Tools
* OPAM package repository <http://opam.ocaml.org/packages>
* API reference <https://ocaml.org/api/>

Meta links
* Weekly News <http://alan.petitepomme.net/cwn/index.html>: the highlights of the week via Atom feeds, newsletters or read online
* OCaml Planet <https://ocaml.org/community/planet/> (Blog aggregator)
* Awesome OCaml by rizo <https://github.com/rizo/awesome-ocaml>
* OCamlverse <https://ocamlverse.github.io>

Introductions
* OCaml for the Skeptical <https://www2.lib.uchicago.edu/keith/ocaml-class/home.html>
* What I wish I knew when learning OCaml — Daniil Baturin <https://baturin.org/docs/ocaml-faq/>
* Many things about OCaml <http://typeocaml.com/>

Books
* Functional Programming in OCaml· GitBook <https://www.cs.cornell.edu/courses/cs3110/2019sp/textbook/>
* PLEAC cookbook <http://pleac.sourceforge.net/pleac_ocaml/index.html>. Examples basically.

Syntax
* OCaml has some new shiny syntax | Notes on Computing <https://jobjo.github.io/2019/04/24/ocaml-has-some-new-shiny-syntax.html>. This also mentions application programming.
* Detecting use-cases for GADTs in OCaml | Mads Hartmann <https://mads-hartmann.com/ocaml/2015/01/05/gadt-ocaml.html>

Typing & category theory
* Shayne Fletcher: Polymorphic variants : Subtyping and variance <http://blog.shaynefletcher.org/2017/03/polymorphic-variants-subtyping-and.html>
* Variants pdf <https://www.math.nagoya-u.ac.jp/~garrigue/papers/variants.pdf> academic paper on variants
* +'a and -'a (subtyping) <https://blog.janestreet.com/a-and-a/>

* Seven Sketches in Compositionality:An Invitation to Applied Category Theory <https://arxiv.org/pdf/1803.05316.pdf>

System
* How to wrap C functions <http://www.linux-nantes.org/~fmonnier/OCaml/ocaml-wrapping-c.html>
* Unix system programming <http://ocaml.github.io/ocamlunix/>
* Ocaml Sockets · Brool <http://www.brool.com/post/ocaml-sockets/> (check out for Lwt sockets instead of plain Unix sockets>
* Performance and Profiling <https://ocaml.org/learn/tutorials/performance_and_profiling.html>

Performance
* The Flying Frog Blog: Does reference counting really use less memory than tracing garbage collection? Swift vs OCaml <https://flyingfrogblog.blogspot.com/2017/12/does-reference-counting-really-use-less.html?m=1>