What placeholder syntax does this use?

It uses double curly braces — write your variable name inside two opening and two closing braces, the same mustache-style syntax used by many prompt frameworks and templating libraries. The tool scans your template, finds every unique placeholder, and creates an input field for each one.

What happens if I leave a variable blank?

Unfilled variables are highlighted as missing and left as the literal placeholder in the rendered output, so you never silently ship a prompt with a forgotten value. Fill every flagged field before copying the final prompt.

Can I reuse the same variable more than once?

Yes. If a placeholder appears multiple times in the template, you fill it once and every occurrence is replaced with that value. This keeps repeated values such as a product name or user name consistent throughout the prompt.

Is my template or data sent anywhere?

No. All detection and substitution happens locally in your browser using JavaScript. Your template and the values you enter are never uploaded, so it is safe for confidential prompts and proprietary instructions.

Why use a template instead of editing the prompt directly?

Templates separate the stable instruction from the variable inputs, which prevents accidental edits to your carefully tuned wording, makes prompts reusable across many inputs, and gives you a clear checklist of what must be filled before each run.

Prompt Variable Injector

Reusable prompts have stable instructions and variable inputs. This injector lets you write a template with {{placeholder}} variables, fills in a form field for each one, and shows the fully rendered prompt live — flagging anything you forgot to fill.

How it works

Paste a template using double-brace placeholders. The tool scans it, extracts every unique variable name, and renders an input field for each. As you type, it substitutes values into the template and updates the preview. Any placeholder left blank is highlighted as missing and kept as a literal marker so you never ship a half-filled prompt. Everything runs locally — nothing is uploaded.

Tips and examples

A template like Summarize the following {{document_type}} for a {{audience}} in {{word_count}} words: exposes three fields. Reuse a placeholder anywhere in the template and it stays consistent — fill {{product}} once and every mention updates. This pattern is ideal when you run the same carefully tuned prompt over many inputs: the instruction wording stays locked while only the variables change, and the missing-field check acts as a pre-flight checklist before each call.