AI DEVELOPMENT WORKSPACE
Prompt Template Builder
Replace literal named placeholders with supplied string variables.
Input is processed on this site only when you run the tool. The application does not save inputs or results.
input.txt
changed.txt
Result result.txt
A little clarity goes here.
Run the tool to see your result.
Result preview
UTF-8 text, at most 32768 bytes per input. Tab leaves the editor. Plain text disables syntax colors. Browser textareas may normalize line endings to LF.
{"render":{"inputMode":"pair","options":[],"inputLabels":{"input":"Template","input2":"Variables JSON object"}}}{"render":{"input":"Review {{language}} code for {{topic}}.","input2":"{\"language\":\"PHP\",\"topic\":\"clear error handling\"}","options":[],"output":"Review PHP code for clear error handling."}}A QUICK WALKTHROUGH
A familiar workflow,
with room to focus.
Write literal placeholders such as {{language}} in the template.
Supply a JSON object of string variables.
Render once; inspect the result before using it elsewhere.
When to use Prompt Template Builder
Assemble repeatable prompt text from named fictional values without introducing an expression language.
Read the result
Only exact {{name}} placeholders are substituted once. Braces inside a variable stay literal, unused variables are allowed, and missing or malformed placeholders reject the render.
SEE IT IN PRACTICE
Worked examples
Sample input. A result you can inspect.
Render example
Template
Review {{language}} code for {{topic}}.Variables JSON object
{"language":"PHP","topic":"clear error handling"}Expected result
Review PHP code for clear error handling.
Formats, limits and common errors
Check exact placeholder spelling and string-valued variables. Rendered text remains untrusted data.
- At most 32,768 bytes per input, 128 variables and 1,000 placeholders. Names use ASCII letter/underscore followed by letters/digits/underscore, at most 64 characters.
- Exact {{name}} syntax only. Missing names, malformed delimiter pairs, duplicate keys and nonstring values reject. Unused variables are allowed. Single braces are ordinary text.
- Variable text is inserted literally in one pass, including braces or code-like text. No recursive substitution, expressions, includes, file access, prompt execution or AI calls. Normal output limits prevent expansion abuse.
- Input: 32,768 UTF-8 bytes per text field. Output: at most 524,288 UTF-8 bytes; serialized responses have a separate 1 MiB ceiling. Size/work failures return no partial result.