Weekend Projects Easy 5,400/mo

Password Strength Checker API

API that scores password strength and suggests improvements. Check if passwords are strong, breached, or common — with actionable improvement suggestions.

SecurityAPI
MRR Potential
$2K–$8K
Time to MVP
1 weekend
Search Volume
5,400/mo
Market Size
$300M

The Problem

Password strength meters are inconsistent — 'Password1!' passes most checks but is terrible. Built-in browser password checks are basic. No API checks passwords against breach databases AND provides strength scoring. Password policy enforcement requires custom code. Users create weak passwords because feedback is poor.

The Solution

Password strength API that scores passwords on entropy, checks against breach databases (Have I Been Pwned), identifies common patterns, and suggests specific improvements — without ever storing the password.

Target Audience

Developers building signup forms with password validation, security teams enforcing password policies, and SaaS platforms wanting better password UX

Key Features

1
Strength scoring 0-100 based on entropy, length, and pattern analysis
2
Breach checking against Have I Been Pwned database using k-anonymity
3
Common pattern detection: keyboard walks, dates, names, dictionary words
4
Improvement suggestions telling users exactly how to make it stronger
5
Embeddable widget for signup forms with real-time feedback
6
Zero-knowledge: passwords are never stored or logged

Market Opportunity

Market Size
$300M — Authentication and security tools
Monthly Searches
5,400/mo
MRR Potential
$2K–$8K
Why Now?

Data breaches make password security critical. NIST guidelines changed password recommendations. Credential stuffing attacks are increasing. Better UX reduces support tickets. Zero-knowledge APIs build trust.

Revenue Model

Free: 1K checks/day. Pro: $5/mo (10K/day + widget). Business: $15/mo (100K/day + custom policies). Annual: 20% discount.

Competitive Landscape

zxcvbn (Dropbox)

Open-source library. Good scoring, no breach checking, no API

Have I Been Pwned API

Breach checking only. No strength scoring, no suggestions

Built-in browser checks

Basic, inconsistent across browsers, no breach data

Custom validation regex

Weak security, no entropy scoring, false sense of security

Recommended Tech Stack

Next.jsNode.jsHIBP k-anonymity APIzxcvbnVercel EdgeStripe

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