Your own roproxy.

How it works

Swap https://SERVICE.roblox.com/PATH for https://roproxy.davibevilla.com/SERVICE/PATH.

Example: https://friends.roblox.com/v1/users/1/followers/count → https://roproxy.davibevilla.com/friends/v1/users/1/followers/count

Send your key in the X-Api-Key header (or ?key=). Get one with /keys in Discord or at bot.davibevilla.com/keys.

Limits per key: 60 a minute, 2,000 a day. Answers are cached for a few seconds to a few minutes, so asking the same thing again is fast. Every answer has an X-RateLimit-Remaining header.

Luau example

local HttpService = game:GetService("HttpService")
local KEY = "rpx_your_key_here" -- keep it in a SERVER script, never a LocalScript
local BASE = "https://roproxy.davibevilla.com"

-- does this player follow someone? (goes through every page of who they follow)
local function isFollowing(playerId, targetId)
	local cursor = nil
	for page = 1, 20 do
		local url = BASE .. "/friends/v1/users/" .. playerId .. "/followings?limit=100&sortOrder=Desc"
		if cursor then url ..= "&cursor=" .. cursor end
		local ok, body = pcall(function()
			return HttpService:GetAsync(url, true, { ["X-Api-Key"] = KEY })
		end)
		if not ok then return nil end -- could not check right now: try again later
		local data = HttpService:JSONDecode(body)
		for _, user in data.data or {} do
			if user.id == targetId then return true end
		end
		cursor = data.nextPageCursor
		if not cursor then return false end
	end
	return false
end

Turn on Allow HTTP Requests in Game Settings → Security.

Errors

401 no key / wrong key · 403 not an allowed endpoint · 404 unknown service · 429 too many requests (wait, or tomorrow) · 502 Roblox did not answer. Anything else is Roblox's own answer, passed straight through.