diff --git a/ChangeLog.md b/ChangeLog.md
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--- /dev/null
+++ b/ChangeLog.md
@@ -0,0 +1,3 @@
+# Changelog for gemcap
+
+## Unreleased changes
diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,661 @@
+                    GNU AFFERO GENERAL PUBLIC LICENSE
+                       Version 3, 19 November 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
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+
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+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If your software can interact with users remotely through a computer
+network, you should also make sure that it provides a way for users to
+get its source.  For example, if your program is a web application, its
+interface could display a "Source" link that leads users to an archive
+of the code.  There are many ways you could offer source, and different
+solutions will be better for different programs; see section 13 for the
+specific requirements.
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU AGPL, see
+<https://www.gnu.org/licenses/>.
diff --git a/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,30 @@
+# gemcap
+
+Cooyright (C) Jonathan Lamothe <jonathan@jlamothe.net>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public
+License along with this program.  If not, see
+<https://www.gnu.org/licenses/>.
+
+## Important Note
+
+This project is not yet ready for release. Everything within it should
+be considered unstable and subject to change at any time.
+
+## Executive Summary
+
+This library is inspired very heavily by the
+[gemini-server](https://hackage.haskell.org/package/gemini-server)
+package, but does not need to be linked against OpenSSL. Instead, it
+uses [tcp-streams](https://hackage.haskell.org/package/tcp-streams) to
+provide TLS functionality.
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/gemcap.cabal b/gemcap.cabal
new file mode 100644
--- /dev/null
+++ b/gemcap.cabal
@@ -0,0 +1,72 @@
+cabal-version: 2.2
+
+-- This file has been generated from package.yaml by hpack version 0.34.4.
+--
+-- see: https://github.com/sol/hpack
+
+name:           gemcap
+version:        0.1.0
+synopsis:       a simple Gemini capsule (server)
+description:    a simple Gemini capsule (server) - see README.md for details
+category:       Gemini
+homepage:       https://codeberg.org/jlamothe/gemcap
+bug-reports:    https://codeberg.org/jlamothe/gemcap/issues
+author:         Jonathan Lamothe
+maintainer:     jonathan@jlamothe.net
+copyright:      2021 Jonathan Lamothe
+license:        AGPL-3.0-or-later
+license-file:   LICENSE
+build-type:     Simple
+extra-source-files:
+    README.md
+    ChangeLog.md
+
+library
+  exposed-modules:
+      Network.Gemini.Capsule
+      Network.Gemini.Capsule.Encoding
+      Network.Gemini.Capsule.Internal
+      Network.Gemini.Capsule.Types
+  other-modules:
+      Paths_gemcap
+  hs-source-dirs:
+      src
+  ghc-options: -Wall
+  build-depends:
+      base >=4.7 && <5
+    , bytestring >=0.10.12.0 && <0.11
+    , io-streams
+    , network
+    , tcp-streams >=1.0.1.1 && <1.1
+    , text >=1.2.4.1 && <1.3
+    , tls
+    , transformers
+    , x509
+  default-language: Haskell2010
+  autogen-modules: Paths_gemcap
+
+test-suite gemcap-test
+  type: exitcode-stdio-1.0
+  main-is: Spec.hs
+  other-modules:
+      Network.Gemini.Capsule.EncodingSpec
+      Network.Gemini.Capsule.InternalSpec
+      Network.Gemini.CapsuleSpec
+      Paths_gemcap
+  hs-source-dirs:
+      test
+  ghc-options: -Wall -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      base >=4.7 && <5
+    , bytestring >=0.10.12.0 && <0.11
+    , gemcap
+    , hspec >=2.7.10 && <2.8
+    , io-streams
+    , network
+    , tcp-streams >=1.0.1.1 && <1.1
+    , text >=1.2.4.1 && <1.3
+    , tls
+    , transformers
+    , x509
+  default-language: Haskell2010
+  autogen-modules: Paths_gemcap
diff --git a/src/Network/Gemini/Capsule.hs b/src/Network/Gemini/Capsule.hs
new file mode 100644
--- /dev/null
+++ b/src/Network/Gemini/Capsule.hs
@@ -0,0 +1,100 @@
+{-|
+
+Module      : Network.Gemini.Capsule
+Description : Gemini capsule stuff
+Copyright   : (C) Jonathan Lamothe
+License     : AGPL-3.0-or-later
+Maintainer  : jonathan@jlamothe.net
+Stability   : experimental
+Portability : POSIX
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public
+License along with this program.  If not, see
+<https://www.gnu.org/licenses/>.
+
+-}
+
+{-# LANGUAGE LambdaCase, ScopedTypeVariables #-}
+
+module Network.Gemini.Capsule (
+  runGemCapsule
+) where
+
+import Control.Concurrent (forkIO)
+import Control.Exception (IOException, try)
+import Control.Exception.Base (bracket, finally)
+import Control.Monad (void)
+import qualified Data.Connection as C
+import Data.IORef (IORef, newIORef, readIORef, writeIORef)
+import Data.TLSSetting (makeServerParams)
+import Data.X509 (Certificate, CertificateChain (..), getSigned, signedObject)
+import qualified Network.Socket as S
+import Network.TLS (ServerParams, onClientCertificate, serverHooks)
+import System.IO.Streams.TCP (bindAndListen)
+import System.IO.Streams.TLS (accept)
+
+import Network.Gemini.Capsule.Internal
+import Network.Gemini.Capsule.Types
+
+-- | Builds and runs a Gemini capsule
+runGemCapsule
+  :: GemCapSettings
+  -- ^ The capsule settings
+  -> GemHandler
+  -- ^ The handler
+  -> IO a
+runGemCapsule settings handler = bracket
+  ( bindAndListen
+    (capConnections settings)
+    (fromIntegral $ capPort settings)
+  )
+  S.close
+  ( \sock -> do
+    params <- makeServerParams
+      (capCert settings)
+      (capCertChain settings)
+      (capKey settings)
+    listenLoop sock params handler
+  )
+
+listenLoop :: S.Socket -> ServerParams -> GemHandler -> IO a
+listenLoop sock params handler = do
+  certRef <- newIORef Nothing
+  let params' = adjustServerParams certRef params
+  try (accept params' sock) >>= \case
+    Left (_::IOException) -> return ()
+    Right conn            -> void $ forkIO $ finally
+      (readIORef certRef >>= runConnection conn handler)
+      (C.close conn)
+  listenLoop sock params handler
+
+adjustServerParams
+  :: IORef (Maybe Certificate)
+  -> ServerParams
+  -> ServerParams
+adjustServerParams certRef params = let
+  hooks    = serverHooks params
+  certHook = onClientCertificate hooks
+
+  certHook' chain = do
+    case chain of
+      CertificateChain []     -> return ()
+      CertificateChain (se:_) -> do
+        let cert = signedObject $ getSigned se
+        writeIORef certRef (Just cert)
+    certHook chain
+
+  hooks' = hooks { onClientCertificate = certHook' }
+  in params { serverHooks = hooks' }
+
+--jl
diff --git a/src/Network/Gemini/Capsule/Encoding.hs b/src/Network/Gemini/Capsule/Encoding.hs
new file mode 100644
--- /dev/null
+++ b/src/Network/Gemini/Capsule/Encoding.hs
@@ -0,0 +1,168 @@
+{-|
+
+Module      : Network.Gemini.Capsule.Encoding
+Description : funcitons to encode/decode our data types
+Copyright   : (C) Jonathan Lamothe
+License     : AGPL-3.0-or-later
+Maintainer  : jonathan@jlamothe.net
+Stability   : experimental
+Portability : POSIX
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public
+License along with this program.  If not, see
+<https://www.gnu.org/licenses/>.
+
+-}
+
+{-# LANGUAGE LambdaCase, OverloadedStrings, RecordWildCards #-}
+
+module Network.Gemini.Capsule.Encoding (
+  encodeGemURL,
+  decodeGemURL,
+  escapeString,
+  unescapeString,
+  encodeGemResponse
+) where
+
+import qualified Data.ByteString as BS
+import Data.ByteString.Builder (
+  charUtf8,
+  lazyByteString,
+  stringUtf8,
+  toLazyByteString,
+  word8Dec)
+import qualified Data.ByteString.Lazy as BSL
+import Data.Char (chr, ord, toLower)
+import Data.List (find, intercalate)
+import Data.Maybe (fromJust, fromMaybe)
+import qualified Data.Text as T
+import Data.Text.Encoding (decodeUtf8')
+
+import Network.Gemini.Capsule.Types
+
+-- | Encodes a 'GemURL' into a 'String'
+encodeGemURL :: GemURL -> String
+encodeGemURL url =
+  "gemini://" ++ authority ++ "/" ++ path ++ query
+  where
+    authority = gemHost url ++ case gemPort url of
+      Just port -> ':' : show port
+      Nothing   -> ""
+    path = intercalate "/" $ map escapeString $ gemPath url
+    query = case gemQuery url of
+      Nothing -> ""
+      Just q  -> '?' : escapeString q
+
+-- | Decodes a 'GemURL' from a 'String' (if possible)
+decodeGemURL :: String -> Maybe GemURL
+decodeGemURL str = do
+  let txt = T.pack str
+
+  noProt <- case T.splitOn "://" txt of
+    [prot, rest] -> if T.toLower prot == "gemini"
+      then Just rest
+      else Nothing
+    _ -> Nothing
+
+  noFrag <- case T.splitOn "#" noProt of
+    [x, _] -> Just x
+    [x]    -> Just x
+    _      -> Nothing
+
+  (noQuery, query) <- case T.splitOn "?" noFrag of
+    [nq, q] -> Just (nq, Just q)
+    [nq]    -> Just (nq, Nothing)
+    _       -> Nothing
+
+  gemQuery <- case query of
+    Just q  -> Just <$> unescapeString (T.unpack q)
+    Nothing -> Just Nothing
+
+  (auth, path) <- case T.splitOn "/" noQuery of
+    [a]     -> Just (a, [])
+    [a, ""] -> Just (a, [])
+    a:ps    -> Just (a, ps)
+    _       -> Nothing
+
+  gemPath  <- mapM (unescapeString . T.unpack) path
+
+  (host, gemPort) <- case T.splitOn ":" auth of
+    [h, p] -> case reads $ T.unpack p of
+      [(n, "")] -> Just (h, Just n)
+      _         -> Nothing
+    [h] -> Just (h, Nothing)
+    _   -> Nothing
+
+  let gemHost = T.unpack host
+  Just GemURL {..}
+
+-- | add required escape sequences to a string
+escapeString :: String -> String
+escapeString = concatMap
+  ( \n -> let ch = chr $ fromIntegral n in
+    if ch `elem` unescaped
+    then [ch]
+    else '%' : toHex n
+  ) . BSL.unpack . toLazyByteString . stringUtf8
+  where
+    unescaped = ['0'..'9'] ++ ['A'..'Z'] ++ ['a'..'z'] ++ "~-_."
+    toHex =
+      ( \n -> let
+        high = n `div` 16
+        low  = n `mod` 16
+        in [hexDigits !! high, hexDigits !! low]
+      ) . fromIntegral
+
+-- | decode an escaped string back to its original value
+unescapeString :: String -> Maybe String
+unescapeString str = case decodeUtf8' $ BS.pack $ toBytes str of
+    Right t -> Just $ T.unpack t
+    _       -> Nothing
+  where
+    toBytes = \case
+      "" -> []
+      '%':h:l:sub -> let
+        h' = toLower h
+        l' = toLower l
+        in if h' `elem` hexDigits && l' `elem` hexDigits
+        then toByte h' l' : toBytes sub
+        else fromIntegral (ord '%') : toBytes (h : l : sub)
+      ch:sub ->
+        BSL.unpack (toLazyByteString $ charUtf8 ch) ++ toBytes sub
+    toByte h l = toNum h * 16 + toNum l
+    toNum ch = fst $ fromJust $
+      find (\x -> snd x == ch) $ zip [0..] hexDigits
+
+-- | encodes a 'GemResponse' into a lazy ByteString
+encodeGemResponse :: GemResponse -> BSL.ByteString
+encodeGemResponse resp = let
+  code = respStatus resp
+  high = code `div` 10
+  low  = code `mod` 10
+  meta = respMeta resp
+  body = fromMaybe "" $ respBody resp
+
+  builder
+    =  word8Dec high
+    <> word8Dec low
+    <> charUtf8 ' '
+    <> stringUtf8 meta
+    <> stringUtf8 "\r\n"
+    <> lazyByteString body
+
+  in toLazyByteString builder
+
+hexDigits :: String
+hexDigits = ['0'..'9'] ++ ['a'..'f']
+
+--jl
diff --git a/src/Network/Gemini/Capsule/Internal.hs b/src/Network/Gemini/Capsule/Internal.hs
new file mode 100644
--- /dev/null
+++ b/src/Network/Gemini/Capsule/Internal.hs
@@ -0,0 +1,151 @@
+{-|
+
+Module      : Network.Gemini.Capsule.Internal
+Description : internal functions (do not use)
+Copyright   : (C) Jonathan Lamothe
+License     : AGPL-3.0-or-later
+Maintainer  : jonathan@jlamothe.net
+Stability   : experimental
+Portability : POSIX
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public
+License along with this program.  If not, see
+<https://www.gnu.org/licenses/>.
+
+= Important Note
+
+This is an internal module.  It is not intended to be accessed by
+outside packages, and should be considered subject to change at any
+time.
+
+-}
+
+{-# LANGUAGE LambdaCase #-}
+
+module Network.Gemini.Capsule.Internal (
+  runConnection,
+  readURL,
+  strFromConn,
+  readMax,
+  stripCRLF
+) where
+
+import Control.Monad (when)
+import Control.Monad.Trans.Class (lift)
+import Control.Monad.Trans.Maybe (MaybeT (..))
+import qualified Data.ByteString as BS
+import Data.ByteString.Builder (Builder, byteString, toLazyByteString)
+import qualified Data.ByteString.Lazy as BSL
+import Data.Connection (Connection, send, source)
+import qualified Data.Text as T
+import Data.Text.Encoding (decodeUtf8')
+import Data.X509 (Certificate)
+import qualified System.IO.Streams as S
+
+import Network.Gemini.Capsule.Encoding
+import Network.Gemini.Capsule.Types
+
+-- Constants
+
+-- Maximum size to read from a conneciton
+inBufSize :: Int
+inBufSize = 1026
+
+-- | process a request and return a response over a 'Connection'
+runConnection
+  :: Connection a
+  -> GemHandler
+  -> Maybe Certificate
+  -> IO ()
+runConnection conn handler mCert =
+  ( readURL conn >>= \case
+    Nothing -> return $ newGemResponse
+      { respStatus = 59
+      , respMeta   = "bad request"
+      }
+    Just url -> handler (newGemRequest url) { reqCert = mCert }
+  ) >>= sendResponse conn
+
+-- | Reads a 'GemURL' from a 'Connection'
+readURL
+  :: Connection a
+  -- ^ the connection
+  -> IO (Maybe GemURL)
+readURL conn =
+  strFromConn inBufSize conn >>= return <$> \case
+    Nothing  -> Nothing
+    Just str -> decodeGemURL str
+
+-- | Reads up to a maxumum number of bytes from a 'Connection', UTF-8
+-- decodes it, and returns the resulting string (if possible) without
+-- the trailing CR/LF
+strFromConn
+  :: Int
+  -- ^ The maximum number of bytes to read
+  -> Connection a
+  -- ^ The connection to read from
+  -> IO (Maybe String)
+strFromConn maxLen conn = do
+  mbs <- readMax maxLen conn
+  return $ do
+    bs  <- mbs
+    txt <- case decodeUtf8' bs of
+      Left _  -> Nothing
+      Right s -> Just s
+    stripCRLF $ T.unpack txt
+
+-- | Reads from a connection up to a maximum number of bytes or a
+-- newline character is encountered, returning 'Nothing' if the limit
+-- is exceeded
+readMax
+  :: Int
+  -- ^ the maximum number of bytes
+  -> Connection a
+  -- ^ the 'Connection' to read from
+  -> IO (Maybe BS.ByteString)
+readMax maxLen conn = do
+  let src = source conn
+  runMaybeT $
+    BS.pack . BSL.unpack . toLazyByteString
+    <$> readLoop maxLen src
+
+-- | Strips the CR/LF characters from the end of a string, retuning
+-- Nothing if they are not present
+stripCRLF :: String -> Maybe String
+stripCRLF = \case
+  ""     -> Nothing
+  "\r\n" -> Just ""
+  c:str  -> (c:) <$> stripCRLF str
+
+readLoop :: Int -> S.InputStream BS.ByteString -> MaybeT IO Builder
+readLoop maxLen src = lift (S.read src) >>= \case
+  Nothing -> return mempty
+  Just bs -> do
+    let
+      len = BS.length bs
+      b   = byteString bs
+    when (len > maxLen) $
+      fail "maximum length exceeded"
+    if BS.any (== 0xa) bs
+      then return b
+      else (b <>) <$> readLoop (maxLen - len) src
+
+sendResponse
+  :: Connection a
+  -- ^ the connection
+  -> GemResponse
+  -- ^ the response being sent
+  -> IO ()
+sendResponse conn resp = send conn $ encodeGemResponse resp
+
+--jl
diff --git a/src/Network/Gemini/Capsule/Types.hs b/src/Network/Gemini/Capsule/Types.hs
new file mode 100644
--- /dev/null
+++ b/src/Network/Gemini/Capsule/Types.hs
@@ -0,0 +1,137 @@
+{-|
+
+Module      : Network.Gemini.Capsule.Types
+Description : Gemini capsule types
+Copyright   : (C) Jonathan Lamothe
+License     : AGPL-3.0-or-later
+Maintainer  : jonathan@jlamothe.net
+Stability   : experimental
+Portability : POSIX
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public
+License along with this program.  If not, see
+<https://www.gnu.org/licenses/>.
+
+-}
+
+module Network.Gemini.Capsule.Types (
+  -- * Types
+  GemURL (..),
+  GemRequest (..),
+  GemResponse (..),
+  GemHandler,
+  GemCapSettings (..),
+  -- * Constructors
+  newGemURL,
+  newGemRequest,
+  newGemResponse,
+  newGemCapSettings
+) where
+
+import qualified Data.ByteString.Lazy as BSL
+import Data.Word (Word8, Word16, Word32)
+import Data.X509 (Certificate)
+
+-- | Gemini URL
+data GemURL = GemURL
+  { gemHost :: String
+  -- ^ The host part of the authority section, e.g.: "example.com"
+  , gemPort :: Maybe Word32
+  -- ^ The port number (if supplied)
+  , gemPath :: [String]
+  -- ^ The decoded path segments
+  , gemQuery :: Maybe String
+  -- ^ The decoded request query (if supplied)
+  } deriving (Eq, Show)
+
+-- | Describes a Gemini request
+data GemRequest = GemRequest
+  { reqURL :: GemURL
+  -- ^ The URL being requested
+  , reqCert :: Maybe Certificate
+  -- ^ The client certificate (if available)
+  } deriving (Eq, Show)
+
+-- | Describes a response to a Gemini request
+data GemResponse = GemResponse
+  { respStatus :: Word8
+  -- ^ The response status code
+  , respMeta :: String
+  -- ^ The response metadata
+  , respBody :: Maybe BSL.ByteString
+  -- ^ The response body
+  } deriving (Eq, Show)
+
+-- | Handles a 'GemRequest' to produce a 'GemResponse'
+type GemHandler = GemRequest -> IO GemResponse
+
+-- | The settings required to set up a Gemini capsule
+data GemCapSettings = GemCapSettings
+  { capConnections :: Int
+  -- ^ Number of simultaneous connections allowed
+  , capPort :: Word16
+  -- ^ The capsule port number
+  , capCert :: FilePath
+  -- ^ The path to the TLS certificate
+  , capCertChain :: [FilePath]
+  -- ^ The paths to the chain certificates
+  , capKey :: FilePath
+  -- ^ The path to the private key
+  } deriving (Eq, Show)
+
+-- | Builds a new 'GemURL'
+newGemURL
+  :: String
+  -- ^ The hostname
+  -> GemURL
+newGemURL host = GemURL
+  { gemHost  = host
+  , gemPort  = Nothing
+  , gemPath  = []
+  , gemQuery = Nothing
+  }
+
+-- | Builds a 'GemRequest'
+newGemRequest
+  :: GemURL
+  -- ^ The request URL
+  -> GemRequest
+newGemRequest url = GemRequest
+  { reqURL  = url
+  , reqCert = Nothing
+  }
+
+-- | Builds a 'GemResponse'
+newGemResponse :: GemResponse
+newGemResponse = GemResponse
+  { respStatus = 20
+  , respMeta   = "text/gemini"
+  , respBody   = Nothing
+  }
+
+-- | Builds a reasonable set of server settings.
+newGemCapSettings
+  :: FilePath
+  -- ^ Path to the server certificate
+  -> FilePath
+  -- ^ Path to the private key
+  -> GemCapSettings
+newGemCapSettings cert key = GemCapSettings
+  { capConnections = 100
+  , capPort        = 1965
+  , capCert        = cert
+  , capCertChain   = []
+  , capKey         = key
+  }
+
+--jl
diff --git a/test/Network/Gemini/Capsule/EncodingSpec.hs b/test/Network/Gemini/Capsule/EncodingSpec.hs
new file mode 100644
--- /dev/null
+++ b/test/Network/Gemini/Capsule/EncodingSpec.hs
@@ -0,0 +1,157 @@
+{-
+
+gemcap
+
+Cooyright (C) Jonathan Lamothe <jonathan@jlamothe.net>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public
+License along with this program.  If not, see
+<https://www.gnu.org/licenses/>.
+
+-}
+
+{-# LANGUAGE OverloadedStrings #-}
+
+module Network.Gemini.Capsule.EncodingSpec (spec) where
+
+import Test.Hspec (Spec, context, describe, it, shouldBe)
+
+import Network.Gemini.Capsule.Encoding
+import Network.Gemini.Capsule.Types
+
+spec :: Spec
+spec = describe "Encoding" $ do
+  encodeGemURLSpec
+  decodeGemURLSpec
+  escapeStringSpec
+  unescapeStringSpec
+  encodeGemResponseSpec
+
+encodeGemURLSpec :: Spec
+encodeGemURLSpec = describe "encodeGemURL" $ mapM_
+  ( \(desc, req, expected) -> context desc $
+    it ("should be " ++ show expected) $
+      encodeGemURL req `shouldBe` expected
+  )
+
+  --  description,   request,       expected
+  [ ( "simple",      simpleURL,     simpleExp     )
+  , ( "with port",   withPortURL,   withPortExp   )
+  , ( "with path",   withPathURL,   withPathExp   )
+  , ( "with query",  withQueryURL,  withQueryExp  )
+  , ( "blank query", blankQueryURL, blankQueryExp )
+  , ( "with escape", withEscapeURL, withEscapeExp )
+  ]
+
+  where
+    simpleURL     = newGemURL "example.com"
+    simpleExp     = "gemini://example.com/"
+    withPortURL   = simpleURL { gemPort = Just 1965 }
+    withPortExp   = "gemini://example.com:1965/"
+    withPathURL   = simpleURL { gemPath = ["foo", "bar"] }
+    withPathExp   = "gemini://example.com/foo/bar"
+    withQueryURL  = simpleURL { gemQuery = Just "foo" }
+    withQueryExp  = "gemini://example.com/?foo"
+    blankQueryURL = simpleURL { gemQuery = Just "" }
+    blankQueryExp = "gemini://example.com/?"
+
+    withEscapeURL = simpleURL
+      { gemPath  = ["foo bar"]
+      , gemQuery = Just "baz quux"
+      }
+
+    withEscapeExp = "gemini://example.com/foo%20bar?baz%20quux"
+
+decodeGemURLSpec :: Spec
+decodeGemURLSpec = describe "decodeGemURL" $ mapM_
+  ( \(str, expected) -> context (show str) $
+    it ("should be " ++ show expected) $
+      decodeGemURL str `shouldBe` expected
+  )
+
+  --  URL string,   expected
+  [ ( simpleStr,       Just simpleURL     )
+  , ( withSlashStr,    Just simpleURL     )
+  , ( withPathStr,     Just withPathURL   )
+  , ( withQueryStr,    Just withQueryURL  )
+  , ( pathQueryStr,    Just pathQueryURL  )
+  , ( blankQueryStr,   Just blankQueryURL )
+  , ( withFragmentStr, Just simpleURL     )
+  , ( escapedStr,      Just escapedURL    )
+  , ( httpStr,         Nothing            )
+  , ( malformed,       Nothing            )
+  , ( "",              Nothing            )
+  ]
+
+  where
+    simpleStr       = "gemini://example.com"
+    simpleURL       = newGemURL "example.com"
+    withSlashStr    = simpleStr ++ "/"
+    withPathStr     = simpleStr ++ "/foo/bar"
+    withPathURL     = simpleURL { gemPath = ["foo", "bar"] }
+    withQueryStr    = simpleStr ++ "?foo"
+    withQueryURL    = simpleURL { gemQuery = Just "foo" }
+    pathQueryStr    = withPathStr ++ "?baz"
+    pathQueryURL    = withPathURL { gemQuery = Just "baz" }
+    blankQueryStr   = simpleStr ++"?"
+    blankQueryURL   = simpleURL { gemQuery = Just "" }
+    withFragmentStr = simpleStr ++ "#foo"
+    escapedStr      = simpleStr ++ "/foo%20bar/baz?quux%20stuff"
+
+    escapedURL      = simpleURL
+      { gemPath = ["foo bar", "baz"]
+      , gemQuery = Just "quux stuff"
+      }
+
+    httpStr   = "http://example.com"
+    malformed = "foo"
+
+escapeStringSpec :: Spec
+escapeStringSpec = describe "escapeString" $ mapM_
+  ( \(input, expected) -> context (show input) $
+    it ("should be " ++ show expected) $
+      escapeString input `shouldBe` expected
+  )
+
+  --  input,               expected
+  [ ( "~foo-bar_baz.quux", "~foo-bar_baz.quux"        )
+  , ( "foo:/?=&#%",        "foo%3a%2f%3f%3d%26%23%25" )
+  , ( "foo\xe9",           "foo%c3%a9"                )
+  ]
+
+unescapeStringSpec :: Spec
+unescapeStringSpec = describe "unescapeString" $ mapM_
+  ( \(input, expected) -> context (show input) $
+    it ("should be " ++ show expected) $
+      unescapeString input `shouldBe` expected
+  )
+
+  --  input,       expected
+  [ ( "foo",       Just "foo"     )
+  , ( "foo%20bar", Just "foo bar" )
+  , ( "foo%7x",    Just "foo%7x"  )
+  , ( "foo%a",     Just "foo%a"   )
+  , ( "foo%",      Just "foo%"    )
+  , ( "foo%c3%a9", Just "foo\xe9" )
+  , ( "foo%ff",    Nothing        )
+  ]
+
+encodeGemResponseSpec :: Spec
+encodeGemResponseSpec = describe "encodeGemResponse" $
+  it ("should be " ++ show expect) $
+    encodeGemResponse resp `shouldBe` expect
+  where
+    resp   = newGemResponse { respBody = Just "Success!\r\n" }
+    expect = "20 text/gemini\r\nSuccess!\r\n"
+
+--jl
diff --git a/test/Network/Gemini/Capsule/InternalSpec.hs b/test/Network/Gemini/Capsule/InternalSpec.hs
new file mode 100644
--- /dev/null
+++ b/test/Network/Gemini/Capsule/InternalSpec.hs
@@ -0,0 +1,202 @@
+{-
+
+gemcap
+
+Cooyright (C) Jonathan Lamothe <jonathan@jlamothe.net>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public
+License along with this program.  If not, see
+<https://www.gnu.org/licenses/>.
+
+-}
+
+{-# LANGUAGE OverloadedStrings, RecordWildCards #-}
+
+module Network.Gemini.Capsule.InternalSpec (spec) where
+
+import qualified Data.ByteString as BS
+import qualified Data.ByteString.Lazy as BSL
+import Data.Char (ord)
+import Data.Connection (Connection (..))
+import Data.IORef (IORef, modifyIORef', newIORef, readIORef)
+import Data.X509 (Certificate (..))
+import System.IO.Streams (nullInput, unRead)
+import Test.Hspec (
+  Spec,
+  context,
+  describe,
+  it,
+  shouldBe,
+  shouldReturn)
+
+import Network.Gemini.Capsule.Types
+import Network.Gemini.Capsule.Internal
+
+spec :: Spec
+spec = describe "Internal" $ do
+  runConnectionSpec
+  readURLSpec
+  strFromConnSpec
+  readMaxSpec
+  stripCRLFSpec
+
+runConnectionSpec :: Spec
+runConnectionSpec = describe "runConnection" $ mapM_
+  ( \(desc, ioConnRef, handler, mCert, expect) -> context desc $
+    it ("should return " ++ show expect) $ do
+      (conn, outRef) <- ioConnRef
+      runConnection conn handler mCert
+      readIORef outRef `shouldReturn` expect
+  )
+
+  --  description,            connection,  handler, certificate,     expectation
+  [ ( "basic connection",     basicConn,   basicH,  Nothing,         basicExp    )
+  , ( "no certificate",       basicConn,   certH,   Nothing,         noCertExp   )
+  , ( "with certificate",     basicConn,   certH,   Just sampleCert, basicExp    )
+  , ( "gibberish with CR/LF", gibConnCRLF, basicH,  Nothing,         gibExp      )
+  , ( "gibberish w/o CR/LF",  gibConn,     basicH,  Nothing,         gibExp      )
+  ]
+
+  where
+    basicConn   = mkIOConn ["gemini://example.com/\r\n"]
+    gibConnCRLF = mkIOConn ["aosidjgfoeribjeworifj\r\n"]
+    gibConn     = mkIOConn ["sodifjboije"]
+    basicH _    = return newGemResponse { respBody = Just success }
+
+    certH req = return $ case reqCert req of
+      Nothing -> newGemResponse
+        { respStatus = 60
+        , respMeta   = "certificate required"
+        }
+      Just _ -> newGemResponse { respBody = Just success }
+
+    basicExp  = ["20 text/gemini\r\nSuccess!\r\n"]
+    noCertExp = ["60 certificate required\r\n"]
+    gibExp    = ["59 bad request\r\n"]
+    success   = "Success!\r\n"
+
+readURLSpec :: Spec
+readURLSpec = describe "readURL" $ mapM_
+  ( \(desc, ioConn, expect) -> context desc $
+    it ("should return " ++ show expect) $
+      do
+        conn <- ioConn
+        readURL conn `shouldReturn` expect
+  )
+
+  --  description,       connection,  expected result
+  [ ( "valid URL",       validConn,   Just validExp   )
+  , ( "long URL",        longConn,    Just longExp    )
+  , ( "too long URL",    tooLongConn, Nothing         )
+  , ( "gibberish input", gibConn,     Nothing         )
+  ]
+
+  where
+    validConn   = mkInConn ["gemini://example.com/\r\n"]
+    longConn    = mkInConn [longBS]
+    tooLongConn = mkInConn [tooLongBS]
+    gibConn     = mkInConn ["aosidjfwoeinboijwefr"]
+    longBS      = BS.pack (take 1024 bytes) <> "\r\n"
+    tooLongBS   = BS.pack (take 1025 bytes) <> "\r\n"
+    bytes       = BS.unpack prefix ++ repeat (fromIntegral $ ord 'A')
+    validExp    = newGemURL "example.com"
+    longExp     = validExp { gemPath = [longDir] }
+    longDir     = replicate (1024 - BS.length prefix) 'A'
+    prefix      = "gemini://example.com/"
+
+strFromConnSpec :: Spec
+strFromConnSpec = describe "strFromConn" $ mapM_
+  ( \(desc, maxLen, ioConn, expect) -> context desc $
+    it ("should return " ++ show expect) $ do
+      conn <- ioConn
+      strFromConn maxLen conn `shouldReturn` expect
+  )
+
+  --  description,    max size, connection,                expected
+  [ ( "valid string", 100,      mkInConn ["foo\r\n"],      Just "foo"  )
+  , ( "long string",  5,        mkInConn ["too long\r\n"], Nothing     )
+  , ( "no CR/LF",     100,      mkInConn ["foo"],          Nothing     )
+  , ( "bad UTF-8",    100,      mkInConn ["foo\xff\r\n"],  Nothing     )
+  , ( "non-ASCII",    100,      mkInConn ["\xc3\xa9\r\n"], Just "\xe9" )
+  ]
+
+readMaxSpec :: Spec
+readMaxSpec = describe "readMax" $ mapM_
+  ( \(desc, maxLen, ioConn, expect) -> context desc $
+    it ("should return " ++ show expect) $ do
+      conn <- ioConn
+      readMax maxLen conn `shouldReturn` expect
+  )
+
+  --  description,    max length,   connection,  expected
+  [ ( "single input", 1024,         singleConn,  Just singleBS )
+  , ( "multi input",  1024,         multiConn,   Just multiBS  )
+  , ( "long input",   longLen,      longConn,    Just longBS   )
+  , ( "too long",     pred longLen, longConn,    Nothing       )
+  , ( "empty input",  1024,         mkInConn [], Just ""       )
+  ]
+
+  where
+    singleConn = mkInConn ["foo"]
+    multiConn  = mkInConn ["foo", "bar", "baz"]
+    longConn   = mkInConn [longBS]
+    longLen    = BS.length longBS
+    singleBS   = "foo"
+    multiBS    = "foobarbaz"
+    longBS     = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+
+stripCRLFSpec :: Spec
+stripCRLFSpec = describe "stripCRLF" $ mapM_
+  ( \(input, expected) -> context (show input) $
+    it ("should be" ++ show expected) $
+      stripCRLF input `shouldBe` expected
+  )
+
+  --  input,     expectation
+  [ ( "foo\r\n", Just "foo"  )
+  , ( "foo\n",   Nothing     )
+  , ( "foo",     Nothing     )
+  , ( "\r\n",    Just ""     )
+  ]
+
+mkIOConn :: [BS.ByteString] -> IO (Connection (), IORef [BSL.ByteString])
+mkIOConn input = do
+  ref  <- newIORef []
+  conn <-
+    ( \c -> c { send = \bs -> modifyIORef' ref (++[bs]) }
+    ) <$> mkInConn input
+  return (conn, ref)
+
+mkInConn :: [BS.ByteString] -> IO (Connection ())
+mkInConn bss = do
+  source <- nullInput
+  mapM_ (`unRead` source) (reverse bss)
+  let
+    send          = const $ return ()
+    close         = return ()
+    connExtraInfo = ()
+  return Connection {..}
+
+sampleCert :: Certificate
+sampleCert = Certificate
+  { certVersion      = undefined
+  , certSerial       = undefined
+  , certSignatureAlg = undefined
+  , certIssuerDN     = undefined
+  , certValidity     = undefined
+  , certSubjectDN    = undefined
+  , certPubKey       = undefined
+  , certExtensions   = undefined
+  }
+
+--jl
diff --git a/test/Network/Gemini/CapsuleSpec.hs b/test/Network/Gemini/CapsuleSpec.hs
new file mode 100644
--- /dev/null
+++ b/test/Network/Gemini/CapsuleSpec.hs
@@ -0,0 +1,35 @@
+{-
+
+gemcap
+
+Cooyright (C) Jonathan Lamothe <jonathan@jlamothe.net>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public
+License along with this program.  If not, see
+<https://www.gnu.org/licenses/>.
+
+-}
+
+module Network.Gemini.CapsuleSpec (spec) where
+
+import Test.Hspec (Spec, describe)
+
+import qualified Network.Gemini.Capsule.EncodingSpec as Encoding
+import qualified Network.Gemini.Capsule.InternalSpec as Internal
+
+spec :: Spec
+spec = describe "Network.Gemini.Capsule" $ do
+  Encoding.spec
+  Internal.spec
+
+--jl
diff --git a/test/Spec.hs b/test/Spec.hs
new file mode 100644
--- /dev/null
+++ b/test/Spec.hs
@@ -0,0 +1,31 @@
+{-
+
+gemcap
+
+Cooyright (C) Jonathan Lamothe <jonathan@jlamothe.net>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public
+License along with this program.  If not, see
+<https://www.gnu.org/licenses/>.
+
+-}
+
+module Main (main) where
+
+import Test.Hspec (hspec)
+import qualified Network.Gemini.CapsuleSpec as GemCap
+
+main :: IO ()
+main = hspec GemCap.spec
+
+--jl