Send the client a Plausible share link. They paste it into Tracksible. Do not send the Stats API key that can see every site. Revoke the link in Plausible when the work ends.
Do not send the key that can see every site
A Stats API key is an administrator secret. A client who only needs last week’s visitors does not need it. If the key leaks, every site on that account is in play.
A share link is scoped to the dashboard Plausible attached to that link. That is the secret to send.
Create a share link in Plausible, then open it in Tracksible
Create the shared dashboard link in Plausible, or use one you already have. Send the link. The client installs Tracksible when a listing is available, chooses Share link, pastes the complete link, and connects.
There is no Tracksible account for them to join. The share-link dashboard page matches this flow. Compare both connection types in share link vs API key.
What the client can and cannot do
They can view what that link allows. They cannot administer your Plausible account through Tracksible. Available metrics still depend on plan, permissions, server version and connection type.
They do not need your API key. A client who only has one site can stay on Free.
Revoke access in Plausible, not only on the phone
Deleting the site on the phone does not revoke the link. Anyone who still has the live link can open the dashboard. Revoke or replace it in Plausible.
Removing the app does not delete your Plausible account. For records Webjuice may hold, see delete your data.
When the agency should use Pro
Free is one site. An agency switching between client dashboards needs Pro for unlimited sites. Home screen widgets also require Pro. Pro is a one-time $9.99 in-app purchase, not a subscription. The store shows the local price.
Read the agency page and pricing. Purchases do not transfer between iOS and Android.