Where does my API key go?

It stays in your browser and is sent only directly to OpenAI or Anthropic for these requests. It is never stored, logged, or sent to any Gera server.

How does the variable substitution work?

Every {{...}} slot in your template is replaced with the current line from the values box. Each line produces one independent request, so a 20-line list runs 20 prompts.

Why limit parallel requests to five?

Provider APIs enforce rate limits, and the browser can only hold a handful of connections to one host efficiently. Capping at five avoids 429 errors while still being much faster than one at a time.

Can I use this for thousands of inputs?

It is built for tens to low hundreds of inputs run interactively. For very large jobs use the provider's dedicated Batch API from a server, which is cheaper and more reliable.

Batched Prompt Runner (BYO-key)

What this tool does

When you want to apply one prompt to many inputs — summarise 50 reviews, classify 30 support tickets, generate taglines for a product list — running them one at a time in a chat window is painfully slow. This tool turns a single prompt template plus a list of values into a batch of API calls and runs them in parallel against your own OpenAI or Anthropic key, showing each result in its own row.

Everything happens in your browser. Your key is used only for the direct provider request and is never stored.

How it works

You write a template containing a {{variable}} slot, for example:

Classify the sentiment of this review as positive, negative, or neutral: {{review}}

Each non-empty line in the values box is substituted into that slot to produce one prompt. The runner then dispatches requests with a small pool of workers — you choose between one and five in flight at once — so the batch finishes quickly without tripping provider rate limits. Each row updates independently to running, done, or error, and failed rows show the provider’s error message so you can see exactly which input broke and why.

Tips and limits

Keep concurrency at 2 for free-tier or low-rate-limit keys, and raise it only if you are not seeing 429 errors.
Put any fixed instructions (format, tone, length) in the template itself so every request is consistent — the only thing that should change between rows is the substituted value.
For genuinely large jobs (thousands of rows), use the provider’s server-side Batch API instead: it is roughly half the cost and designed for volume. This tool is the fast interactive option for everyday batch work.