apilayer.com
In short: Getting listed on APILayer Marketplace is free. Plan for about 45 minutes — there is material to prepare and a review to wait on.
What they ask for: Publish a stable, documented your tool API and apply as a provider with examples, uptime, support, and honest pricing.
Publish a stable, documented your tool API and apply as a provider with examples, uptime, support, and honest pricing.
A deployed API, test environment, documentation, performance, and review are required; duplicate or weak APIs may be rejected.
Open the submission page on apilayer.com and complete its form — that is the "Open submit page" link at the top of this page.
A deployed API, test environment, documentation, performance, and review are required; duplicate or weak APIs may be rejected.
Priority sets the band — this one is high. Cost (free) and effort (moderate) move it within that band, which puts it in the high impact tier. The score orders a submission queue. It is not a measure of the site’s domain authority, traffic or quality.