I kept finishing long ChatGPT/Claude sessions having learned a lot but unable to find any of it later. The linear chat format was the problem: tangents bury your place, and the model blends your careful deep-dive with an unrelated detour from ten messages ago. fork.ai answers a question as structured sections instead of one blob. From any section you can "go deeper" into a child node, or highlight a sentence and branch a follow-up anchored to exactly that text. Every branch becomes a node on a live mind map, and each branch only inherits its own context lineage — so answers stay sharp as you go deeper instead of degrading. Stack: Next.js 15 + NestJS, DynamoDB single-table, streaming SSE for the root answer. Branch calls run on a model you pick (Claude / Gemini / DeepSeek / GLM); root is Claude Sonnet. You can export a session to Notion or PDF. It's free to try (no signup needed for a first session). I'd genuinely love feedback on the branching UX and where it breaks down. Happy to answer anything about the architecture.

fork ai

Branch any AI answer into a mind map you can keep

Branch any AI answer into a mind map you can keep