SumizAI vs GPT-Prompter

What GPT-Prompter is

What GPT-Prompter is

GPT-Prompter is a Chrome extension letting you use GPT-3, GPT-4, and the ChatGPT API without visiting the OpenAI website, with no added middleman costs and no reliance on someone else's infrastructure — the connection goes directly to the user's own API key. The project, open source under the user giosilvi on GitHub, is a simple but effective bridge between selected text on a page and a language model.

Key features

Selecting text on any page and choosing the GPT-Prompter command from the right-click context menu sends a custom prompt along with the selected content. Prompts can be freely customized using the #TEXT# placeholder, which gets replaced with the actual selected fragment of the page. Setup comes down to clicking the extension icon, entering your own API key, and optionally selecting text before invoking the command from the menu.

Who it's for

GPT-Prompter appeals to people who regularly need quick access to a language model for a selected fragment of a page — translation, summary, explanation — without copying text into a separate chat window every time.

Use cases

In practice, GPT-Prompter works well for quickly translating a selected paragraph on a foreign-language page, summarizing a long article fragment without leaving the browser tab, and building a personal library of reusable custom prompts with the text placeholder.

Pricing and business model

The extension is free and open source — the only cost is your own OpenAI API key's usage, billed directly by OpenAI at standard API rates, with no middleman markup.

Limitations and what to watch for

Needing your own OpenAI API key means an extra setup step and direct responsibility for usage costs, which solutions with built-in, paid model access avoid. The extension works in Chrome only, with no version for other browsers.

AI notes from selected page fragments

GPT-Prompter offers no lasting notes system of any kind — an answer about a processed page fragment you want to keep as an ai notes entry has to be copied by hand into a separate notes app once you get the result.

Your own API key as a middleman-free model

The decision to require your own API key instead of built-in, paid model access is the same "bring your own key" approach that eliminates a middleman's markup and gives the user full transparency into the real cost of queries.

What's worth checking before choosing

Before installing, check whether you already have your own OpenAI API key, and review current API pricing to estimate the typical monthly cost of using the extension.

Bottom line

GPT-Prompter is a lightweight, free extension for quickly sending selected text to an OpenAI model on your own API key, at the cost of no notes system and being limited to Chrome. Anyone who wants ai notes from such answers to land automatically in an organized archive needs a separate notes app.

Comparison with SumizAI

GPT-Prompter and SumizAI share a middleman-free, bring-your-own-key philosophy, but differ in scope. GPT-Prompter is an extension for quick, one-off queries about selected text on a page. SumizAI is a notebook where a conversation with an AI model — on your own API key to one of seven providers — automatically turns into ai notes saved as Markdown files in the user's vault, with a title and place in the table of contents assigned without manual work. Anyone who wants quick model access for selected text will pick GPT-Prompter; anyone who wants these notes from full AI conversations to build a lasting archive will find SumizAI the better-fitting tool.

What SumizAI is

A note-taking application built around a conversation with an AI model. You ask a question, the answer streams back, and the answers worth keeping become Markdown notes — filed into a vault that is a folder on your own disk.

A vault is a directory holding base.md, a generated table of contents up to six levels deep, and a notes/ folder with one .md file per note. Before a note is written it is checked against the ones already there, so the fourth note about the same idea gets merged instead of added. Links between notes are ordinary Markdown links to files that exist.

The model is never ours: you bring your own API key to one of seven providers — Anthropic, OpenAI, Gemini, Groq, OpenRouter, a local Ollama or your own server — and pay that provider directly. A question sends the table of contents plus at most five relevant notes within a 24,000-character budget, and the app shows you which five it used.

Every answer kept this way becomes one of these ai notes, ready to search again months later without hunting back through old chats.

Side by side

Where they differ

• GPT-Prompter is a place to have the conversation. SumizAI is not a chatbot — the conversation is the input, not the product. What comes out of it is a .md file with a title, a place in base.md and a duplicate check against the notes already in the vault. If you only want to talk to a model, you do not need SumizAI.
• GPT-Prompter is open source (MIT), and SumizAI is not. If reading the source is what decides it for you, that is a real argument for GPT-Prompter. The guarantee SumizAI offers instead is structural rather than legal: the notes are Markdown files in a folder you chose, so they open in any editor whether or not the application is running.
• AlternativeTo's description of GPT-Prompter does not mention Markdown, so check what format your notes end up in before you fill it up. SumizAI writes standard .md files to a folder you picked, and an unpaid account can still export all of them.
• GPT-Prompter is extensible through plugins. SumizAI is not, and that is a genuine trade: you cannot bend it into something else, but there is also no plugin to keep working after the next release. What it does instead is fixed and small — a chat, a filing rule and a folder of Markdown.
• AlternativeTo lists no mobile version of GPT-Prompter. SumizAI runs on macOS, Windows, iOS and Android.

Which one to pick