Fix MicroPython “MemoryError: memory allocation failed”

What you see

Traceback (most recent call last):
  File "main.py", line 38, in <module>
  File "main.py", line 22, in read_page
MemoryError: memory allocation failed, allocating 4096 bytes

Traceback (most recent call last):
  File "main.py", line 38, in <module>
  File "main.py", line 22, in read_page
MemoryError: memory allocation failed, allocating 4096 bytes

Quick fix — try in order

1. 1

   Check free memory

   import gc; gc.collect(); print(gc.mem_free()) shows what is left. Print it in your loop to spot leaks.

   Tried it
2. 2

   Call gc.collect() regularly

   Especially after network requests or building large strings.

   Tried it
3. 3

   Avoid building big strings

   Joining strings in a loop creates many temporary copies. Write pieces directly or use a pre-allocated bytearray.

   Tried it
4. 4

   Read network responses in chunks

   Do not hold a whole web page in memory; stream and parse it piece by piece.

   Tried it
5. 5

   Precompile large modules to .mpy

   Compiling .py files with mpy-cross saves the RAM the board would use to compile them on import.

   Tried it

Why it happens