servant-serf: Automatically generate Servant API modules.

[ library, mit, program, web ] [ Propose Tags ]


servant-serf is a preprocessor for GHC that automatically generates Servant API modules. It is similar to the hspec-discover package.

Example input

{-# OPTIONS_GHC -F -pgmF servant-serf #-}

Example output

{-# LINE 1 "Example.hs" #-}
{-# OPTIONS_GHC -w #-}

module Example where

import qualified Servant

import qualified Example.One
import qualified Example.Two

type API
  = Example.One.API
  Servant.:<|> Example.Two.API

  = Example.One.server
  Servant.:<|> Example.Two.server


To pass options into servant-serf, use -optF. For example:

{-# OPTIONS_GHC -F -pgmF servant-serf -optF --depth=shallow #-}
  • --module-name=STRING: Sets the name to use for the generated module. By default this is determined from the source file path. For example src/X.hs would use the module name X.

  • --depth=deep|shallow: Controls whether to search through only one dierctory (shallow) or recursively (deep). Defaults to deep.

  • --api-name=STRING: Sets the name to use for the API type. Defaults to API. Note that the same name is used for both referenced API types and the generated API type.

  • --server-name=STRING: Sets the name to use for the server value. Defaults to server. Note that the same name is used for both referenced server values and the generated server value.


  • The input module is completely ignored.

  • Modules are sorted by name. There is no way to customize how they are sorted.

  • All modules below the current module are included. There is no way to customize which modules are included or excluded.

  • The generated server value does not have a type signature. It should have type Servant.ServerT API m for some m, but that m can change and is easily inferred by GHC.

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Manual Flags


Enables -Werror, which turns warnings into errors.


Use -f <flag> to enable a flag, or -f -<flag> to disable that flag. More info


Maintainer's Corner

For package maintainers and hackage trustees


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Versions [RSS] 0.0.1, 0.0.2, 0.0.3, 0.1.0, 0.1.1, 0.1.2, 0.2.0, 0.2.1,,,, (info)
Change log CHANGELOG.markdown
Dependencies base (>=4.14.0 && <4.17), Cabal (>=3.2.0 && <3.7), directory (>=1.3.6 && <1.4), exceptions (>=0.10.4 && <0.11), filepath (>=1.4.2 && <1.5), servant-serf [details]
License MIT
Maintainer ACI Learning
Category Web
Source repo head: git clone
Uploaded by fozworth at 2022-09-22T18:04:28Z
Distributions NixOS:
Executables servant-serf
Downloads 945 total (29 in the last 30 days)
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Status Docs available [build log]
Last success reported on 2022-09-22 [all 1 reports]

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