Castwyn
AI content engineAbout
Built by one person, for people posting alone.
Castwyn is run by Blake Murphy. It is not a venture-funded platform with a growth team — it is a tool built by someone who needed it.
Why it exists
Showing up consistently across five or six networks is not a discipline problem. It is a volume problem. Writing natively for each platform takes longer than having the idea did, so most people either post the same text everywhere and watch it flop, or they quietly stop.
Castwyn exists to close that gap: one idea goes in, and a week of posts comes out — each written for the network it is going to, in a voice you configure, scheduled and published for you.
The three decisions that shape it
Bring your own keys. Most tools resell AI credits at a markup and then meter your usage, so writing more costs more. Castwyn charges a flat price for the software and lets you pay your AI provider directly, at cost. It makes less money per customer on purpose.
Say what actually works. Some networks allow automatic publishing. Some do not, and some still owe an app review. Rather than call all of it “automation,” the product and this site label which networks publish on their own and which are one-click copy-and-paste. It costs signups. It keeps the ones who stay.
Nothing gets sold that is not built. Features that are still in progress are marked as such and cannot be purchased, even when the code to charge for them exists. If a plan lists something, it works today.
What that means for you
You are dealing with the person who wrote the code. Support is not a queue at a company that outgrew its customers — it is one email to someone who can fix the bug the same day. That is an advantage now, and it is honest to say it will change if Castwyn grows.