01
LANGUAGE PATH
Ready nowTake one language all the way to a project
Elixir and Erlang stay separate across Scratch, Foundation, Intermediate, and Project. Finish Foundation in either language to enter the BEAM mainline.
Erlang and Elixir both run on the BEAM
Learn by doingErlang+Elixir
Start with values, types, and functions. Once the syntax feels familiar, see how processes work together.Elixir and Erlang each have their own beginner path. Pick one. You do not need to learn both at once.
FROM SCRATCHElixir from scratch31 lessons · four stages · syntax to projectFROM SCRATCHErlang from scratch31 lessons · four stages · terms to projectI know the basicsEnter the BEAM path7 core stations · bilingual work is an extension
2beginner paths
62language lessons
7BEAM core stations
2 / 2reviews / bilingual extensions
BEAM RUNTIME
VMBEAMprocess · mailbox
scheduler · isolation
scheduler · isolation
01ElixirGenServer
02Erlanggen_server
03OTPSupervisor
S1
S2
S3
Four connected steps
Learn the language. Then read a real system.
The language paths teach code, tests, and project tools. The BEAM path deals with concurrency, failure, and recovery. After the capstone, Case Chat shows those choices inside a working voice service.
02
BEAM PATH
BEAM mainlineSolve concurrent-system problems
Each station starts with a failure: mismatched replies, mailbox growth, restart scope, or exhausted capacity. Switch the code between Elixir and Erlang.
03
CAPSTONE
Mainline finishShip a reliable task system
Combine a bounded queue, supervision, idempotency, retry, and node loss in one project. Prove it with failure experiments.
04
CASE STUDY
Chinese case studyCase Chat: trace a voice service
Follow one voice session through a real project, then read Mix, supervision, WebSockets, recorder processes, and browser code in context. The case study is currently written in Chinese.
Quick links
Open the learning toolboxUseful references, close at hand
Elixir DocsLook up Elixir syntax and the standard library.↗Elixir InstallFollow the official installation steps for your operating system.↗Erlang DocsLearn how Erlang/OTP works and how to use it.↗OTP DownloadsDownload Erlang/OTP and read the release notes.↗hex.pmFind Elixir and Erlang packages and their versions.↗Elixir ForumSearch for answers and discuss Elixir questions.↗
How to learn
Guess first. Then run the code.
Every lesson has code you can change. If the output surprises you, read it, then change one thing. That makes the cause easier to find.
01
Run code first
A short example in every lessonEvery new idea comes with a small example for IEx or erl. The page also shows messages moving between processes.
02
See both forms
One task, two languagesSolve the same problem in Elixir and Erlang. The syntax differs, but both run on the BEAM.
03
Change one thing
49 small challengesAnswer a question, translate a snippet, or change one condition. A wrong answer is still useful: it tells you what to try next.
04
Let it break
Safe failure experimentsDelay a reply, fill a mailbox, or stop a process. Watch what happens—and notice what the experiment cannot prove.
Where the paths meet
Different syntax. Shared bones.
Once you know one language, you do not need to relearn everything. Spot the same values, patterns, and functions, then see how both use BEAM processes and messages.
- 1Use the familiar language as a ruler
Start with the data and functions you already understand.
- 2Compare the other spelling
Find the same atoms, tuples, patterns, and modules.
- 3Share the runtime skills
Learn processes, messages, and supervision together.
ELIXIR
ONE VMERLANG
:okthe same atom labelokFoo.bar()the same module underneath'Elixir.Foo':bar():lists.reverse(xs)the same Erlang toollists:reverse(Xs)fn x -> x * 2 endboth create an anonymous functionfun(X) -> X * 2 endGenServerthe same OTP behaviourgen_serverProblem-driven · BEAM mainline
From one concrete failure to a reliable system
The core has 7 stations, plus 2 placement reviews and 2 bilingual extensions. Finish processes, OTP, capacity, and the capstone in your familiar language. Add shared terms and adapters when you need interoperability.
Core progress · setup, reviews, and bilingual extensions excluded0 / 7 core stations
0%
01
Get ready and meet the BEAM
Check the tools, then use a first process to separate functions, state ownership, PIDs, and messages.
00
SetupErlangElixirMix
Set up your tools
[Prerequisite diagnostic] Why can this computer not find Erlang, Elixir, or Mix: is a tool missing, are the versions incompatible, or is PATH stale?
01
SetupBEAMElixirErlang
The starting line
[Prerequisite diagnostic] When mix test fails, how can you first tell whether the problem belongs to the command, project directory, runtime, or code?
02
BEAMOTP
Processes and mailboxes
When several senders update a counter at once, who owns the state, and how can we spot messages that the mailbox never handles?
02
Add a language when needed
Review the other language only when you need it. A single-language learner can keep moving.
R1
Optional reviewElixir
An Elixir data pipeline
[Optional language review] How can we split a log cleaner that meets blank lines, unknown levels, and malformed input into independently testable stages?
R2
Optional reviewErlang
Read Erlang
[Optional language review] How can we rebuild the same log tool in Erlang and make both implementations obey one input-output contract?
03
Handle concurrency failures
Enter OTP through late replies, mailbox growth, restart scope, and capacity limits.
03
ElixirErlangBEAM
Messages and timeouts
When concurrent replies can be late or out of order and the service process can exit, how do we make sure each caller gets its own result?
04
ElixirErlangOTP
OTP rules for messages
After replacing a hand-written loop with GenServer, how should call and cast be divided, and how can slow work be kept from filling the mailbox?
05
ElixirErlangOTP
A supervision tree that restarts
When Registry, a worker supervisor, and a dispatcher depend on one another, which restart strategy recovers enough without restarting too much?
06
ElixirErlangBEAM
Put a limit on concurrency
When ten thousand URL checks arrive in a burst, how do we limit running and waiting work while returning timeout, failure, or busy clearly?
04
Protect system boundaries
The core runs from node loss to the capstone. Take the shared-term and adapter branch only when two languages must work together.
07
BEAMOTP
When a BEAM node disappears
If a remote worker disconnects midway through a request, what result does the caller get, and how does the system mark stale data, retry, and avoid duplicate execution?
X1
Bilingual extensionElixirErlangBEAM
Agree on shared BEAM terms
When an order receives pay, ship, cancel, and duplicate events, how can Elixir and Erlang follow the same state-machine protocol?
X2
Bilingual extensionElixirErlang
Two-language partners
Between an Elixir API and an Erlang worker, how do we fix the text, data-shape, and error protocol so record or Unicode changes do not spread?
08
ElixirErlangOTP
A reliable job runner
How do we keep capacity and retries bounded through queue-full, worker exit, timeout, and node loss—and state honestly what is still missing across a full VM restart?
Try it for 3 minutes
Send a message. Wait for a reply.
Every process has a mailbox. Send a few messages, then handle them one by one. Turn on “drop reply” to see what happens when work is handled but no answer comes back.
- 01Sending a message does not mean it was received or handled
- 02A timeout ends the wait; it does not recall the message
- 03A mailbox can pile up if work arrives faster than it is handled
PROCESS 01clientsends requests
PROCESS 02serverHandled 0
The mailbox is emptyreply: normal
Event logNewest first
01Waiting for the client to send a message
This browser model shows how messages move. It is not a real Erlang VM. Use it to watch messages queue up and receive replies. The lesson pages also include code you can run in IEx or erl.
Station 08 · Capstone
Build a task scheduler
Build the core in either Elixir or Erlang: bound the queue, name each failure outcome, and cap retries. Add the other language only after the interoperability lessons.
See the requirementsAPPLICATION APIvalidate · normalize · reply
SCHEDULER COREqueue · dispatch · retry
worker 01
worker 02
worker 03
SUPERVISORexit → observe → recover
Learning toolbox
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Tutorials and Courses2 resources
Packages and Tools4 resources
Community2 resources
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