diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,3 @@
+# 0.1.0.0 (2021-03-21)
+
+Initial release.
diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,190 @@
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+
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+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
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+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
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+   END OF TERMS AND CONDITIONS
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+   Copyright 2021 Leo Zhang
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
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+
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+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,54 @@
+# bottom-hs
+
+[![Build and test](https://github.com/bottom-software-foundation/bottom-hs/actions/workflows/main.yml/badge.svg)](https://github.com/bottom-software-foundation/bottom-hs/actions/workflows/main.yml)
+[![Hackage](https://img.shields.io/hackage/v/bottom)](https://hackage.haskell.org/package/bottom)
+[![Hackage-Deps](https://img.shields.io/hackage-deps/v/bottom)](https://hackage.haskell.org/package/bottom)
+
+Based off of the hilarious [bottom-rs](https://github.com/bottom-software-foundation/bottom-rs), built to the [Bottom spec](https://github.com/bottom-software-foundation/spec).
+
+![,,,,,,,,,](https://cdn.discordapp.com/attachments/644479051918082050/799905088541425664/bottom.jpg)
+
+## Using the CLI
+
+```sh
+$ cabal run bottom -- --help
+
+Bottom translator 0.1.0
+
+Usage: bottom ((-b|--bottomify) | (-r|--regress) | (-V|--version)) <TEXT>
+  Fantastic (maybe) CLI for translating between bottom and human-readable text
+
+Available options:
+  -b,--bottomify           Translate text to bottom
+  -r,--regress             Translate bottom to human-readable text (futile)
+  -V,--version             Prints version information
+  -h,--help                Show this help text
+```
+```sh
+$ cabal run bottom -- --regress 🫂✨✨🥺,,👉👈💖💖✨✨🥺,,,,👉👈💖💖✨✨✨✨👉👈🫂✨✨🥺,,👉👈💖💖✨✨✨👉👈💖💖✨✨✨✨🥺,,👉👈🫂✨✨🥺,,👉👈💖💖✨✨🥺,,,,👉👈💖💖💖✨✨🥺,👉👈🫂✨✨🥺,,👉👈💖💖✨✨✨👉👈 💖💖✨✨✨✨👉👈
+がんばれ
+```
+```sh
+$ cabal run bottom -- --bottomify Test
+💖✨✨✨,,,,👉👈💖💖,👉👈💖💖✨🥺👉👈💖💖✨🥺,👉👈
+```
+
+## Usage as a library
+
+See the generate Haddock documentation in Hackage for module documentation.
+
+## Development
+
+Useful commands:
+
+- `cabal run bottom -- --help`: Runs the CLI.
+- `cabal repl`: Run the library in the REPL. Loads `Data.Encoding.Bottom` with `-XOverloadedStrings` by default (see `.ghci`).
+- `cabal test --enable-coverage`: Run tests, with test coverage.
+- `cabal bench`: Run benchmarks.
+- `cabal haddock --haddock-all --enable-documentation`: Generate documentation.
+- `ormolu --mode inplace $(find . -path ./dist-newstyle -prune -false -o -type f -name '*.hs')`: Format code (see [`ormolu`](https://github.com/tweag/ormolu)).
+- `cabal-fmt -i bottom.cabal`: Format `.cabal` file (see [`cabal-fmt`](https://github.com/phadej/cabal-fmt)).
+
+## License
+
+Apache 2.
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,6 @@
+module Main (main) where
+
+import Distribution.Simple
+
+main :: IO ()
+main = defaultMain
diff --git a/bench/Main.hs b/bench/Main.hs
new file mode 100644
--- /dev/null
+++ b/bench/Main.hs
@@ -0,0 +1,57 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module Main (main) where
+
+import Control.DeepSeq (NFData)
+import Criterion.Main (Benchmark, bench, bgroup, defaultMain, nf)
+import Data.Encoding.Bottom (decode, encode)
+import Data.Text (Text)
+import qualified Data.Text as T
+
+main :: IO ()
+main =
+  defaultMain
+    [ bgroup "encoding" encodeBenches,
+      bgroup "decoding" decodeBenches
+    ]
+  where
+    -- Taken from https://github.com/bottom-software-foundation/bottom-rs/blob/need_top/bench/src/bench.rs
+    examples :: [(String, Text)]
+    examples =
+      [ ("single", "a"),
+        ("short", "abcd"),
+        ( "long",
+          T.pack $
+            unlines
+              [ "What the fuck did you just fucking say about me, you",
+                "little bitch? I’ll have you know I graduated top of my class in the Navy",
+                "Seals, and I’ve been involved in secret raids on Al-Quaeda, and I have over",
+                "300 confirmed kills. I am trained in gorilla warfare and I’m the top sniper",
+                "in the entire US armed forces. You are nothing to me but just another",
+                "target. I will wipe you out with precision the likes of which has never been",
+                "seen before on this Earth, mark my words. You think you can get away with",
+                "saying shit to me over the Internet? Think again, fucker. As we speak I am",
+                "contacting my network of spies across the USA and your IP is being traced",
+                "right now so you better prepare for the storm, maggot. The storm that wipes",
+                "out the pathetic little thing you call your life. You’re fucking dead, kid.",
+                "I can be anywhere, anytime, and I can kill you in over seven hundred ways,",
+                "and that’s just with my bare hands. Not only am I extensively trained in",
+                "unarmed combat, but I have access to the entire arsenal of the United States",
+                "Marine Corps and I will use it to its full extent to wipe your ass off the",
+                "face of the continent, you little shit. If only you could have known what",
+                "unholy retribution your little “clever” comment was about to bring down upon",
+                "you, maybe you would have held your tongue. You didn’t, and now you’re",
+                "paying the price, you goddamn idiot. I will shit all over you and you will",
+                "drown in it. You’re fucking dead, kiddo."
+              ]
+        )
+      ]
+
+    makeBench :: (NFData b) => (a -> b) -> (Text -> a) -> (String, Text) -> Benchmark
+    makeBench f transform (name, input) = bench name $ nf f $ transform input
+
+    encodeBenches :: [Benchmark]
+    encodeBenches = makeBench encode id <$> examples
+
+    decodeBenches :: [Benchmark]
+    decodeBenches = makeBench decode encode <$> examples
diff --git a/bottom.cabal b/bottom.cabal
new file mode 100644
--- /dev/null
+++ b/bottom.cabal
@@ -0,0 +1,91 @@
+cabal-version:      3.0
+name:               bottom
+version:            0.1.0.0
+synopsis:           Encoding and decoding for the Bottom spec.
+description:
+  Encoding and decoding for the [Bottom spec](https://github.com/bottom-software-foundation/spec).
+
+license:            Apache-2.0
+license-file:       LICENSE
+author:             Leo Zhang
+maintainer:         leo@leozhang.me
+copyright:          2021 Leo Zhang
+category:           Codec
+build-type:         Simple
+homepage:           https://github.com/bottom-software-foundation/bottom-hs
+bug-reports:
+  https://github.com/bottom-software-foundation/bottom-hs/issues
+
+tested-with:        GHC ==8.10.4
+extra-source-files:
+  CHANGELOG.md
+  README.md
+
+source-repository head
+  type:     git
+  location: git://github.com/bottom-software-foundation/bottom-hs.git
+
+common lang
+  build-depends:    base ^>=4.14
+  default-language: Haskell2010
+  ghc-options:
+    -Wall -Wincomplete-uni-patterns -Wcompat
+    -Wincomplete-record-updates -Wmissing-home-modules
+    -Wmissing-export-lists -Wredundant-constraints
+
+common deps
+  build-depends:
+    , bytestring  ^>=0.11.1.0
+    , text        ^>=1.2.4.1
+
+library
+  import:          lang
+  import:          deps
+  hs-source-dirs:  src
+
+  -- cabal-fmt: expand src
+  exposed-modules: Data.Encoding.Bottom
+  build-depends:
+    , deepseq     ^>=1.4.4.0
+    , megaparsec  ^>=9.0.1
+
+test-suite tests
+  import:         lang
+  import:         deps
+  type:           exitcode-stdio-1.0
+  hs-source-dirs: test
+  main-is:        Main.hs
+
+  -- cabal-fmt: expand test -Main
+  other-modules:
+  build-depends:
+    , bottom
+    , hspec       ^>=2.7.8
+    , QuickCheck  ^>=2.14.2
+
+benchmark bench
+  import:         lang
+  import:         deps
+  type:           exitcode-stdio-1.0
+  hs-source-dirs: bench
+  main-is:        Main.hs
+
+  -- cabal-fmt expand bench -Main
+  other-modules:
+  build-depends:
+    , bottom
+    , criterion  ^>=1.5.9.0
+    , deepseq    ^>=1.4.4.0
+
+executable bottom
+  import:         lang
+  import:         deps
+  ghc-options:    -threaded -with-rtsopts=-N
+  hs-source-dirs: cmd/bottom
+  main-is:        Main.hs
+
+  -- cabal-fmt: expand cmd/bottom -Main
+  other-modules:
+  build-depends:
+    , bottom
+    , optparse-applicative  ^>=0.16.1.0
diff --git a/cmd/bottom/Main.hs b/cmd/bottom/Main.hs
new file mode 100644
--- /dev/null
+++ b/cmd/bottom/Main.hs
@@ -0,0 +1,71 @@
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module Main (main) where
+
+import Data.Encoding.Bottom (decode', encode, unBottom)
+import Data.Text (Text)
+import qualified Data.Text as T
+import Data.Text.Encoding (decodeUtf8, encodeUtf8)
+import Options.Applicative
+  ( Parser,
+    ParserInfo,
+    argument,
+    execParser,
+    flag',
+    fullDesc,
+    header,
+    help,
+    helper,
+    info,
+    long,
+    metavar,
+    progDesc,
+    short,
+    str,
+    (<**>),
+    (<|>),
+  )
+
+version :: String
+version = "0.1.0"
+
+data Command
+  = Bottomify
+  | Regress
+  | Version
+  deriving (Show)
+
+commandParser :: Parser Command
+commandParser = bottomifyParser <|> regressParser <|> versionParser
+  where
+    bottomifyParser = flag' Bottomify $ long "bottomify" <> short 'b' <> help "Translate text to bottom"
+    regressParser = flag' Regress $ long "regress" <> short 'r' <> help "Translate bottom to human-readable text (futile)"
+    versionParser = flag' Version $ long "version" <> short 'V' <> help "Prints version information"
+
+data Options = Options
+  { mode :: Command,
+    text :: Text
+  }
+  deriving (Show)
+
+optionsParser :: Parser Options
+optionsParser = Options <$> commandParser <*> textParser
+  where
+    textParser = argument str (metavar "<TEXT>")
+
+opts :: ParserInfo Options
+opts =
+  info
+    (optionsParser <**> helper)
+    $ fullDesc <> progDesc "Fantastic (maybe) CLI for translating between bottom and human-readable text" <> header ("Bottom translator " <> version)
+
+main :: IO ()
+main = do
+  Options {mode, text} <- execParser opts
+  case mode of
+    Version -> putStrLn $ "Bottom translator " <> version
+    Bottomify -> putStrLn $ T.unpack $ decodeUtf8 $ unBottom $ encode text
+    Regress -> case decode' $ encodeUtf8 text of
+      Right decoded -> putStrLn $ T.unpack decoded
+      Left err -> putStrLn $ T.unpack err
diff --git a/src/Data/Encoding/Bottom.hs b/src/Data/Encoding/Bottom.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Encoding/Bottom.hs
@@ -0,0 +1,155 @@
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE StrictData #-}
+
+-- | Encodes and decodes 'Text's to 'Bottom's. For details, see the
+-- [Bottom spec](https://github.com/bottom-software-foundation/spec).
+module Data.Encoding.Bottom
+  ( Bottom,
+    unBottom,
+    encode,
+    decode,
+    decode',
+  )
+where
+
+import Control.DeepSeq (NFData)
+import Control.Monad (void)
+import Data.Bits (zeroBits)
+import Data.ByteString (ByteString)
+import qualified Data.ByteString as BS
+import qualified Data.Foldable as F
+import Data.List (unfoldr)
+import Data.List.NonEmpty (NonEmpty (..))
+import qualified Data.List.NonEmpty as NE
+import Data.Text (Text)
+import qualified Data.Text as T
+import Data.Text.Encoding (decodeUtf8, encodeUtf8)
+import Data.Void (Void)
+import Data.Word (Word8)
+import Text.Megaparsec (Parsec, Token, chunk, eof, manyTill, runParser, someTill, (<|>))
+import Text.Megaparsec.Error (ErrorItem (..), ParseError (..), ParseErrorBundle (..), errorBundlePretty)
+
+-- | A 'Bottom' is a wrapper around well-formed, Bottom-encoded 'ByteString'.
+-- Its instances are derived from those of 'ByteString'.
+newtype Bottom = Bottom ByteString
+  deriving (Show, Eq, Ord, Semigroup, Monoid, NFData)
+
+-- | 'unBottom' unwraps the underlying 'ByteString'.
+unBottom :: Bottom -> ByteString
+unBottom (Bottom bs) = bs
+
+-- Value characters for encoding.
+singleton :: Char -> ByteString
+singleton = encodeUtf8 . T.singleton
+
+twoHundred :: ByteString
+twoHundred = singleton '\x1FAC2'
+
+fifty :: ByteString
+fifty = singleton '\x1F496'
+
+ten :: ByteString
+ten = singleton '\x2728'
+
+five :: ByteString
+five = singleton '\x1F97A'
+
+one :: ByteString
+one = singleton '\x002C'
+
+zero :: ByteString
+zero = encodeUtf8 $ T.pack ['\x2764', '\xFE0F']
+
+separator :: ByteString
+separator = encodeUtf8 $ T.pack ['\x1F449', '\x1F448']
+
+-- Decoding functions.
+
+-- | 'decode' decodes a 'Bottom' into its corresponding Unicode 'Text'.
+decode :: Bottom -> Text
+decode (Bottom bs) = case decode' bs of
+  Right r -> r
+  Left err -> error "Data.Encoding.Bottom.decode: malformed Bottom: " <> err
+
+type Parser = Parsec Void ByteString
+
+-- | 'decode'' decodes an arbitrary Bottom-encoded 'ByteString' into a 'Text',
+-- or returns a parse error if the 'ByteString' is malformed.
+decode' :: ByteString -> Either Text Text
+decode' bs = case runParser bottomParser "" bs of
+  Left err -> Left $ renderError err
+  Right r -> Right r
+  where
+    bottomParser :: Parser Text
+    bottomParser = decodeUtf8 . BS.pack <$> (fmap . fmap) toEnum (groupParser `manyTill` eof)
+
+    groupParser :: Parser Int
+    groupParser = parseNull <|> parseValues
+      where
+        parseNull = zeroParser >> separatorParser >> return 0
+        parseValues = sum <$> (twoHundredParser <|> fiftyParser <|> tenParser <|> fiveParser <|> oneParser) `someTill` separatorParser
+
+    twoHundredParser :: Parser Int
+    twoHundredParser = chunk twoHundred >> return 200
+
+    fiftyParser :: Parser Int
+    fiftyParser = chunk fifty >> return 50
+
+    tenParser :: Parser Int
+    tenParser = chunk ten >> return 10
+
+    fiveParser :: Parser Int
+    fiveParser = chunk five >> return 5
+
+    oneParser :: Parser Int
+    oneParser = chunk one >> return 1
+
+    zeroParser :: Parser Int
+    zeroParser = chunk zero >> return 0
+
+    separatorParser :: Parser ()
+    separatorParser = void $ chunk separator
+
+    -- Custom error messages, because the default error messages print raw
+    -- ByteStrings and don't render correctly.
+    renderError :: ParseErrorBundle ByteString Void -> Text
+    renderError ParseErrorBundle {bundleErrors = (TrivialError offset unexpected expected) :| []} =
+      unexpectedMessage <> expectedMessage <> " at offset " <> T.pack (show offset)
+      where
+        renderErrorItem :: ErrorItem (Token ByteString) -> Text
+        renderErrorItem (Tokens tokens) = "\"" <> decodeUtf8 (BS.pack $ NE.toList tokens) <> "\""
+        renderErrorItem (Label name) = T.pack $ NE.toList name
+        renderErrorItem EndOfInput = "end of input"
+
+        unexpectedMessage = case unexpected of
+          Just unx -> "unexpected " <> renderErrorItem unx <> ": "
+          Nothing -> ""
+
+        expectedMessage = "expected " <> (if length expecteds >= 2 then "one of " else "") <> T.intercalate ", " expecteds
+          where
+            expecteds = renderErrorItem <$> F.toList expected
+    renderError err = T.pack $ errorBundlePretty err
+
+-- Encoding functions.
+
+-- | 'encode' takes a 'Text', and encodes it into a 'Bottom'. To get at the
+-- underlying 'ByteString', unwrap the returned value with 'unBottom'.
+encode :: Text -> Bottom
+encode = Bottom . BS.concatMap encodeByte . encodeUtf8
+
+encodeByte :: Word8 -> ByteString
+encodeByte b
+  | b == zeroBits = zero <> separator
+  | otherwise = BS.concat (unfoldr encodeByte' (fromEnum b)) <> separator
+  where
+    encodeByte' :: Int -> Maybe (ByteString, Int)
+    encodeByte' n
+      | n >= 200 = Just (twoHundred, n - 200)
+      | n >= 50 = Just (fifty, n - 50)
+      | n >= 10 = Just (ten, n - 10)
+      | n >= 5 = Just (five, n - 5)
+      | n >= 1 = Just (one, n - 1)
+      | n == 0 = Nothing
+      | otherwise = error "Data.Encoding.Bottom.encodeByte': impossible: unsigned byte is negative"
diff --git a/test/Main.hs b/test/Main.hs
new file mode 100644
--- /dev/null
+++ b/test/Main.hs
@@ -0,0 +1,48 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module Main (main) where
+
+import Data.Encoding.Bottom (decode, decode', encode, unBottom)
+import Data.Text (Text)
+import qualified Data.Text as T
+import Data.Text.Encoding (encodeUtf8)
+import Test.Hspec (Expectation, describe, hspec, it, shouldBe)
+import Test.Hspec.QuickCheck (prop)
+
+-- TODO: Why does using this character literally cause a GHC lexing error?
+-- Related to https://gitlab.haskell.org/ghc/ghc/-/issues/5518 ?
+twoHundred :: Text
+twoHundred = T.singleton '\129730'
+
+testEncode :: Text -> Text -> Expectation
+testEncode input expected = unBottom (encode input) `shouldBe` encodeUtf8 expected
+
+testDecode :: Text -> Text -> Expectation
+testDecode input expected = case decode' $ encodeUtf8 input of
+  Right r -> encodeUtf8 r `shouldBe` encodeUtf8 expected
+  Left err -> error $ T.unpack err
+
+testCases :: [(Text, Text)]
+testCases =
+  [ ("Test", "💖✨✨✨,,,,👉👈💖💖,👉👈💖💖✨🥺👉👈💖💖✨🥺,👉👈"),
+    ("h", "💖💖,,,,👉👈"),
+    ("🥺", twoHundred <> "✨✨✨✨👉👈💖💖💖🥺,,,,👉👈💖💖💖✨🥺👉👈💖💖💖✨✨✨🥺,👉👈"),
+    ( "がんばれ",
+      twoHundred
+        <> "✨✨🥺,,👉👈💖💖✨✨🥺,,,,👉👈💖💖✨✨✨✨👉👈"
+        <> twoHundred
+        <> "✨✨🥺,,👉👈💖💖✨✨✨👉👈💖💖✨✨✨✨🥺,,👉👈"
+        <> twoHundred
+        <> "✨✨🥺,,👉👈💖💖✨✨🥺,,,,👉👈💖💖💖✨✨🥺,👉👈"
+        <> twoHundred
+        <> "✨✨🥺,,👉👈💖💖✨✨✨👉👈💖💖✨✨✨✨👉👈"
+    )
+  ]
+
+main :: IO ()
+main = hspec $ do
+  -- Taken from https://github.com/bottom-software-foundation/bottom-rs/blob/need_top/src/bottom.rs
+  describe "Data.Encoding.Bottom" $ do
+    it "encodes strings" $ sequence_ $ uncurry testEncode <$> testCases
+    it "decodes strings" $ sequence_ $ uncurry (flip testDecode) <$> testCases
+    prop "decode is the inverse of encode" $ \s -> (T.unpack . decode . encode . T.pack) s `shouldBe` s