Compare two prompt versions side-by-side and see the token and cost impact of the change before you ship it.
3 added 2 removed
~15 tokens
~38 tokens (+23)
1+You are a helpful, expert assistant.
2+Answer the user's question concisely, in markdown, and cite sources when possible.
3+If you are unsure, say so instead of guessing.
1-You are a helpful assistant.
2-Answer the user's question concisely.
Requests per day
Monthly input-cost delta from this edit
+$1.73
Cost delta covers input tokens only (the prompt itself), at the selected model's list price — output tokens aren't affected by a prompt edit alone.
About Prompt Differ
Small prompt-engineering edits — an added instruction, a longer system message, a few-shot example — quietly change your per-request token cost. Prompt Differ shows a line-level diff between two prompt versions and translates the change into a token delta and projected monthly cost impact at your traffic volume, so prompt reviews can weigh cost alongside behavior.
Key Features
Line-level diff with added/removed counts, same visual style as a git diff.
Token delta and monthly input-cost impact at a chosen request volume.
100% client-side — prompts never leave the browser.