Prev Next

Erlang / Erlang Basics Interview questions

Describe the "let it crash" philosophy?

"Let it crash" means Erlang code generally doesn't try to defensively handle every possible failure inline. Instead, when a process hits an unexpected state, it's allowed to terminate, and a supervisor detects that exit and restarts it fresh.

The reasoning: trying to anticipate and recover from every edge case inline bloats code and often masks bugs by leaving the process in a half-corrupted state. Restarting from a clean init/1 is usually safer and simpler than trying to patch a process back to a known-good state after something goes wrong.

This doesn't mean errors are ignored — it means error handling is separated from business logic and pushed up to a supervisor, which is exactly what supervision trees are designed for. It's why gen_server callbacks are often written for the "happy path" and let genuinely exceptional input simply crash the process.

What is the main idea behind 'let it crash'?
Why is restarting a crashed process often preferred over patching its state in place?

Invest now in Acorns!!! 🚀 Join Acorns and get your $5 bonus!
Acorns Logo

Invest now in Acorns!!! 🚀
Join Acorns and get your $5 bonus!

Earn passively and while sleeping

Acorns is a micro-investing app that automatically invests your "spare change" from daily purchases into diversified, expert-built portfolios of ETFs. It is designed for beginners, allowing you to start investing with as little as $5. The service automates saving and investing. Disclosure: I may receive a referral bonus.

Robinhood Logo

Invest now!!! Get Free equity stock (US, UK only)!

Use Robinhood app to invest in stocks. It is safe and secure. Use the Referral link to claim your free stock when you sign up!.

The Robinhood app makes it easy to trade stocks, crypto and more.


Webull Logo

Webull! Receive free stock by signing up using the link: Webull signup.

More Related questions...

What is Erlang? What is the BEAM virtual machine? What are processes in Erlang? What is the actor model in Erlang? What are atoms in Erlang? What are tuples in Erlang? What are lists in Erlang? What is pattern matching in Erlang? Define immutability in Erlang? What is a PID? What is a module in Erlang? What are guards used for in Erlang? What is OTP? What is a gen_server? What is a supervisor? Describe the "let it crash" philosophy? What are records in Erlang? What is message passing? What is hot code loading? What are binaries/bitstrings in Erlang? What is ETS? What is Mnesia? What are list comprehensions? What is a behavior in Erlang? What are ports in Erlang? What is a NIF (Native Implemented Function)? How do you spawn a process in Erlang? How does Erlang achieve concurrency without shared memory? What is the difference between spawn and spawn_link? What is the difference between a list and a tuple? Why is Erlang considered fault-tolerant? How does pattern matching differ from equality comparison? When should you use ETS instead of process state? How do you handle errors in Erlang without try/catch? Why doesn't Erlang have mutable variables? What is the difference between gen_server and gen_statem? How do you implement a simple supervision tree? What happens when a linked process crashes? When would you choose Mnesia over ETS? How do you use the observer tool to inspect a running system? Explain the execution flow of a gen_server call? Explain the internal working of the BEAM scheduler? How can you optimize message passing between heavy processes? Explain the lifecycle of a supervised process? How do you troubleshoot process mailbox overflow? What is the difference between synchronous and asynchronous message passing in OTP? Which is better for state management, ETS or process dictionaries, and why? How does distributed Erlang handle node failures?
Show more question and Answers...

#

Comments & Discussions