Stop fighting Runtime.ImportModuleError, invalid ELF headers, and Mac-built numpy wheels. Paste requirements.txt and get an Amazon Linux compatible layer zip for AWS Lambda. Python 3.10 through 3.14.
Configure your Lambda runtime, then paste requirements.txt
Must match your function's runtime and architecture exactly
No Docker required
Builds in the cloud
Correct architecture
x86_64 or arm64 Graviton
Ready to deploy
python/lib/…/site-packages zip
Perfect for native binary dependencies like numpy, pandas, cryptography, pydantic, scipy. Supports Python 3.10-3.14 on x86_64 and arm64 Graviton.
Developers copy-paste these exact Lambda layer errors into Google every day. Lambda Layer Gen builds Amazon Linux compatible Python layers for numpy, pandas, cryptography, pydantic, scipy, and more. Paste requirements.txt, download a working zip, attach it, and deploy.
Runtime.ImportModuleError: Unable to import module 'lambda_function': No module named 'requests'
Why it happens: Dependencies are missing from your deployment package, or your layer zip uses the wrong folder structure.
Lambda Layer Gen fix: Lambda Layer Gen builds a correctly structured python/ layer zip with your requirements.txt packages pre-installed.
Runtime.ImportModuleError: Unable to import module 'lambda_function': No module named 'pandas'
Why it happens: Pure pip installs on your laptop do not end up on Lambda unless packaged into a layer or deployment zip.
Lambda Layer Gen fix: Paste your requirements.txt and get a layer built for your exact Python runtime. No manual zip wrangling.
Unable to import module 'lambda_function': /var/task/numpy/core/multiarray.so: invalid ELF header
Why it happens: NumPy was compiled for macOS or Windows. Lambda runs Amazon Linux, so the binary format does not match.
Lambda Layer Gen fix: We compile native extensions (numpy, pandas, scipy, pillow) for manylinux2014_x86_64 or aarch64, not your local machine.
invalid ELF header
Why it happens: Classic sign you built a layer on an M1/M2/M3 Mac or Windows PC and uploaded it to Lambda without cross-compiling.
Lambda Layer Gen fix: Lambda Layer Gen resolves invalid ELF header errors by building on the correct Amazon Linux architecture every time.
Importing the numpy C-extensions failed. No module named 'numpy.core._multiarray_umath'
Why it happens: The numpy wheel in your layer targets the wrong Python version or CPU architecture (x86_64 vs arm64 Graviton).
Lambda Layer Gen fix: Specify your runtime and architecture. We match Python 3.10-3.14 and x86_64 or arm64 so C extensions actually load.
OSError: /opt/python/lib/python3.11/site-packages/psycopg2/_psycopg.cpython-311-x86_64-linux-gnu.so: cannot open shared object file
Why it happens: psycopg2, cryptography, lxml, and other packages ship compiled .so files that must match Lambda's OS and glibc.
Lambda Layer Gen fix: Skip Docker and EC2 workarounds. Get a pre-built layer zip with Linux-compatible binaries.
Unable to import module 'lambda_function': No module named 'pydantic_core._pydantic_core'
Why it happens: Pydantic v2 depends on a Rust-backed native module. A pip install on Mac will not work on Lambda.
Lambda Layer Gen fix: Include pydantic, fastapi, and other modern packages in your requirements.txt. We handle the native builds.
Unable to import module 'lambda_function': No module named 'PIL'
Why it happens: Pillow (PIL) requires compiled image libraries. Installing with pip on macOS produces Mac binaries.
Lambda Layer Gen fix: Lambda Layer Gen builds Pillow and other image-processing deps for Amazon Linux automatically.
Lambda layer attached but still getting 'No module named' at cold start
Why it happens: Common causes: wrong python/ directory layout, function zip also bundling the same libs (version conflict), or incompatible runtime.
Lambda Layer Gen fix: Our layer zips follow AWS's required python/lib/python3.x/site-packages structure and match your function runtime.
x86_64 layer on arm64 Graviton function: binaries will not execute
Why it happens: An x86_64-compiled layer cannot run on an arm64 Lambda, and vice versa. The console may block attachment entirely.
Lambda Layer Gen fix: Choose x86_64 or arm64 when generating. We build for the architecture your function actually uses.
Unable to import module 'lambda_function': No module named 'cryptography'
Why it happens: cryptography and bcrypt rely on OpenSSL-linked native code that must be compiled for Amazon Linux 2 or AL2023.
Lambda Layer Gen fix: Add cryptography to requirements.txt and receive a layer with the correct manylinux wheels baked in.
Unable to import module 'lambda_function': No module named 'lxml.etree'
Why it happens: lxml bundles libxml2/libxslt C libraries. A source build on your dev machine will not import on Lambda.
Lambda Layer Gen fix: lxml, beautifulsoup4, and scraping stacks are supported. Built for Lambda, not your laptop.
Fixes Runtime.ImportModuleError, invalid ELF header on Mac/Windows builds, numpy/pandas/psycopg2 native extension failures, and Python 3.10-3.14 layer packaging for x86_64 and arm64 AWS Lambda functions.