Prompt Template Filler AI & Writing
Fill {{variables}} in a prompt template from a list of values, and generate every version at once.
Prompt Template Filler is a free online tool that fill {{variables}} in a prompt template from a list of values, and generate every version at once. It runs entirely in your web browser using plain JavaScript, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free — no account, no quota, no watermark
- Category
- AI & Writing
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Technology
- plain JavaScript
- Settings
- 2
- Works offline
- Yes, after the first visit
About Prompt Template Filler
Evaluating a prompt properly means running the same wording against a spread of inputs, not one. Editing the same sentence forty times introduces a typo somewhere around the twelfth and quietly invalidates the comparison. This expands a `{{placeholder}}` template over a list of values so every version is identical apart from the thing you meant to vary.
How to use it
- Paste the text you want to run through prompt template filler.
- Set values — one row per prompt, comma separated, in placeholder order and separate output prompts with.
The 2 settings
| Setting | What it does | Default |
|---|---|---|
| Values — one row per prompt, comma separated, in placeholder order | Free text. | running shoes, marathon runners
noise-canceling headphones, commuters
a standing desk, remote workers |
| Separate output prompts with | Choose from 3: A horizontal rule, A blank line, A numbered heading. | A horizontal rule |
Under the hood
| Runs on | plain JavaScript — runs the whole thing |
| Controls | Values — one row per prompt, comma separated, in placeholder order, Separate output prompts with |
Questions
What placeholder syntax does it use?
Double curly braces — `{{product}}` — which is the Mustache and Handlebars convention and the one most prompt tooling has settled on. Placeholder names are matched case-insensitively and can contain letters, digits and underscores.
How do values map to placeholders?
By position. The first comma-separated value on a row fills the first placeholder in the template, and so on. A row with fewer values than there are placeholders leaves the extras in place rather than substituting blanks, so the gap is visible.
What if my values contain commas?
They will split at the comma, since the row format is comma separated. Use a template with one placeholder and put each full value on its own row, or substitute a different separator in the values before pasting.