Crystal library to create REST API with Kemal
Switch branches/tags
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.

kemal-rest-api Build Status

A Crystal library to create REST API with Kemal.

See examples folder for mysql, sqlite3 and mongo samples.

NOTE: this is a beta version, a lot of features and security improvements need to be implemented actually


Add this to your application's shard.yml:

    github: blocknotes/kemal-rest-api


require "db"       # dependency required to use CrystalDbModel
require "sqlite3"  # dependency required to use CrystalDbModel - alternatives: crystal-mysql, crystal-pg
require "kemal"
require "kemal-rest-api"

class MyModel < KemalRestApi::Adapters::CrystalDbModel
  def initialize
    super "sqlite3:./db.sqlite3", "my_table"

module WebApp
  res =, KemalRestApi::ALL_ACTIONS, prefix: "api", singular: "item"

Generated routes:

GET    /api/items
GET    /api/items/:id
POST   /api/items
PUT    /api/items/:id
DELETE /api/items/:id

KemalRestApi::Resource options

  • json (Bool): form payload as JSON instead of formdata, default = true
  • plural (String): plural name of the model, used for routes, default = singular pluralized
  • prefix (String): prefix for all API routes, default = ""
  • singular (String): singular name of the model, default = class model name lowercase

More examples

See examples folder.


crystal-db shard is required only if KemalRestApi::Adapters::CrystalDbModel is used.

The proposed adapters are basic implementations, you can create easily a model adapter that responds better to your needs. prepare_params is used to adjust the create/update parameters.