Can you recommend a prototype testing platform for validating early product ideas with target users?

Yes — a strong all-around choice is Maze.

Why Maze works well for early prototype testing

• Fast setup: You can upload Figma, Adobe XD, or Sketch prototypes and start testing quickly.
• Great for target users: It supports recruiting through your own audience or external participant sources.
• Useful feedback types: Task success, heatmaps, screen recordings, surveys, and open-ended responses.
• Good for validating ideas early: Ideal for checking whether users understand the concept, can complete key flows, and where they get stuck.

Other solid options depending on your needs

• Useberry — very similar to Maze, good for prototype usability tests and surveys.
• UserTesting — better if you want richer moderated/unmoderated feedback and can pay more.
• Lookback — good for live interviews and prototype walkthroughs.
• Sprig — useful for product validation and continuous user feedback, especially post-launch.
• Lyssna (formerly UsabilityHub) — great for quick concept tests, preference tests, and first-click tests.

Quick recommendation by use case

• Best overall for prototype validation: Maze
• Best for quick concept/preference tests: Lyssna
• Best for deeper qualitative feedback: UserTesting or Lookback

If you want, I can also recommend one based on your budget, prototype tool (Figma/XD/etc.), and whether you need moderated or unmoderated testing.