diff --git a/CHANGELOG.md b/CHANGELOG.md
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--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,5 @@
+# Changelog for hipsql-api
+
+## 0.0.0.0
+
+* Initial release
diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright SimSpace (c) 2020
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of SimSpace nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Setup.hs b/Setup.hs
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--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/hipsql-api.cabal b/hipsql-api.cabal
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--- /dev/null
+++ b/hipsql-api.cabal
@@ -0,0 +1,41 @@
+cabal-version: 1.12
+
+-- This file has been generated from package.yaml by hpack version 0.31.2.
+--
+-- see: https://github.com/sol/hpack
+--
+-- hash: f1b5fc556493646dc34671dfd75d40b86715250587e57f49023aacd7b113eea6
+
+name:           hipsql-api
+version:        0.0.0.0
+description:    Please see the README on GitHub at <https://github.com/simspace/hipsql#readme>
+homepage:       https://github.com/simspace/hipsql#readme
+bug-reports:    https://github.com/simspace/hipsql/issues
+author:         Cary Robbins
+maintainer:     carymrobbins@gmail.com
+copyright:      2021 SimSpace
+license:        BSD3
+license-file:   LICENSE
+build-type:     Simple
+extra-source-files:
+    CHANGELOG.md
+
+source-repository head
+  type: git
+  location: https://github.com/simspace/hipsql
+
+library
+  exposed-modules:
+      Hipsql.API
+      Hipsql.API.Internal
+  other-modules:
+      Paths_hipsql_api
+  hs-source-dirs:
+      library
+  ghc-options: -Wall
+  build-depends:
+      aeson >=1.4.7.1 && <1.5
+    , base >=4.7 && <5
+    , bytestring >=0.10.10.0 && <0.11
+    , servant >=0.16 && <0.17
+  default-language: Haskell2010
diff --git a/library/Hipsql/API.hs b/library/Hipsql/API.hs
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--- /dev/null
+++ b/library/Hipsql/API.hs
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+-- | Public API for @hipsql@ server and client implementations using @servant@.
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE DerivingStrategies #-}
+{-# LANGUAGE TypeOperators #-}
+module Hipsql.API where
+
+import Data.Proxy (Proxy(Proxy))
+import GHC.Generics (Generic)
+import Hipsql.API.Internal (Version(Version), mkVersion)
+import Servant.API (type (:>), Get, JSON, OctetStream, Post, ReqBody, Summary)
+import Servant.API.Generic (type (:-), ToServantApi)
+import qualified Data.ByteString.Lazy as Lazy
+import qualified Data.List as List
+import qualified Paths_hipsql_api
+
+-- | The servant API type for @hipsql@.
+type HipsqlAPI = ToServantApi HipsqlRoutes
+
+-- | The API routes for @hipsql@.
+data HipsqlRoutes route = HipsqlRoutes
+  { getVersion :: route :-
+      Summary "Gets the current server version"
+        :> "version"
+        :> Get '[JSON] Version
+
+  , eval :: route :-
+      Summary "Evaluate a psql expression"
+        :> "eval"
+        :> ReqBody '[OctetStream] Lazy.ByteString
+        :> Post '[OctetStream] Lazy.ByteString
+  } deriving stock (Generic)
+
+-- | A @hipsql@ API proxy value.
+theHipsqlAPI :: Proxy HipsqlAPI
+theHipsqlAPI = Proxy
+
+-- | The current @hipsql-api@ version; servers and clients should use this
+-- to report which version of the API they are compiled against.
+theHipsqlApiVersion :: Version
+theHipsqlApiVersion = mkVersion Paths_hipsql_api.version
+
+-- | Render a 'Version' to a human-readable 'String'.
+renderVersion :: Version -> String
+renderVersion (Version xs) = List.intercalate "." $ map show xs
+
+-- | Check if two 'Version's are compatible wth one another.
+isCompatibleWith :: Version -> Version -> Bool
+isCompatibleWith (Version xs) (Version ys) =
+  take 2 xs == take 2 ys
diff --git a/library/Hipsql/API/Internal.hs b/library/Hipsql/API/Internal.hs
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--- /dev/null
+++ b/library/Hipsql/API/Internal.hs
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+-- | Internal module which implements the @hipsql@ HTTP API using @servant@.
+{-# LANGUAGE BlockArguments #-}
+{-# LANGUAGE DeriveAnyClass #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE DerivingStrategies #-}
+{-# LANGUAGE LambdaCase #-}
+module Hipsql.API.Internal
+  ( -- * Disclaimer
+    -- $disclaimer
+
+    -- ** Internals
+    module Hipsql.API.Internal
+  ) where
+
+import Data.Aeson (FromJSON, ToJSON)
+import GHC.Generics (Generic)
+import System.Environment (lookupEnv)
+import Text.Read (readMaybe)
+import qualified Data.Version
+
+-- | Lookup the HTTP port to use for a hipsql HTTP server or client
+-- by checking the @HIPSQL_PORT@ environment variable. Defaults
+-- to 'defaultHipsqlPort' if unset.
+lookupHipsqlPort :: IO (Either String Int)
+lookupHipsqlPort =
+  lookupEnvInt "HIPSQL_PORT" `withDefault` Right defaultHipsqlPort
+
+-- | By default, hipsql should use the port @55805@.
+defaultHipsqlPort :: Int
+defaultHipsqlPort = 55805
+
+-- | Lookup an environment variable and parse it as an 'Int'.
+lookupEnvInt :: String -> IO (Maybe (Either String Int))
+lookupEnvInt k =
+  flip fmap (lookupEnv k) \mv ->
+    flip fmap mv \v ->
+      case readMaybe v of
+        Just i -> Right i
+        Nothing -> Left $ "Invalid int for " <> k <> ": " <> v
+
+-- | Used in conjunction with 'lookupEnvInt' to set a default value.
+withDefault :: IO (Maybe a) -> a -> IO a
+withDefault action defaultValue = flip fmap action \case
+  Nothing -> defaultValue
+  Just a -> a
+
+-- | Used to show version information for a hipsql server or client.
+newtype Version = Version
+  { version :: [Int]
+  } deriving stock (Eq, Generic)
+    deriving anyclass (FromJSON, ToJSON)
+
+-- | Constructs a 'Version' from a @Paths_hipsql_*.version@ value.
+mkVersion :: Data.Version.Version -> Version
+mkVersion = Version . Data.Version.versionBranch
+
+-- $disclaimer
+--
+-- Changes to this module will not be reflected in the library's version
+-- updates.