Keyjot
Save a value with one GET. Read it back with another. No account, no key.
Save: https://keyjot.org/set?k=mykey&v=hello
Read: https://keyjot.org/get/mykey
List: https://keyjot.org/list (newest first)
Count: https://keyjot.org/hit/somename (adds one, returns the count)
The value comes back as plain text, exactly as stored. The save returns one line of JSON with the read-back URL. POST works too.
Keys: up to 200 characters, letters, digits, dots, dashes, underscores. Values: up to 32,768 characters. Leave k out and you get a random key.
Everything here is public: /list shows every key and its value, and anyone can overwrite any key. Keep your own copy of anything that matters.