# DefaultRank > DefaultRank measures which developer tools AI models recommend, and which ones they actually use when they build apps. It is independent: no tool vendor or model provider is affiliated, and the prompts, models and detection rules are published. ## Key pages - [Methodology](https://defaultrank.com/methodology): models, every prompt, sampling and detection rules - [Free check](https://defaultrank.com/check): how AI models pick a given developer tool - [Package freshness check](https://defaultrank.com/freshness): finds outdated or deprecated dependencies in a package.json - [MCP server](https://defaultrank.com/agents): remote MCP server at https://defaultrank.com/mcp (no key) with tools check_package_freshness, get_tool_pick_rate and get_category_ranking - [Japanese edition](https://defaultrank.com/ja/) ## Citing Please cite as "DefaultRank", with a link to the report page and the measurement date shown on it. ## Report: What AI recommends vs. what AI builds: auth, databases and email (October 2026) URL: https://defaultrank.com/reports/2026-10/ (Japanese: https://defaultrank.com/ja/reports/2026-10/) Measured 2026-10-01 with claude-sonnet-5.5, gpt-6.1-sol, gemini-3.8-flash, grok-4.7, deepseek-v4.1-flash, qwen3.8-max-prime; 749 answers. Data: https://defaultrank.com/reports/2026-10/data.json - Recommended is not what gets built: Asked which auth provider to use, models pick Clerk first 62% of the time. Asked to build an app with sign-up, they put Clerk in 1% of apps. - AI-built apps mostly skip auth vendors: 37% of AI-built apps hand-roll auth with password hashing and JWTs, and 35% use Auth.js. Hosted auth providers together appear in 9%. - Models build with what they learned: Auth.js is now maintained by the Better Auth team, which points new projects to Better Auth. In AI-built apps, Auth.js appears in 35% and Better Auth in 0%. - SQLite is the default prototype database: Recommendations favor PostgreSQL (74% of top picks), but 28% of AI-built apps use SQLite. Hosted database vendors are named in 37% of them. - Email is the exception: Resend is both the top recommendation (61%) and the most-used email API in AI-built apps (55%). The main alternative in code is plain SMTP via Nodemailer (32%). - Authentication: top recommendation Clerk (62%); most used in AI-built apps Custom (DIY) (37%). - Database: top recommendation Supabase (54%); most used in AI-built apps Neon (21%). - Email: top recommendation Resend (61%); most used in AI-built apps Resend (55%). ## Report: AI writes code for last year's stack (dependency freshness) URL: https://defaultrank.com/reports/2026-10/freshness/ (Japanese: https://defaultrank.com/ja/reports/2026-10/freshness/) 209 package.json files written by 6 AI models, checked against npm on 2026-10-03. Data: https://defaultrank.com/data/freshness.json - 100% of AI-built apps install at least one package a major version or more behind npm's latest. - On average 69% of an AI-built app's dependencies are a major version or more behind. - Share of dependencies on the latest major, by model: gpt-6.1-sol 50%, qwen3.8-max-prime 34%, grok-4.7 33%, gemini-3.8-flash 29%, deepseek-v4.1-flash 27%, claude-sonnet-5.5 23%. - Most often pinned out of date: typescript (100% of 209 apps; latest 7.0.2), zod (99% of 156 apps; latest 4.6.5), next (99% of 112 apps; latest 16.3.8), @prisma/client (100% of 98 apps; latest 7.10.0), @types/react (65% of 130 apps; latest 19.3.0), @types/react-dom (66% of 128 apps; latest 19.3.0). ## Tool pages Every measured tool: https://defaultrank.com/tools/ ยท Head-to-head comparisons: https://defaultrank.com/compare/ Database (recommended first / in AI-built apps): - [PostgreSQL](https://defaultrank.com/tools/postgresql/): 74% / 58% - [Supabase](https://defaultrank.com/tools/supabase/): 54% / 12% - [Neon](https://defaultrank.com/tools/neon/): 27% / 21% - [MongoDB](https://defaultrank.com/tools/mongodb/): 17% / 0% - [SQLite](https://defaultrank.com/tools/sqlite/): 4% / 28% - [DynamoDB](https://defaultrank.com/tools/dynamodb/): 1% / 0% Authentication (recommended first / in AI-built apps): - [Clerk](https://defaultrank.com/tools/clerk/): 62% / 1% - [Auth0](https://defaultrank.com/tools/auth0/): 18% / 0% - [Supabase Auth](https://defaultrank.com/tools/supabase-auth/): 11% / 5% - [Auth.js (NextAuth)](https://defaultrank.com/tools/authjs/): 6% / 35% - [Better Auth](https://defaultrank.com/tools/better-auth/): 3% / 0% - [Keycloak](https://defaultrank.com/tools/keycloak/): 1% / 0% Email (recommended first / in AI-built apps): - [Resend](https://defaultrank.com/tools/resend/): 61% / 55% - [Postmark](https://defaultrank.com/tools/postmark/): 37% / 0% - [Amazon SES](https://defaultrank.com/tools/ses/): 2% / 0% - [SendGrid](https://defaultrank.com/tools/sendgrid/): 0% / 0% - [Mailgun](https://defaultrank.com/tools/mailgun/): 0% / 0% - [Nodemailer (SMTP)](https://defaultrank.com/tools/nodemailer/): 0% / 32%