How to print pretty JSON on a html page from a django template?

Why not just use the pprint filter?

view

context["my_json"] = {i: i for i in range(100)}

template

<pre>{{ my_json }}</pre>
vs    
<pre>{{ my_json | pprint }}</pre>

Screnshot

Or if you want something even better, create a custom filter

templatetags/extras.py

import json

from django import template

register = template.Library()


@register.filter
def pretty_json(value):
    return json.dumps(value, indent=4)

template

{% load extras %}
<pre>{{ my_json | pretty_json }}</pre>

If you just want to keep your indent, You can use

return HttpResponse(json_pretty,content_type="application/json")

If it is a must to use django template, you can use the HTML <pre> tag as suggested by Klaus. So your template becomes

<pre>{{ json_pretty }}</pre>