diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,56 @@
+# Changelog
+
+## Unreleased
+
+## 1.3.0.0
+
+### JsonEither now takes a type-level list
+
+`JsonEither` now accepts a type-level list of specs (`JsonEither '[a, b, c]`)
+instead of two arguments (`JsonEither a b`), so sum types with many branches
+no longer require a binary tree of nested `JsonEither`s. The structural type
+for `JsonEither` is nested `Either`: two or more branches map to
+`Either (JStruct env a) (Either (JStruct env b) ...)`; a single branch maps
+to `JStruct env spec` (no sum wrapper). Use `Left`/`Right` for construction
+and pattern matching.
+
+#### Migration guide
+
+**Specs (example: four alternatives)**
+
+Before:
+
+```
+JsonEither (JsonEither (JsonEither specA specB) specC) specD
+```
+
+After:
+
+```
+JsonEither '[specA, specB, specC, specD]
+```
+
+**Patterns/construction**
+
+**Note:** The only difference in the pattern/construction may be how
+the `Either`s are nested. The two examples below represent the same
+four alternatives with different `Left`/`Right` nesting; the JSON and
+types are equivalent.
+
+Before (four branches):
+
+```
+Left (Left (Left val))
+Left (Left (Right val))
+Left (Right val)
+Right val
+```
+
+After (same nesting with `Left`/`Right`; one branch = no wrapper):
+
+```
+Left val
+Right (Left val)
+Right (Right (Left val))
+Right (Right (Right val))
+```
diff --git a/json-spec.cabal b/json-spec.cabal
--- a/json-spec.cabal
+++ b/json-spec.cabal
@@ -1,6 +1,6 @@
 cabal-version:       3.0
 name:                json-spec
-version:             1.2.0.0
+version:             1.3.0.0
 synopsis:            Type-level JSON specification
 maintainer:          rick@owensmurray.com
 description:         See the README at: https://github.com/owensmurray/json-spec#json-spec
@@ -9,9 +9,10 @@
 license-file:        LICENSE
 author:              Rick Owens
 category:            JSON
-copyright:           2025 Owens Murray, LLC.
+copyright:           2026 Owens Murray, LLC.
 build-type:          Simple
-extra-source-files:
+extra-doc-files:
+  CHANGELOG.md
   README.md
   LICENSE
 
diff --git a/src/Data/JsonSpec/Spec.hs b/src/Data/JsonSpec/Spec.hs
--- a/src/Data/JsonSpec/Spec.hs
+++ b/src/Data/JsonSpec/Spec.hs
@@ -33,7 +33,8 @@
 import Data.Time (UTCTime)
 import GHC.Records (HasField(getField))
 import GHC.TypeLits (KnownSymbol, Symbol, symbolVal)
-import Prelude (Maybe(Just, Nothing), ($), Bool, Either, Eq, Int, Show)
+import qualified GHC.TypeError as GE
+import Prelude (Either, Maybe(Just, Nothing), ($), Bool, Eq, Int, Show)
 
 
 {-|
@@ -74,11 +75,19 @@
       >     Required "nullableProperty" (JsonNullable JsonString)
       >   ]
     -}
-  JsonEither :: Specification -> Specification -> Specification
+  JsonEither :: [Specification] -> Specification
     {-^
-      One of two different specifications. Corresponds to json-schema
-      "oneOf". Useful for encoding sum types. E.g:
+      One of several different specifications. Corresponds to json-schema
+      "oneOf". Useful for encoding sum types.
 
+      Takes a type-level list of specs. In the structural representation
+      ('JStruct'), `JsonEither` maps to nested `Either`: two or more
+      branches become @Either (JStruct env a) (Either (JStruct env b) ...)@;
+      a single branch maps to @JStruct env spec@ (no sum wrapper). Use
+      `Left`/`Right` for construction and pattern matching.
+
+      Example:
+
       > data MyType
       >   = Foo Text
       >   | Bar Int
@@ -86,27 +95,37 @@
       > instance HasJsonEncodingSpec MyType where
       >   type EncodingSpec MyType =
       >     JsonEither
-      >       (
+      >       '[
       >         JsonObject '[
       >           Required "tag" (JsonTag "foo"),
       >           Required "content" JsonString
+      >         ],
+      >         JsonObject '[
+      >           Required "tag" (JsonTag "bar"),
+      >           Required "content" JsonInt
+      >         ],
+      >         JsonObject '[
+      >           Required "tag" (JsonTag "baz"),
+      >           Required "content" JsonDateTime
       >         ]
-      >       )
-      >       (
-      >         JsonEither
-      >           (
-      >             JsonObject '[
-      >               Required "tag" (JsonTag "bar"),
-      >               Required "content" JsonInt
-      >             ]
-      >           )
-      >           (
-      >             JsonObject '[
-      >               Required "tag" (JsonTag "baz"),
-      >               Required "content" JsonDateTime
-      >             ]
-      >           )
-      >       )
+      >       ]
+      >
+      >   toJSONStructure = \case
+      >     Foo t ->
+      >       Left
+      >         ( Field @"tag" (Tag @"foo")
+      >         , (Field @"content" t, ())
+      >         )
+      >     Bar i ->
+      >       Right (Left
+      >         ( Field @"tag" (Tag @"bar")
+      >         , (Field @"content" i, ())
+      >         )
+      >     Baz dt ->
+      >       Right (Right
+      >         ( Field @"tag" (Tag @"baz")
+      >         , (Field @"content" dt, ())
+      >         )
     -}
   JsonTag :: Symbol -> Specification
     {-^ A constant string value -}
@@ -290,6 +309,19 @@
   PushAll (e : more) b = PushAll more (e : b)
 
 
+{-|
+  Structural type for `JsonEither`: nested `Either` for two or more branches,
+  or the lone branch type for a singleton list. Empty list is disallowed.
+-}
+type family EitherJStruct (env :: Env) (specs :: [Specification]) :: Type where
+  EitherJStruct _env '[] =
+    GE.TypeError (GE.Text "JsonEither requires at least one branch")
+  EitherJStruct env '[spec] =
+    JStruct env spec
+  EitherJStruct env (a ': b ': more) =
+    Either (JStruct env a) (EitherJStruct env (b ': more))
+
+
 type family
   JStruct
     (env :: Env)
@@ -312,8 +344,8 @@
     JStruct env JsonInt = Int
     JStruct env (JsonArray spec) = [JStruct env spec]
     JStruct env JsonBool = Bool
-    JStruct env (JsonEither left right) =
-      Either (JStruct env left) (JStruct env right)
+    JStruct env (JsonEither specs) =
+      EitherJStruct env specs
     JStruct env (JsonTag tag) = Tag tag
     JStruct env JsonDateTime = UTCTime
     JStruct env (JsonNullable spec) = Maybe (JStruct env spec)
diff --git a/test/jsonspec.hs b/test/jsonspec.hs
--- a/test/jsonspec.hs
+++ b/test/jsonspec.hs
@@ -6,8 +6,8 @@
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE OverloadedRecordDot #-}
 {-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE TypeAbstractions #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE UndecidableInstances #-}
@@ -19,7 +19,6 @@
   be disabled individually, but then we re-enable the specific warnings
   we most care about.
 -}
-{-# OPTIONS_GHC -Wwarn #-}
 {-# OPTIONS_GHC -Werror=missing-import-lists #-}
 
 module Main (main) where
@@ -37,7 +36,8 @@
     , JsonLet, JsonNullable, JsonNum, JsonObject, JsonRaw, JsonRef, JsonString
     , JsonTag
     )
-  , Tag(Tag), (:::), (::?), eitherDecode, encode, unField
+  , Tag(Tag), (:::), (::?), eitherDecode
+  , encode, unField
   )
 import Data.Proxy (Proxy(Proxy))
 import Data.Scientific (Scientific)
@@ -690,16 +690,18 @@
 instance HasJsonEncodingSpec TestSum where
   type EncodingSpec TestSum =
     JsonEither
-      (JsonObject '[
-        Required "tag" (JsonTag "a"),
-        Required "content" (JsonObject [
-          Required "int-field" JsonInt,
-          Required "txt-field" JsonString
-        ])
-      ])
-      (JsonObject '[
-        Required "tag" (JsonTag "b")
-      ])
+      '[
+        JsonObject '[
+          Required "tag" (JsonTag "a"),
+          Required "content" (JsonObject [
+            Required "int-field" JsonInt,
+            Required "txt-field" JsonString
+          ])
+        ],
+        JsonObject '[
+          Required "tag" (JsonTag "b")
+        ]
+      ]
   toJSONStructure = \case
     TestA i t ->
       Left