Prompt Builder – A block-based editor for composing AI prompts

Name: Prompt Builder – A block-based editor for composing AI prompts
Availability: InStock
Author: Jaber_Said

by Jaber_Said·Feb 12, 2026·1 point·0 comments

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AI Analysis

●●SolidSolve My ProblemNiche Gem

The Take

The block metaphor and live compiled preview are honest, practical improvements for anyone wrestling with long, conditional prompts — toggles for A/B testing and global {{vars}} are especially handy. Multi-model execution and editable response panes show the author thought about iteration and comparison, but the screenshot feels safe and functional rather than boldly new; I want to know how it handles collaboration, exports, and model/credit management.

Post Description

Hi HN,

I built Prompt Builder (https://www.promptbuilder.space/) because I was frustrated managing complex AI prompts in plain text boxes.

The core idea: instead of one giant textarea, you compose prompts from draggable, reorderable blocks. Each block can have its own XML/custom tags, visibility toggles (so you can A/B test sections), and duplicates.

Key technical details: - Live compiled preview: the right pane shows the exact string being sent, updating as you drag/toggle blocks - Dynamic variables: define {{var_name}} once, use across blocks, change in one place - Multi-model execution: send the same compiled prompt to different model APIs and compare outputs - Voice transcription + optional translation (useful for non-English prompt authoring) - Editable response pane: modify the model's output in place - Folder organization, search, and password-protected shareable links

I'd love feedback on the UX and whether the block metaphor resonates with how you think about prompt structure. What's missing?