How it works
From no AI account at all to a CSV of grades in about ten minutes. Free, and there is nothing to sign up for.
The five steps
Get an API key (free with Gemini)
On the Grade page, step 3, choose "I need a key". The walkthrough takes you to Google AI Studio, where any Google account gets a free key with no card. Paste it back into OpenGrader. Left alone, the key is held for that tab only. Tick "Remember this key on this device" and it is stored in that browser until you press Clear key — handy on your own computer, and the thing to leave off on a shared one.
Add your rubric
Paste it in, or upload a .txt, .docx, or .pdf. One line per criterion works best. OpenGrader scores against exactly the criteria you give it and does not add its own. A rubric has to fit inside 20,000 characters, and one submission inside 500,000 — roughly 80,000 words, so longer than anything a school assignment usually runs to; the counter under the box tells you where you are.
Pick the writing type
This adds genre checks like counterargument handling or textual citation. It is extra feedback only and never changes your rubric score.
Add the class set
Drop one file per student, or paste a single submission with a name. Names come from the filenames, so fix any that look off before you grade. Two submissions under the same name are flagged, because the export would carry both rows under it.
Grade, review, export
Press Grade. Rows fill in as they finish. Every score and comment is editable. When you are happy, download a CSV or copy a feedback report for a Google Doc. Some instances also offer a one-click send to a Google Sheet in your own Drive; where that button is greyed out the site operator has not set it up, and the CSV imports into Sheets just as well.
Questions
Does this cost anything?
OpenGrader is free and there is no sign-up — no account, no card, nothing to cancel. You pay only for the AI usage on your own key. A Gemini key is free within a generous limit. A class set on Claude or GPT runs a few cents.
Where does the student writing go?
Pressing Grade sends your rubric, the essay and your key from your browser to OpenGrader, which relays them to the AI provider you picked and hands the grade back — a browser cannot call those APIs directly. Nothing is written to disk, there is no database, and nothing about the text or your key is logged. It exists in memory for one request and is then dropped. The provider itself does read the essay, under your own account and its terms. Your work stays in this tab until you close it.
Is my API key kept anywhere?
By default it is held for the tab you are working in and goes when you close it. Tick "Remember this key on this device" and it is stored in that browser instead, and is still there next time you open OpenGrader, until you press Clear key. That is the option to leave off on a shared or school computer.
A row failed. What now?
The rest of the class keeps grading, and when the pass finishes the failed row offers a Retry. Most failures are worth one — a slow provider, a dropped connection. Two are not. A message about a character limit means the rubric or that one submission is too long, and a message about the key means the key is wrong or has no billing set up. Fix those above and grade again; retrying on its own will never clear them.
Can I trust the grades?
Treat them as a fast first pass. Every score points back to a line from the student’s own writing, so a bad call is quick to spot. You review and adjust before anything leaves the page.