New page: Webhook Message Formats A chat format is nothing but a JSON body template with a {{message}} slot, so they're data now, not a PHP switch — add any platform without a release. Covers: the idea; the five fields; ready-to-paste templates for Google Chat, Mattermost, Rocket.Chat, ntfy, Telegram, PagerDuty and a Discord rich embed (showing static fields and merge codes inside a template); the escaping guarantee (decode -> substitute into values -> json_encode, never splice raw text, with the injection test shown); the engine's hardcoded fallback; why the built-ins are locked and Copy exists; and why the URL pattern and formatting hint exist at all (both are bugs Ed hit today). Webhooks.md section trimmed to a summary pointing here. Sidebar updated.