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PromptEval
What it is
PromptEval is a web and API service for evaluating and improving prompts for large language models. It assigns a reproducible score from 0 to 100, with diagnostics for clarity, specificity, structure, and robustness. Its analysis flags problems, warnings, and strengths, then offers focused recommendations. A token optimizer can shorten prompts while preserving intent and reports the percentage reduction. A versioned library records prompt versions, score history, and differences. The A/B Playground compares two prompts across up to seven criteria and displays radar-chart results; it uses an API key supplied by the user. An official GitHub Action can fail a pull request when a score drops, a contradiction appears, or a prompt regresses against production. Pro and Team users can serve a production prompt by slug through an API endpoint, with changes taking effect in about 60 seconds. The Free plan is billed forever and includes three web evaluations per month, 10 API lint calls, up to five library prompts, and an 8,000-character limit. Basic costs $9 a month; Pro costs $19 a month. API quotas vary by plan, with a five-requests-per-minute limit.
For and against
For
- Scores prompts across four diagnostic dimensions.
- Keeps versions, scores, and diffs.
- GitHub Action can flag prompt regressions.
- BYOK inference consumes no managed quota.
- Prompts are discarded after evaluation.
Against
- Free plan allows three web evaluations monthly.
- API is limited to five requests per minute.
- Free prompt limit is 8,000 characters.
- Team pricing is custom.
The verdict
PromptEval combines prompt scoring, revision support, version history, and production-focused checks in a web and API service. The free plan has defined usage and character limits, while paid plans begin at $9 a month.
Who it suits
PromptEval is aimed at solo developers, developers using AI at work, and teams maintaining prompts in production. Its API, version history, and pull-request checks may suit workflows that include prompt evaluation and review.
Plans and prices
Free
3 web evals/month · API lint 10/month · library up to 5 prompts · prompts up to 8,000 characters
Read 30 Sep 2026 · prompt-eval.com
Basic
30 credits/month · API lint 30/month · prompts up to 12,000 characters
Read 30 Sep 2026 · prompt-eval.com
Pro
Unlimited web usage · API lint 75/month · prompts up to 35,000 characters
Read 30 Sep 2026 · prompt-eval.com
Team
API lint 250/month · prompts up to 60,000 characters · priority support within 24h
Read 30 Sep 2026 · prompt-eval.com
On the record
- A/B testing
- The A/B Playground tests two prompts with a user-provided API key across up to seven criteria and displays radar-chart results.prompt-eval.com · read 30 Sep 2026
- API limits
- The Eval API has managed monthly quotas of 10, 30, 75, and 250 calls for Free, Basic, Pro, and Team, respectively, with a 5-requests-per-minute rate limit.prompt-eval.com · read 30 Sep 2026
- BYOK
- An Anthropic key supplied through X-Provider-Key runs inference on the user's key, consumes no managed quota, and unlocks full mode on every plan.prompt-eval.com · read 30 Sep 2026
- CI integration
- The official GitHub Action can fail a pull request when a score drops, a contradiction appears, or a prompt regresses against production.prompt-eval.com · read 30 Sep 2026
- Optimization
- The token optimizer compresses prompts while preserving intent and reports the percentage reduction.prompt-eval.com · read 30 Sep 2026
- Privacy and security
- PromptEval says prompts are discarded after evaluation, never used to train AI models, protected by Row Level Security, and transmitted over HTTPS.prompt-eval.com · read 30 Sep 2026
- Production serving
- Pro and Team users can serve a production prompt by slug through GET /api/v1/prompts/{slug} without redeploying, with changes taking effect in about 60 seconds.prompt-eval.com · read 30 Sep 2026
- Product purpose
- PromptEval evaluates and optimizes prompts for large language models as a SaaS platform.prompt-eval.com · read 30 Sep 2026
- Prompt analysis
- The evaluator returns critical issues, warnings, strengths, and surgical recommendations for prompt improvements.prompt-eval.com · read 30 Sep 2026
- Scoring
- It provides a reproducible 0–100 score with diagnostics across clarity, specificity, structure, and robustness.prompt-eval.com · read 30 Sep 2026
- Support
- The Team plan includes priority support with a stated 24-hour response target.prompt-eval.com · read 30 Sep 2026
- Target users
- The product is positioned for solo developers, developers using AI at work, developers shipping prompts to production, and teams governing production prompts.prompt-eval.com · read 30 Sep 2026
- Versioning
- The versioned library stores prompt versions with score history and diffs.prompt-eval.com · read 30 Sep 2026
