About Lemmerly

Lemmerly is a self-calibrating vocabulary engine. It uses an ELO rating system — the same mathematical model used to rank chess players — to measure and track your vocabulary across 70,000+ English words.

Every session, you answer four-choice questions. Words you know move up in difficulty. Words you miss are scheduled for review. Over time, Lemmerly builds a precise picture of your vocabulary range and assigns you a rating — your vocabulary ELO.

Eight titles mark your progress: from Initiate at 800 ELO to Lex Archmasterat 2300 ELO. Most university graduates land between 1200 and 1500.

Vocabulary is one of the strongest predictors of reading comprehension, academic performance, and professional success. Yet most vocabulary tools are either too simple (flashcard apps) or too narrow (GRE word lists).

Lemmerly takes a different approach: treat vocabulary like a skill with a measurable rating, not a checklist of words to memorise. The ELO system means every question tells us something — both about the word and about you.

We also rated 29,875 books from Project Gutenberg using the same system. Now we can tell you exactly which books match your current level — and which ones to aim for next.

Lemmerly was built by Manu Lauria, an independent developer based in India. The project began in early 2026 as an experiment in applying competitive rating systems to language learning.

The vocabulary corpus was built from multiple sources including WordNet, Project Gutenberg, Wikipedia, and Webster's 1913 dictionary — processed and rated using a combination of local and cloud language models over several months.

Lemmerly launched on March 24, 2026.

Lemmerly uses Google OAuth solely for authentication — to let you sign in without creating a separate username and password.

When you sign in with Google, we receive only:

• Your name — displayed on your profile
• Your email address — used to identify your account
• Your Google profile ID — used for secure authentication

We do not access your Gmail, Google Drive, Google Contacts, Google Calendar, or any other Google service. We request the minimum scopes required: openid, email, and profile.

Your Google credentials are never stored by Lemmerly. Authentication is managed by Supabase Auth, an open-source authentication platform.

Lemmerly is built with:

• Next.js 14 — web application framework
• Supabase — database and authentication (PostgreSQL, Seoul region)
• Vercel — hosting and deployment
• Razorpay — payment processing (India)

The vocabulary database contains 70,000+ words, each with an ELO rating derived from its frequency, difficulty, and user performance data.

For questions, feedback, or support: