Prismo — test your prompt changes before you ship

01 / REFRACTION

The prompt you meant to write.

Paste a draft, pick a goal. Prismo applies the craft — specificity, output format, role framing, constraints — without changing what you asked for.

DRAFTSummarize this article.

OPTIMIZEDSummarize the following news article in exactly 2–3 sentences. Preserve the key facts — who, what, when, where, why — in clear, neutral language. Do not add opinions or details absent from the article. Article: {{article}}

02 / THREE STRATEGIES

Pick how hard it should think.

S·01

Rewrite

One-shot rewrite through a versioned meta-prompt. Fast enough to feel like autocorrect for prompts.

1 model call · ~2s

S·02

Iterate

A critic names every weakness; a rewriter fixes them. Repeats up to three rounds until quality holds.

critique → rewrite → loop

S·03

Ensemble

Three candidates generated at different temperatures, then ranked pairwise by an impartial judge.

3 candidates · swap-debiased judge

03 / RECEIPTS

A regression suite for prompts.

Don't take its word for it — anyone can claim a prompt got "better." Prismo runs the original and your edit on your real example inputs, judges the outputs blind — both orders, to cancel position bias — and hands you a win rate. Save those inputs as a test-set and re-run it every time you change the prompt or switch models, across Anthropic, OpenAI, and Gemini. If a change quietly regresses, you'll see it before your users do.

Don't take its word for it. Read the receipt.

Every optimization comes with evidence: the original vs. your edit, run on your real inputs and judged blind, both orders — so a win rate is something you can actually trust.

Same receipts whether you bring your own key or run on Prismo's hosted inference — see pricing below.

Shareable receipts — send a "won 5/5 on my inputs" link. No login to view.

04 / SAVE MONEY

Same quality. A fraction of the cost.

An optimized prompt on a cheaper model can often match your original on an expensive one. Prove it with the same win-rate test — then ship the swap and watch the bill drop.

BEFOREOriginal prompt frontier model $$$ per 1k runs

AFTER · SAME WIN RATEOptimized prompt cheaper model ~1/10th the cost

05 / PRICING

Free with your key.
Hosted when you'd rather not.

FREE · BYOK

$0forever

bring your own key · no account

Every feature — optimize, receipts, saved test-sets, cost comparisons
Unlimited runs on your own Anthropic, OpenAI, or Gemini key
Runs in your browser. No install, no card, no login

Open the web app

PREMIUM

$7.99$5.99/mo

hosted, no key · Fast + Balanced models

Prismo's hosted inference — nothing to set up, no key to manage
Fast and Balanced model tiers, every optimization strategy
Shareable result links + a generous fair-use allowance

COMING SOON PRO

$19/mo

hosted · everything in Premium + Quality models

The Quality tier — Opus, GPT-4.1, Gemini 2.5 Pro — plus all of Premium
A bigger monthly fair-use allowance for heavy days
Blind-judged receipts across every model, in one place

Hosted plans include a monthly fair-use allowance — the app shows a meter with how much you have left. Bring-your-own-key is always unlimited, and heavy Quality users can fall back to BYOK anytime, free.

06 / ALSO NATIVE · macOS

Also native on macOS.
A floating panel, one hotkey away.

Prefer a desktop app? The signed, notarized DMG puts Prismo one ⌘⇧P away, anywhere. Same engine — use the free hosted trial, or paste your own Anthropic, OpenAI, or Gemini key in Settings.

requiresmacOS 14 Sonoma+

architectureApple silicon & Intel

hotkey⌘⇧P, everywhere

themesAurora · Prism · Paper

accessibility3 colorblind modes

keysAnthropic · OpenAI · Gemini

signatureDeveloper ID, notarized

07 / PRIVACY

Your prompts are the product.
Just not ours.

Prompts are sent to the Prismo service only to generate a result. Your history and settings stay on your device — in your browser or on your Mac.

never stored · never logged · never sold · never used for training