PromptOS

Run, compare, and optimize AI workflows.

Stop guessing which prompt or model works best. PromptOS lets you test, compare, and choose the best result — instantly.

Try it free View pricing

Prompt AGPT-4.1Claude

Workflow input

Rewrite onboarding copy

Improve this onboarding message for clarity, confidence, and conversion while keeping the tone direct.

Best result

Recommended: GPT-4.1 mini

Stronger structure, lower cost, and clearer instructions than the alternatives.

Tokens 418Cost $0.0003

The problem

Most AI tools give you one answer.

You don’t know:

+if it’s the best

+if it’s the cheapest

+if another model would perform better

The solution

PromptOS shows you the best result — not just one result.

run prompts across models

compare outputs and cost

generate improved variants

choose with confidence

Inside the product

See real workflow decisions, not abstract AI promises.

Compare outputs across models

Run the same prompt across multiple models and see quality, cost, and speed side by side.

Compare output quality instantly

See token usage and estimated cost

Choose the model that fits the job

PromptOS

Experiment

Marketing Email

3 models

GPT-4.1

Strong personalization and clear CTA.

Hi Sarah — I noticed your team is hiring outbound reps...

512 tokens$0.00182.1s

Claude 3.5 Sonnet

Best balance of clarity, tone, and cost.

Recommended

Hi Sarah — reaching out because PromptOS helps growth teams compare...

438 tokens$0.00111.8s

Gemini 1.5 Pro

Faster answer, but weaker structure.

Hello Sarah, I wanted to share a quick note about using AI...

401 tokens$0.00141.4s

Pick the best result with confidence

PromptOS scores and recommends the strongest output based on quality, clarity, cost, and structure.

Transparent scoring

Recommendation reasons

Cost-aware decisions

Claude 3.5 Sonnet on Variant 2

92/100Recommended

Most comprehensiveClear structureActionable and specificLowest cost

Here’s the strongest result: a structured response with a sharp summary, concrete next steps, and a format the team can reuse.

396 tokens$0.00021.7s

Improve prompts automatically

Generate stronger prompt variants, test them, and keep the version that performs best.

Instant prompt variants

Better outputs with less effort

Save your best prompts

Original prompt

Write an onboarding email for new users of our analytics product.

Original62/100

Variant 1

78/100

Shorter prompt with sharper constraints.

Variant 2

Recommended

More structured instructions with the best score.

85/100Best variant

Variant 3

74/100

More explicit tone, but less concise.

Best variant

Draft a welcome email with a clear subject line, 3 product benefits, one setup step, and a direct CTA to create the first dashboard.

How it works

Three steps to better AI decisions

Write your prompt

Run it across models

Choose the best result

Why teams use it

Outcomes, not guesswork.

Choose the best model with confidence

Reduce AI cost by testing before committing

Get better outputs without trial and error

Improve prompts automatically

Developers, founders, and teams who use AI daily

Pricing

Choose the path that fits how you work.

Free

Try PromptOS with 1 run

BYOK

Use your own OpenAI or Anthropic account

Pro

$9/month — no setup required. We handle models, billing, and optimization

PromptOS is built for teams who need a repeatable system for AI workflows, not one-off prompt guessing.

Get started

Run better AI workflows with confidence.

Try it free