For python, I use hippie-expand mostly, but https://www.masteringemacs.org/article/jedi-completion-library-python https://www.masteringemacs.org/article/jedi-co

For python, I use hippie-expand mostly, but https://www.masteringemacs.org/article/jedi-completion-library-python https://www.masteringemacs.org/article/jedi-completion-libra... does good auto-completion. Flycheck handles syntax issues for many languages, including Python. https://github.com/flycheck/flycheck https://github.com/flycheck/flycheck For javascript, I use js2-mode for syntax highlighting. I haven't ever tried js3-mode, but I understand it does better indentation. ac-js2 does autocomplete for js2-mode. You can throw in web-beautify as well - https://github.com/yasuyk/web-beautify https://github.com/yasuyk/web-beautify For many languages, I use yasnippet as well. Yasnippet rocks.