The request "Flatter" names no clear product, and none of the candidates is a tool for flattering text or images. Flatterer is mentioned only as a sibling open-source project of its developer 1, and the rest are general platforms or unrelated tools, so the nearest matches are below. Please say what you want flattered (a photo, a 3D or music score, text, or a data flattening step) so I can recommend the right tool.

A question back: What do you want flattened: a photo or image, a 3D model, text or data, or a music score? The candidate list above does not show a tool that flattens any of these.

1. 1

   Flattererstuvel.euwebsite read, tools not yet checked

   Named on the developer's page as one of his open-source projects, but the source gives no description of what it does, so it may not be a fit for the request 1.

   Website

2. 2

   Flatflat.ioverified and signed

   Music notation software for web, desktop and mobile that lets users compose, edit and print sheet music 7, which is relevant only if "flatter" means a score or a music-theory flat.

   WebsiteDocsPricingGet started

   official:API · Flat API

   for agents: removeOrganizationUser · updateClass · createClass

3. 3

   Cloudflarecloudflare.comverified and signed

   A general cloud and edge platform with an MCP server and CLI 2; it does not show any flattening function for images or data.

   WebsiteDocsPricingGet started

   official:MCP server · @cloudflare/mcp-server-cloudflareCLI · cloudflaredskill · cloudflareskill · durable-objects+259 community tools built for it

   for agents: cloudflare-images-variants-variant-details-flat · flagship_evaluate_flag_post · flagship_list_flags