PromptEval

Free plan APIWeb

What PromptEval is

PromptEval is a web and API service for evaluating and optimizing prompts for large language models. It produces a reproducible score from 0 to 100, with diagnostics for clarity, specificity, structure, and robustness. Its analysis flags issues, warnings, and strengths, and offers recommendations; a token optimizer compresses prompts while preserving intent and reports the reduction percentage. A versioned library stores prompt revisions with score history and diffs. The A/B Playground compares two prompts across up to seven criteria, using a user-provided API key and radar-chart results. Its GitHub Action can fail a pull request for a lower score, a contradiction, or a regression against production. Pro and Team users can serve production prompts by slug through an API endpoint; updates take effect in about 60 seconds. The Free plan costs nothing and allows three web evaluations and 10 API lint calls per month, five library prompts, and prompts up to 8,000 characters. Basic costs $9 a month; Pro costs $19 a month; Team pricing is custom. API quotas vary by plan and the rate limit is five requests per minute.

Who it suits

PromptEval suits solo developers and teams evaluating prompts, including developers shipping prompts to production or governing them across a team. The API, GitHub Action, and versioned library support prompt workflows beyond one-off evaluation.

What it does well

Reproducible scoring includes four diagnostic areas.
Token optimizer reports prompt reduction percentage.
Versioned library stores score history and diffs.
GitHub Action can flag prompt regressions in pull requests.
BYOK can unlock full mode on every plan.

What to know first

Free plan allows three web evaluations monthly.
API has a five-requests-per-minute rate limit.
Team pricing is custom.
Free prompts are limited to 8,000 characters.

Limits

The free plan includes three web evaluations and 10 API lint calls per month, supports a library of up to five prompts, and accepts prompts up to 8,000 characters. Managed API quotas are 10, 30, 75, and 250 calls monthly for Free, Basic, Pro, and Team, respectively; all have a five-requests-per-minute rate limit.

Plans

Plan	Billed and limits	Price
Free	forever · 3 web evals/month · API lint 10/month · library up to 5 prompts · prompts up to 8,000 characters	Free
Pro	$19/month · Unlimited web usage · API lint 75/month · prompts up to 35,000 characters	$19 a month
Basic	$9/month · 30 credits/month · API lint 30/month · prompts up to 12,000 characters	$9 a month
Team	Custom · API lint 250/month · prompts up to 60,000 characters · priority support within 24h	On request

As prompt-eval.com lists them, read 30 Sept 2026. The maker's own page has the final word.

Getting started

Open prompt-eval.com.
Choose the free plan or a paid plan.
Use the web platform or API to evaluate prompts.
Supply an Anthropic key through X-Provider-Key to run inference on your key without using managed quota.

Verdict

PromptEval combines prompt scoring, optimization, version history, and testing with API and pull-request workflows. Review the plan quotas, character limits, and rate limit before choosing a tier.

Questions

Is there a free plan?

Yes. Free includes three web evaluations per month, 10 API lint calls monthly, a library of up to five prompts, and an 8,000-character prompt limit.

What do the plans cost?

Free costs nothing, billed forever. Basic is $9 a month and Pro is $19 a month; Team is custom-priced.

Which platforms does PromptEval support?

PromptEval is available on web and through an API.

Can it compare prompts?

Yes. The A/B Playground compares two prompts across up to seven criteria and displays radar-chart results using a user-provided API key.

Does it integrate with GitHub?

It offers an official GitHub Action that can fail a pull request for a score drop, a contradiction, or regression against production.

How does PromptEval handle prompts and privacy?

PromptEval says prompts are discarded after evaluation, are not used to train AI models, are protected by Row Level Security, and are transmitted over HTTPS.

Facts from PromptEval's own pages

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, 30 Sept 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, 30 Sept 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, 30 Sept 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, 30 Sept 2026
Optimization: The token optimizer compresses prompts while preserving intent and reports the percentage reduction. · prompt-eval.com, 30 Sept 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, 30 Sept 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, 30 Sept 2026
Product purpose: PromptEval evaluates and optimizes prompts for large language models as a SaaS platform. · prompt-eval.com, 30 Sept 2026
Prompt analysis: The evaluator returns critical issues, warnings, strengths, and surgical recommendations for prompt improvements. · prompt-eval.com, 30 Sept 2026
Scoring: It provides a reproducible 0–100 score with diagnostics across clarity, specificity, structure, and robustness. · prompt-eval.com, 30 Sept 2026
Support: The Team plan includes priority support with a stated 24-hour response target. · prompt-eval.com, 30 Sept 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, 30 Sept 2026
Versioning: The versioned library stores prompt versions with score history and diffs. · prompt-eval.com, 30 Sept 2026

Where PromptEval stands on Freedom251

AI Prompt Generators#9 of 28