |> Iddict.insert i
-                            |> (\( newKey, _ ) ->
-                                    Expect.notEqual key newKey
-                               )
-            )
-        , fuzz2 (fuzzer Fuzz.int)
-            Fuzz.int
-            "New dict"
-            (\d i ->
-                case Iddict.insert i d of
-                    ( key, dict ) ->
-                        dict
-                            |> Iddict.remove key
-                            |> Iddict.insert i
-                            |> (\( _, newDict ) ->
-                                    Expect.notEqual dict newDict
-                               )
-            )
-        , fuzz2 (fuzzer Fuzz.int)
-            Fuzz.int
-            "Inserted value is member"
-            (\d i ->
-                case Iddict.insert i d of
-                    ( key, dict ) ->
-                        dict
-                            |> Iddict.member key
-                            |> Expect.equal True
-            )
-        , fuzz2 (fuzzer Fuzz.int)
-            Fuzz.int
-            "Get inserted value"
-            (\d i ->
-                case Iddict.insert i d of
-                    ( key, dict ) ->
-                        dict
-                            |> Iddict.get key
-                            |> Expect.equal (Just i)
-            )
-        , fuzz2 (fuzzer Fuzz.int)
-            Fuzz.int
-            "size = size + 1"
-            (\d i ->
-                case Iddict.insert i d of
-                    ( _, dict ) ->
-                        Expect.equal
-                            (Iddict.size dict)
-                            (Iddict.size d + 1)
-            )
-        ]