Most of the SEO tools (and WordPress plugins) generate an XML file for the sitemap. However, it’s perfectly fine to keep the sitemap in a simple text file that contains one URL per line.

If you are using Nunjucks as a templating engine, this is one of those rare cases when you have to care about the whitespace control.

As comparison, with the “regular” for loop tag:

{% raw %}

{% for post in collections.sitemap %}
{{ post.url }}
{% endfor %}

{% endraw %}

the output looks like this:

https://www.implenton.com/configure-netlify-to-run-php/

https://www.implenton.com/cube-css-fresh-ideas/

The empty line before the first URL, between the URLs and after the last one, is part of the output. It’s not a formatting mistake in this article.

This does not conform to the requirements, as we need exactly one URL per line without empty lines.

You can control the whitespace by adding a minus sign (-) to the start ({% raw %}{%{% endraw %}) or end block ({% raw %}%}{% endraw %}). If you add it, then it will strip all leading or trailing whitespace.

Here’s what worked for me to generate the sitemap.txt:

{% raw %}

{%- for post in collections.sitemap -%}
{{ post.url }}
{% endfor -%}

{% endraw %}

Notice how the beginning of the endfor does not have the - sign, but the rest do.

This resulted in the correct output, without empty lines:

https://www.implenton.com/configure-netlify-to-run-php/
https://www.implenton.com/cube-css-fresh-ideas/