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Prompt Declaration Language vs Langflow: catalog facts
Prompt Declaration Language	Langflow
Free Free to use; model providers it calls may charge separately.	Free Free and open source under the MIT license.
macOS, Command line	Web, Self-hosted
Prompts written as declarative YAML with enforced structure Not tied to a particular programming language	Visual canvas plus built-in API and MCP server output Supports a large library of LLMs, vector databases and tools
Requires learning a new YAML-based language Aimed at developers rather than everyday AI users	Requires separate access to whichever LLM providers or local models you connect Complex workflows can require developer-level setup
Downloadable app	Self-hosted, Web application
Closed source	Open source
License not stated	License: MIT
Not stated if an account is needed	Not stated if an account is needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked October 2, 2026	Official website Full listing and sources Checked September 22, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.