Your files stay on your device

Prompt template builder

Build prompt templates with typed variables, defaults and conditional sections, then render them against test cases and export JSONL for evaluation runs.

Add a template and at least one test case to render it.

Rendering is plain text substitution: no model is called and no tokens are counted, so judge the output size yourself or pair this with the tokenizer. The variables JSON doubles as the template's schema, and the test-case JSON doubles as its regression suite: a template change that breaks a case shows up here as a missing value or a type error. The template JSON export is the schema plus template text for version control, and the JSONL export feeds evaluation runs one prompt per line.
Options

More AI tools

- Chat template renderer (/ai/chat-template)
- Fine-tune JSONL formatter (/ai/jsonl-formatter)
- Tokenizer playground (/ai/tokenizer)
All AI tools (/ai)

Was this tool useful?
YesNo

Canonical HTML: https://nutter.tools/ai/prompt-template-builder
Markdown version: https://nutter.tools/ai/prompt-template-builder.md
Plain-text version: https://nutter.tools/ai/prompt-template-builder.txt
Agent index: https://nutter.tools/llms.txt