diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,14 @@
+## [2.0.0](https://github.com/haskell-github-trust/effectful-cli/compare/1.0.2...2.0.0) (2026-10-26)
+
+### ⚠ BREAKING CHANGES
+
+* use Text instead of String where relevant
+
+### Features
+
+* support generic `Foldable` and `Traversable` structures ([64382ea](https://github.com/haskell-github-trust/effectful-cli/commit/64382ea50c9fde7fae8991afe74ae4e223c16333))
+* use Text instead of String where relevant ([52450e3](https://github.com/haskell-github-trust/effectful-cli/commit/52450e36dd017d208ea5f9675cb89bfc39aee56e))
+
 ## [1.0.2](https://github.com/haskell-github-trust/effectful-cli/compare/1.0.1...1.0.2) (2026-10-26)
 
 ## [1.0.1](https://github.com/haskell-github-trust/effectful-cli/compare/1.0.0...1.0.1) (2026-10-25)
diff --git a/effectful-cli.cabal b/effectful-cli.cabal
--- a/effectful-cli.cabal
+++ b/effectful-cli.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           effectful-cli
-version:        0.1.0.2
+version:        0.2.0.0
 synopsis:       CLI helpers for the effectful ecosystem
 description:    Please see the README at https://github.com/haskell-github-trust/effectful-cli
 category:       CLI
diff --git a/src/Data/Error/CLI.hs b/src/Data/Error/CLI.hs
--- a/src/Data/Error/CLI.hs
+++ b/src/Data/Error/CLI.hs
@@ -1,27 +1,31 @@
+{-# LANGUAGE OverloadedStrings #-}
+
 -- | Errors common to CLI applications.
 module Data.Error.CLI (
   CLIError (..),
   displayCLIError,
 ) where
 
+import Data.Text (Text)
+
 -- | Errors raised by CLI helpers.
 --
 -- @since 0.1.0.0
 data CLIError
   = -- | Invalid user input.
-    InputError String
+    InputError Text
   | -- | Requested item does not exist.
-    NotFoundError String
+    NotFoundError Text
   | -- | Feature not implemented yet.
-    NotImplemented String
+    NotImplemented Text
   | -- | User declined a confirmation, with an optional reason.
-    UserCanceled (Maybe String)
+    UserCanceled (Maybe Text)
   deriving (Eq, Show)
 
 -- | Render a 'CLIError' as a human-readable message.
 --
 -- @since 0.1.0.0
-displayCLIError :: CLIError -> String
+displayCLIError :: CLIError -> Text
 displayCLIError (InputError s) = "input error: " <> s
 displayCLIError (NotFoundError s) = "not found: " <> s
 displayCLIError (NotImplemented s) = "not implemented: " <> s
diff --git a/src/Effectful/CLI/Conc.hs b/src/Effectful/CLI/Conc.hs
--- a/src/Effectful/CLI/Conc.hs
+++ b/src/Effectful/CLI/Conc.hs
@@ -14,6 +14,8 @@
   batchConcurrentlyWithIndex_,
 ) where
 
+import Data.Foldable (toList)
+import Data.Traversable (mapAccumL)
 import Effectful (Eff, (:>))
 import Effectful.Concurrent.Async (
   Concurrent,
@@ -52,10 +54,11 @@
 -- @since 0.1.0.0
 batchConcurrently
   :: Concurrent :> es
+  => Traversable t
   => Int
   -> (a -> Eff es b)
-  -> [a]
-  -> Eff es [b]
+  -> t a
+  -> Eff es (t b)
 batchConcurrently = pooledMapConcurrentlyN
 
 -- | Like 'batchConcurrently', discarding results.
@@ -63,9 +66,10 @@
 -- @since 0.1.0.0
 batchConcurrently_
   :: Concurrent :> es
+  => Foldable f
   => Int
   -> (a -> Eff es b)
-  -> [a]
+  -> f a
   -> Eff es ()
 batchConcurrently_ = pooledMapConcurrentlyN_
 
@@ -74,19 +78,22 @@
 -- @since 0.1.0.0
 batchConcurrentlyWithIndex
   :: Concurrent :> es
+  => Traversable t
   => Int
   -> (Int -> a -> Eff es b)
-  -> [a]
-  -> Eff es [b]
-batchConcurrentlyWithIndex n f = batchConcurrently n (uncurry f) . zip [1 ..]
+  -> t a
+  -> Eff es (t b)
+batchConcurrentlyWithIndex n f =
+  batchConcurrently n (uncurry f) . snd . mapAccumL (\i x -> (i + 1, (i, x))) 1
 
 -- | Like 'batchConcurrentlyWithIndex', discarding results.
 --
 -- @since 0.1.0.0
 batchConcurrentlyWithIndex_
   :: Concurrent :> es
+  => Foldable f
   => Int
   -> (Int -> a -> Eff es b)
-  -> [a]
+  -> f a
   -> Eff es ()
-batchConcurrentlyWithIndex_ n f = batchConcurrently_ n (uncurry f) . zip [1 ..]
+batchConcurrentlyWithIndex_ n f = batchConcurrently_ n (uncurry f) . zip [1 ..] . toList
diff --git a/src/Effectful/CLI/IO.hs b/src/Effectful/CLI/IO.hs
--- a/src/Effectful/CLI/IO.hs
+++ b/src/Effectful/CLI/IO.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE AllowAmbiguousTypes #-}
+{-# LANGUAGE OverloadedStrings #-}
 
 -- | Terminal output, prompts and confirmations.
 module Effectful.CLI.IO (
@@ -18,14 +19,18 @@
 import Control.Monad (unless, void, when)
 import Data.CLI.Class (CLIConfig (..))
 import Data.Error.CLI (CLIError (..))
+import Data.Foldable (toList)
 import Data.Functor (($>))
 import Data.Maybe (fromMaybe)
+import Data.Text (Text)
+import Data.Text qualified as T
+import Data.Text.IO qualified as T
 import Data.Void (Void)
 import Effectful (Eff, IOE, liftIO, (:>))
 import Effectful.Error.Static (Error, throwError)
 import Effectful.Process (Process, callProcess)
 import Effectful.Reader.Static (Reader, ask)
-import System.IO (hFlush, hPutStr, stderr)
+import System.IO (hFlush, stderr)
 import Text.Layout.Table (columnHeaderTableS, def, rowsG, tableString, titlesH, unicodeS)
 import Text.Megaparsec (Parsec, eof, errorBundlePretty, runParser, (<|>))
 import Text.Megaparsec.Char (string')
@@ -35,44 +40,45 @@
 -- | Print to stdout without a trailing newline.
 --
 -- @since 0.1.0.0
-printOutput :: IOE :> es => String -> Eff es ()
-printOutput = liftIO . putStr
+printOutput :: IOE :> es => Text -> Eff es ()
+printOutput = liftIO . T.putStr
 
 -- | Print to stdout with a trailing newline.
 --
 -- @since 0.1.0.0
-printOutputLn :: IOE :> es => String -> Eff es ()
-printOutputLn = liftIO . putStrLn
+printOutputLn :: IOE :> es => Text -> Eff es ()
+printOutputLn = liftIO . T.putStrLn
 
 -- | Print to stderr without a trailing newline.
 --
 -- @since 0.1.0.0
-printError :: IOE :> es => String -> Eff es ()
-printError = liftIO . hPutStr stderr
+printError :: IOE :> es => Text -> Eff es ()
+printError = liftIO . T.hPutStr stderr
 
 -- | Print lines to stdout, each followed by a newline.
 --
 -- @since 0.1.0.0
-printLines :: IOE :> es => [String] -> Eff es ()
-printLines = printOutput . unlines
+printLines :: IOE :> es => Foldable f => f Text -> Eff es ()
+printLines = printOutput . T.unlines . toList
 
 -- | Read a line from stdin after printing an optional prompt to stderr.
 --
 -- @since 0.1.0.0
-prompt :: IOE :> es => Maybe String -> Eff es String
+prompt :: IOE :> es => Maybe Text -> Eff es Text
 prompt p = liftIO $ do
-  hPutStr stderr (fromMaybe "" p <> "> ")
+  T.hPutStr stderr (fromMaybe "" p <> "> ")
   hFlush stderr
-  getLine
+  T.getLine
 
 -- | Prompt and parse the answer, throwing 'InputError' on parse failure.
 --
 -- @since 0.1.0.0
 prompt'
-  :: Error CLIError :> es => IOE :> es => Maybe String -> Parsec Void String a -> Eff es a
+  :: Error CLIError :> es => IOE :> es => Maybe Text -> Parsec Void Text a -> Eff es a
 prompt' p parser =
   prompt p
-    >>= either (throwError . InputError . errorBundlePretty) pure . runParser parser "prompt"
+    >>= either (throwError . InputError . T.pack . errorBundlePretty) pure
+      . runParser parser "prompt"
 
 -- | Ask for confirmation; @y@, @yes@ or an empty answer mean yes.
 --
@@ -112,16 +118,20 @@
 chooseItem
   :: Error CLIError :> es
   => IOE :> es
-  => String -> [String] -> (a -> [String]) -> [a] -> Eff es a
-chooseItem name _ _ [] = throwError (NotFoundError ("no item found for " <> name))
-chooseItem _ _ _ [x] = pure x
-chooseItem name headers row xs = do
-  let hs = "#" : headers
-      rows = zipWith (\i x -> show i : row x) [1 :: Int ..] xs
-  printOutputLn
-    (tableString (columnHeaderTableS (fmap (const def) hs) unicodeS (titlesH hs) [rowsG rows]))
-  i <- prompt' (Just name) (signed (pure ()) decimal)
-  either throwError (pure . (xs !!)) (resolveIndex (length xs) i)
+  => Foldable f
+  => Text -> [Text] -> (a -> [Text]) -> f a -> Eff es a
+chooseItem name headers row = go . toList
+ where
+  go [] = throwError (NotFoundError ("no item found for " <> name))
+  go [x] = pure x
+  go xs = pick xs
+  pick xs = do
+    let hs = "#" : fmap T.unpack headers
+        rows = zipWith (\i x -> show i : fmap T.unpack (row x)) [1 :: Int ..] xs
+    printOutputLn . T.pack $
+      tableString (columnHeaderTableS (fmap (const def) hs) unicodeS (titlesH hs) [rowsG rows])
+    i <- prompt' (Just name) (signed (pure ()) decimal)
+    either throwError (pure . (xs !!)) (resolveIndex (length xs) i)
 
 -- | Turn a 1-based (or negative, from the end) user index into a 0-based one.
 --
@@ -130,4 +140,4 @@
 resolveIndex len i
   | i >= 1 && i <= len = Right (i - 1)
   | i <= -1 && i >= -len = Right (len + i)
-  | otherwise = Left (InputError (printf "index %d out of bounds" i))
+  | otherwise = Left (InputError (T.pack $ printf "index %d out of bounds" i))
diff --git a/test/Spec.hs b/test/Spec.hs
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE OverloadedStrings #-}
+
 import Data.CLI.Impl (fromParsec)
 import Data.Error.CLI (CLIError (..), displayCLIError)
 import Effectful (runEff)