How to prepare API from existing DB in 5 mins?

Taleh Ibrahimli
2 min readApr 23



With help of API Brew, you can build API from your existing DB. In this article, we will show you how to do it.


  • API Brew server is running and accessible
  • dhctl is installed
  • You have an existing DB

For installing API Brew server, please refer to Installation

Connect API Brew to your exising DB

We need to prepare new Data Source for our DB. For this, we will use dhctl.

type: datasource
name: mydb
host: localhost
port: 5432
dbName: dh_db_2
username: root
password: root

Now let’s test connection to our DB

dhctl data-source status --name=mydb

You will see following output

INFO[0000] DataSource name: mydb                        
INFO[0000] ConnectionAlreadyInitiated: false
INFO[0000] TestConnection: true

Prepare API from DB

Let’s assume that, we have author table in DB, and we want to expose it as API. For testing purposes you can execute this query on DB to have author table

create table
id bigserial primary key,
name character varying(255) not null,
description character varying(255)

Now, let’s see what tables we have in our DB, We will get this information from API Brew client

dhctl data-source list-entities --name=mydb

You will see following output

public author editable
dhctl data-source prepare --name=mydb > schema.yml

This command will generate schema.yml file, which contains all information about resources for our DB.

The schema.yml file will look like this

AutoCreated: "true"
DisableVersion: "true"
name: author
namespace: default
- annotations:
Identity: "true"
SourceDef: int8
mapping: id
name: id
primary: true
required: true
type: INT64
- annotations:
SourceDef: varchar(255)
length: 255
mapping: name
name: name
required: true
type: STRING
- annotations:
SourceDef: varchar(255)
length: 255
mapping: description
name: description
type: STRING
catalog: public
dataSource: mydb
entity: author
type: resource

Now, let’s apply our resources

dhctl apply -f schema.yml -m=false

Test API

So, Bingo! We have our API ready. You can check it by visiting Swagger UI

You can use following url to see swagger UI http://localhost:9009/docs/index.html

You can also call curl directly to see the result

## Create author
curl -X 'POST' \
'http://localhost:9009/author' \
-H 'accept: application/json' \
-H 'Authorization: Bearer <token>' \
-H 'Content-Type: application/json' \
-d '{
"description": "123",
"name": "abc"
## List authors
curl -X 'GET' \
'http://localhost:9009/author' \
-H 'accept: application/json' \
-H 'Authorization: Bearer <token>'


With help of API Brew, you can build API from your existing DB. In this article, we have shown you how to do it.

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