I'm assuming he's just talking about producing an API endpoint. Sort of, a URL which supports a GET request and returns a valid format (JSON). No library needed.
Pretty much what you have here (
http://loyce.club/Merit/merit.all.txt), just converted to a JSON format w/ the ability to filter based off parameters (sending user, receiving user, etc)
It could be done w/ 1 front-facing PHP script.
I don't know JSON/PHP (and don't really have the time to learn it now), so it's not something I can easily produce. But if someone (you?) wants to create it based on the full Merit data, go ahead. I can create for instance api.loyce.club to host it. Just tell me what I need to do

Has been a while since I did PHP but I hope this helps:
header("Content-type:application/json");
//dtg, merit, msg, giver, receiver
$url = "merits.txt";
$file = file($url);
$file = str_replace(" ", ",",$file);
$file = str_replace("\r\n", "",$file);
$jsonObj = array();
foreach ($file as $line => $value) {
$value = explode(",", $value);
// unsorted (line numbers)
//$file[$line] = array("DTG" => $value[0], "Merit" => $value[1], "Message" => $value[2], "Donor" => $value[3], "Receiver" => $value[4]);
//array sorted by DTG
$jsonObj[]= array($value[0] => array("Merit" => $value[1], "Message" => $value[2], "Donor" => $value[3], "Receiver" => $value[4]));
}
echo json_encode($jsonObj, JSON_PRETTY_PRINT);
?>

Seems to work, could be improved for sure. But otherwise ... it has been a while. Besides this and as already stated, it would be much faster to send individual request to the database (e.g. by GET).
If you tell us the structure of the database, it is actually super easy to implement.
I have forgotten my actual request for this topic ...

Got it again:
Sometimes quoting a full text makes posts less well structured. While there is a function to full-quote other posts, I would like to have a function to mark and insert text you actually want to quote from other posts.