How to specify default format for FOS\RestBundle to json?

The final answer is much easier and is irrelevant to FOS\RestBundle:

api:    resource: "@APIBundle/Controller/"    type:     annotation    defaults: {_format: json} # <<<<<<<    prefix:   /api/

You may specify a default_format that the routing loader will use for the _format parameter if none is specified.

# app/config/config.ymlfos_rest:    routing_loader:        default_format: json

By default, routes are generated with {_format} string. If you want to get clean urls (/jobs instead /jobs.{_format}) then all you have to do is add some configuration:

# app/config/config.ymlfos_rest:    routing_loader:        include_format:       false

Have a look at the FOSRestBundle documentation for more informations.

I couldn't test this solution myself but following the documentation it seems that you can use a default format by giving rules on path

config.yml

fos_rest:    format_listener:        rules:            # setting fallback_format to json means that instead of considering            # the next rule in case of a priority mismatch, json will be used            -                path: '^/'                host: 'api.%domain%'                priorities: ['json', 'xml']                fallback_format: json                prefer_extension: false

With such, a request made with Accept-headers containing

text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8,application/json

Will result in a json Request format