Running alongside the other SEO plugins

The short answer has not changed: run one SEO plugin at a time. This page exists so you can see exactly what happens when you do not, and so a bug report can say "this pairing, this version, this tag" instead of "it conflicts".

Four things were checked for each of the four plugins:

• What the <head> of a single post looks like with both plugins active, tag by tag.
• Which plugin ends up owning /sitemap.xml, and what robots.txt ends up advertising.
• How many per-post fields the one-click migration actually carries over.
• How many fields the read-fallback picks up while both plugins are still installed.

Results below were produced on 17 October 2026 against these exact versions. If you are reporting something that disagrees with this page, please include your equivalent list.

Each competitor was activated on its own, alongside Flexa SEO, with default settings and no setup wizard run. A single published post was requested over HTTP and the head tags counted. The plugin was then deactivated before the next one was activated, so no two competitors were ever live together.

How many times each tag appeared in the <head> of one published post. One is correct. Anything higher means both plugins emitted it and search engines get to pick.

The ones in the Yoast column are not Yoast behaving better. They are Yoast declining to emit a tag it had no value for on an unconfigured install. Give it a description and the count goes to two like the rest.

Reproduce it on your own site with nothing more than curl:

curl -s https://example.com/your-post/ \
  | grep -c '<link rel="canonical"'

curl -s https://example.com/your-post/ \
  | grep -io '<meta name=.robots.[^>]*>'

Flexa SEO serves its sitemap index at /sitemap.xml. That is the same address SEOPress and All in One SEO want, while Yoast and Rank Math use /sitemap_index.xml.

While Flexa’s sitemap is on, core’s own /wp-sitemap.xml is switched off, so the site has one index rather than two listing the same URLs, and robots.txt advertises one address. If you need core’s back, return true from flexa_seo_aeo/sitemap/keep_core_sitemap.

All in One SEO is the one hard route conflict in the set. It claims /sitemap.xml and wins it, so Flexa’s sitemap becomes unreachable, and its robots.txt handling drops Flexa’s sitemap line entirely. Nothing in either plugin tells you this has happened.

Settings → Migration copies another plugin’s per-post fields into Flexa’s own. Eleven fields were written on a test post for each source, then migrated and read back.

Template tokens are converted as part of the move. Rank Math’s single-delimiter %sitename% becomes %%sitename%%, and names that differ between vocabularies are mapped across, so SEOPress’s %%post_title%% becomes %%title%% and its %%sitetitle%% becomes %%sitename%%. A token with no equivalent resolves to an empty string rather than printing itself.

SEOPress migration shipped in 1.0.0. Its column was measured on 20 October 2026, against SEOPress 10.1 on the same install: all eleven fields were written on a test post, migrated and read back, and a second run skipped the post as already migrated. The Yoast and Rank Math columns are from the earlier runs described above.

Migration never deletes the source plugin’s meta. You can run it, check the result, and deactivate the old plugin afterwards, in that order.

Separately from migration, Flexa reads another plugin’s meta on the fly when a post has nothing of its own. This is what keeps the front end intact the moment you activate Flexa, before any migration has run. It covers fewer fields:

A report that can be acted on without a round trip contains these five things:

• Versions of WordPress, PHP, Flexa SEO and the other plugin, in the shape of the baseline table above.
• The URL of a page where you can see it, if the site is public.
• Which tag or route is wrong, and what you expected instead. A grep -c count is worth a paragraph of description.
• Whether the other plugin was configured or left at defaults.
• Whether it still happens with every other plugin deactivated and a default theme active.

Pairings already on this page do not need re-reporting unless your result differs from what is written here. A result that differs is exactly the interesting case.