Session muscle summary
End a workout with a picture of what it worked — the screen people screenshot and send to someone.
The most shareable screen in a fitness app is the one at the end.
A summary of what a session worked is a single figure with the muscles lit, and it carries further than a list of sets does — it is readable at a glance, in a notification, and at the size a chat app shows.
Render front and back
A session usually reaches both sides of a body. Render both and put them side by side:
/v1/{key}/body/female/front.webp?primary=quads&secondary=abs&w=480
/v1/{key}/body/female/back.webp?primary=glutes,hamstrings&secondary=lower-back&w=480Use primary for what the session actually loaded and secondary for what it
supported. The distinction is what makes the picture read as a summary rather than as
a diagram.
Serve smaller sizes for lists
The same URL serves a history row or a notification at a smaller width, and cropping to the highlight makes it legible where a whole figure would not be:
/v1/{key}/body/female/back.webp?primary=glutes&crop=primary&w=96Handle missing highlights
A muscle the sheet does not draw comes back in an x-muscles-not-drawn header rather
than as an error. A summary from a varied session renders what it can instead of
failing on one id.
If an allowance is exhausted the figures still render, in a reduced form — a summary screen never arrives empty. See rate limits and allowances.