Workflow input
Rewrite onboarding copy
Improve this onboarding message for clarity, confidence, and conversion while keeping the tone direct.
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.
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
Model output A
Direct answer with concise structure and moderate cost.
Model output B
Better structure, stronger instructions, and cheaper total spend.
Product in action
See what works before you commit.
Compare outputs side-by-side
See cost before committing
Pick the best result instantly
Inside the product
See real workflow decisions, not abstract AI promises.
Product screenshot
Compare outputs across models
Line up the same workflow against multiple models.
Spot differences in structure, cost, and completeness immediately.
Keep the strongest result moving forward.
Output A
Clear structure, lower cost, concise recommendation.
Output B
Stronger structure, better format, and higher completion quality.
Recommendation view
Pick the best result with confidence
Highlight the strongest result across prompt and model combinations.
Surface confidence and cost signals in one place.
Choose faster without second-guessing the output.
Recommended Result
GPT-4.1 mini on Variant 2
High confidence: stronger structure and lower cost.
Tokens 396Cost $0.0002
Optimize flow
Improve prompts automatically
Generate tighter, more structured, and more explicit variants.
Test them across your selected models.
Promote the best prompt back into the workflow instantly.
Original
Baseline prompt with broad instructions.
Variant 1
Shorter version with clearer constraints.
Optimized
More structured, clearer instructions, and best overall score.
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