Design a Production RAG System in 2026
Design a production RAG system with hybrid search, reranking, evaluation, caching, security, capacity planning, and deployment tradeoffs for interviews.
August 3, 2026
Blog
Practical engineering articles: debugging deep dives, framework guides, and patterns you can apply at work and in interviews.
How to Design a Multi-Agent System: Orchestration, Memory, Tool Calling, and Failure Recovery
A production guide to multi-agent orchestration, scoped memory, safe tool calling, durable checkpoints, recovery, evaluation, and interview trade-offs.
August 3, 2026
MCP System Design: Secure Multi-Tenant Gateway
Design a secure multi-tenant MCP gateway in TypeScript with tenant isolation, OAuth, policy enforcement, routing, scaling, testing, and interview tradeoffs.
August 3, 2026
MCP vs A2A vs A2UI: A System Design Guide for AI Agent Architectures
Choose MCP, A2A, or A2UI by architecture boundary, with a protocol decision tree, TypeScript example, failure modes, and interview trade-offs.
August 3, 2026
AI Coding Interviews in 2026: What Senior Engineers Should Prepare For
Prepare for AI-assisted coding interviews in 2026: architecture judgment, agent supervision, debugging, verification, tests, and senior-level communication.
August 2, 2026
Fix RuntimeError: CUDA out of memory (PyTorch)
Fix PyTorch CUDA out-of-memory errors with profiling, batch and sequence controls, AMP, checkpointing, allocator tuning, distributed fixes, and GPU diagnostics.
July 31, 2026
Fix Hydration Failed Errors in Next.js
Fix Next.js hydration mismatch errors by matching server and first client output, debugging dates, storage, invalid HTML, CSS, CDN, and production-only changes.
July 28, 2026
Fix EADDRINUSE: Address Already in Use in Node.js
Fix Node.js EADDRINUSE on port 3000: find the listener safely, resolve duplicate servers, and prevent Docker, WSL, CI, and production port clashes reliably.
July 27, 2026
Fix npm ERESOLVE Dependency Tree Errors
Fix npm ERR! ERESOLVE dependency tree errors by reading peer conflicts, aligning package versions, using overrides safely, and keeping CI installs reproducible.
July 27, 2026
Fix TypeError: datetime Is Not JSON Serializable
Fix Python datetime JSON serialization errors with ISO 8601, timezone-safe encoders, Flask, Django, FastAPI, pandas, debugging, tests, and prevention.
July 27, 2026
Fix AttributeError: 'DataFrame' object has no attribute 'append'
Pandas 2.0 removed DataFrame.append(). Replace it with pd.concat — and if you were appending in a loop, collect rows in a list and build the DataFrame once.
July 25, 2026
Fix ImportError: cannot import name 'Mapping' from 'collections'
Python 3.10 removed the old collections.Mapping alias. Import from collections.abc instead — but it's usually an old dependency, so read the traceback and upgrade it.
July 25, 2026
Fix ModuleNotFoundError: No module named 'cv2' (OpenCV)
You import cv2 but the pip package is opencv-python — and there are four variants. Pick the right one, and preempt the libGL.so.1 error on servers with headless.
July 25, 2026
Fix ModuleNotFoundError: No module named 'dotenv'
The package is python-dotenv but the import is dotenv — and pip install dotenv is the wrong package. Install python-dotenv into the interpreter you actually run.
July 25, 2026
Fix ValueError: too many values to unpack (expected 2)
This means the left side has fewer targets than the right side has values. Count both sides, iterate dicts with .items(), and use star-unpacking for extras.
July 25, 2026
Fix OpenAI RateLimitError (429): The Complete Guide
OpenAI RateLimitError has two causes that need opposite fixes: insufficient_quota (billing) and rate_limit_exceeded (throughput). Diagnose which, then fix it.
July 24, 2026
Fix "Token indices sequence length is longer than the specified maximum"
This Hugging Face message is a warning, not the real error — the crash comes later. Fix it with explicit truncation, and watch for the model_max_length sentinel trap.
July 24, 2026
Fix "bitsandbytes CUDA Setup failed"
If bitsandbytes loads libbitsandbytes_cpu.so, no CUDA binary matched. Upgrade bitsandbytes first, confirm a CUDA PyTorch, then fix the library path.
July 24, 2026
Resolve "ChromaDB collection does not exist"
Two causes account for almost every ChromaDB 'collection does not exist' — using get_collection instead of get_or_create, and an ephemeral client that never persisted.
July 24, 2026
Resolve "CUDA error: device-side assert triggered"
The traceback lies because CUDA runs async. Get the real line with CUDA_LAUNCH_BLOCKING=1 or the CPU, then fix the out-of-range index behind it.
July 24, 2026
Resolve "Hugging Face 401 Unauthorized"
A Hugging Face 401 means the token is missing, invalid, or lacks access. Learn to tell 401 from 403 and 404, and fix gated and private repo access.
July 24, 2026
Resolve "LangChain ValidationError"
A LangChain ValidationError is a Pydantic error — and it names the exact field. Read loc/type/input, and fix the Pydantic v1 vs v2 mismatch behind most of them.
July 24, 2026
Resolve "OSError: Can't load tokenizer"
This Hugging Face error means one of two things: a Hub id that can't be found, or a local folder missing tokenizer files. Learn which, then fix it fast.
July 24, 2026
Fix "SentenceTransformer model download failed"
"Download failed" isn't one error. Triage it by symptom — wrong name, gated auth, network/SSL/proxy, timeout, or a corrupted cache — and apply the right fix.
July 24, 2026
Fix torch.cuda.is_available() Returns False
The fastest test is torch.version.cuda — if it's None you have a CPU-only wheel. PyTorch bundles its own CUDA runtime, so you only need the NVIDIA driver.
July 24, 2026
Angular Unit Testing with Jasmine and Karma: A Practical Guide
How Angular unit testing fits together — TestBed, Jasmine, and Karma — plus code coverage, testing pipes, and testing attribute directives, with examples.
July 21, 2026
Fix CUDA and cuDNN Library Load Errors in TensorFlow: A Diagnostic Guide
Every TensorFlow CUDA library error — libcublas, libcudart, libnvinfer, cuDNN — traced to one of four root causes, with the order to diagnose them.
July 21, 2026
JavaScript Algorithm Interview Problems: 8 Patterns with Solutions
Learn eight JavaScript algorithm interview patterns with worked solutions: array transforms, hashing, interval scans, matrix rotation, and async sequencing.
July 21, 2026
Common Pandas Errors and Gotchas: A Diagnostic Guide
The pandas errors that waste the most time — SettingWithCopyWarning, Int64Index errors, silent assignment failures, and merge row explosions — and their causes.
July 21, 2026
Honesty and Psychological Safety in Engineering Teams
Why engineers overstate confidence in their code — deadline pressure, fear, and review cultures that punish doubt — and the practices that fix it.
May 26, 2026
Google AI Edge Gallery: Running AI Models Directly on Your Phone
Google AI Edge Gallery runs generative AI models fully on-device on Android — no cloud, offline, private. What it does, why it matters, how to start.
May 26, 2026
30 SQL Interview Questions for Experienced Professionals
Scenario-based SQL interview questions and answers for professionals with 6–10 years of experience, covering queries, indexing, tuning, transactions, and scale.
March 23, 2025
Most Frequently Asked Java Interview Questions (2025)
29 frequently asked Java interview questions for experienced developers: JVM internals, OOP, collections, exceptions, and multithreading — with answers.
February 15, 2025
Top 10 Interview Questions and Answers for Senior Software Engineers at Infosys
10 Infosys Senior Software Engineer interview questions — URL shortener design, microservices, CAP theorem, API versioning — each with a model answer.
November 11, 2024
React 19 Update - Unlocking Performance and Developer Experience
Let's delve into the exciting new additions in React 19 and explore how they can empower you to create exceptional web applications.
March 20, 2024
Debouncing in React 19 - Optimizing User Input and API Calls
Debouncing is a powerful technique that delays the execution of a function until a certain amount of time has passed since the last user interaction.
March 20, 2024
Building a Two-Way Binding Hook for React
we can create a custom hook to build a simple two-way binding hook for React similar to Angular ngModel.
December 18, 2023
Angular 17 Automatic Migration to the New Control Flow
Angular 17 automatic migration schematic is a testament to Angular's commitment to ease of use and developer-friendly practices
December 10, 2023
Embracing the Future of Coding with Angular 17's New Control Flow Syntax
The new control flow syntax in Angular 17 brings a modern and streamlined approach to handling common coding structures.
December 10, 2023
New Features in Angular 17: A Comprehensive Guide
Angular 17's headline changes: built-in @if/@for/@switch control flow, deferrable views with @defer, and the automatic migration schematic. A full guide.
December 10, 2023
Deferred Loading with Angular 17 - Enhancing Web Application Performance
Angular 17 performance optimization reaches new heights with the introduction of the defer feature.
December 8, 2023
Creating a Custom Alert in React with TypeScript
Here's a custom alert component without using any external libraries, just using React and TypeScript.
July 25, 2023
Building a Custom React Accordion Inspired by Material-UI
Creating a custom accordion that looks similar to the Material UI (MUI) Accordion can be achieved by adapting the styles to match the Material-UI design.
July 24, 2023
Fix Failure of Keras Model.fit with Mirrored Strategy
Keras model.fit failing under MirroredStrategy is usually a model built outside strategy.scope(), an unscaled batch size, or a non-replica-aware step.
June 23, 2023
InvalidArgumentError Unsupported 'dtype' Value bfloat16
InvalidArgumentError: dtype bfloat16 not in allowed values means the op has no bfloat16 kernel. Cast to float32 with tf.cast, or use mixed precision.
June 23, 2023
Error - Check Failed in tensorflow/core/util/gpu_launch_config.h:129
This error occurs when there is a check failure related to the number of work elements.
June 23, 2023
TensorFlow error message - "InvalidArgumentError Graph execution error"
TensorFlow's 'InvalidArgumentError: Graph execution error' is a generic wrapper — the real cause is usually a shape or dtype mismatch. How to find and fix it.
June 22, 2023
Fix CUDA_ERROR_LAUNCH_FAILED and CUDNN_STATUS_INTERNAL_ERROR in TensorFlow
CUDA_ERROR_LAUNCH_FAILED and CUDNN_STATUS_INTERNAL_ERROR in TensorFlow usually mean a version mismatch or GPU memory exhaustion. How to diagnose and fix.
June 21, 2023
Fix Error - Could not load dynamic library 'libnvinfer_plugin.so.6'
'Could not load dynamic library libnvinfer_plugin.so.6' is usually a harmless TensorRT warning, not an error — TensorFlow still runs on GPU. Here's why.
June 10, 2023
Untraced Functions Warning during Model Saving
The 'Found untraced functions' warning when saving a Keras model is informational, not an error — your model still saves and reloads correctly. Here's why.
June 10, 2023
Troubleshooting IDE Auto-Completion Failure for tensorflow.keras
IDE auto-completion fails for tensorflow.keras because it's a lazy-loaded alias. Import from keras directly so your editor can resolve the module.
June 8, 2023
Relationship between TF.Slim, TF High-Level API, and Keras
How TF-Slim, the TF high-level API, and Keras relate: three abstraction layers over TensorFlow. TF-Slim is deprecated; use Keras in TensorFlow 2.x today.
June 8, 2023
Fix error - ImportError- Cannot Import 'abs'
This error typically occurs due to a conflict with a user-defined variable or function named 'abs' or a circular import issue.
June 8, 2023
Build a CNN for Image Classification with Swift for TensorFlow
Build a CNN for image classification with Swift for TensorFlow (S4TF). Note: S4TF was archived in 2021 — use Python TensorFlow/Keras or PyTorch instead.
June 8, 2023
Fix ImportError: libcublas.so.9.0 cannot open shared object file
This error occurs when a required shared library file named "libcublas.so.9.0" is either missing or inaccessible.
June 7, 2023
Fixing the "Could not load dynamic library 'libcudart.so.11.0'" Error
'Could not load dynamic library libcudart.so.11.0' means TensorFlow was built for CUDA 11.0 and can't find it. Fix the version mismatch or loader path.
June 7, 2023
How to Change default types globally in tensorflow?
Set TensorFlow's default float type with tf.keras.backend.set_floatx, or use mixed_precision for float16/bfloat16. ConfigProto does not control dtypes.
June 6, 2023
Fix TensorFlow Not Detecting CUDA Installed via Conda
Troubleshoot and resolve TensorFlow's failure to detect CUDA installed through Conda, enabling GPU utilization.
June 6, 2023
What are the GPUOptions for Go binding in TensorFlow?
Optimize GPU utilization with TensorFlow's Go binding using GPUOptions. Control memory allocation, growth, and device selection for efficient computations.
June 6, 2023
How to handle class weight for multiple outputs in keras?
Weighting Classes in Multiple Output Models with tf.keras - Custom Loss and Sample Weights Solution
June 6, 2023
How to assign value to a EagerTensor slice?
EagerTensors from tf.constant are immutable, so slice assignment raises AttributeError. Use tf.Variable, or tf.tensor_scatter_nd_update for a modified copy.
June 6, 2023
TensorFlow Lite vs TensorFlow Output: Differences Explained
The advantages of TensorFlow Lite's optimized model size, execution efficiency, and supported operations for mobile and embedded deployments.
June 6, 2023
How to clear GPU memory in tensorflow 2?
Clear GPU memory in TensorFlow 2 by enabling memory growth or setting memory limits. Optimize performance with these simple techniques.
June 6, 2023
How to modify complex store data in sveltejs ?
Update nested data in a Svelte store with store.update() and a spread that returns a new object, so Svelte detects the change and reactivity holds.
May 26, 2023
Efficient Fragment Creation in Svelte.js
Understanding how to optimize the rendering performance of components in Svelte.js by using efficient fragment creation.
May 25, 2023
Understanding the Error Handling API in Svelte Components
Svelte error handling: the await catch branch, <svelte:boundary> in Svelte 5, and +error.svelte in SvelteKit. There is no <svelte:error> element.
May 25, 2023
How to set slots after component instance is created in Svelte.js?
Explore the powerful capabilities of Svelte.js in dynamically setting slot content within components even after their instance creation.
May 24, 2023
Creating a Custom Filter in ag-Grid
Create a custom filter in ag-Grid by implementing a filter component with doesFilterPass and registering it on the column. A step-by-step walkthrough.
May 21, 2023
Fix: Unable to Retrieve JDBC Result Set for SELECT * FROM TABLE
'Unable to retrieve JDBC result set' means a wrong table name, missing permissions, invalid SQL, or a closed connection. How to diagnose each cause.
January 21, 2023
How to convert a date to Unix epoch time in Python?
Convert a date to Unix epoch time in Python with dt.timestamp(). Handle timezones correctly so a naive datetime isn't misread as local time.
January 11, 2023
Fix TypeError: Can Only Concatenate str (Not "NoneType") to str
Fix Python's str and NoneType concatenation error by finding the None value, repairing missing returns, choosing safe defaults, and avoiding common bad fixes.
January 10, 2023
How Does Inheritance Work in Python?
Explanation of what inheritance is and why it's important in object-oriented programming
January 9, 2023
Object-Oriented Programming in Python Understanding Classes and Objects.
Python Classes and Objects Building Blocks of Object-Oriented Programming
January 9, 2023
Understanding Polymorphism in Python - How to Write Reusable Code
Polymorphism in Python refers to the ability of a derived class to be used in the same way as its base class. This allows for more flexibility and code reuse
January 8, 2023
OOPS Concept In Python interview questions
OOPS, or Object-Oriented Programming Systems, is a programming paradigm that is based on the concept of objects, which have properties and methods.
January 7, 2023
A guide to the data science life cycle
The six stages of the data science life cycle — define, collect, explore, model, evaluate, deploy — and why the process is iterative, not linear.
January 5, 2023
Seaborn for Data Visualization in Python
Seaborn is a statistical plotting library on top of matplotlib. It works with pandas DataFrames and offers concise, attractive charts. Getting started.
January 5, 2023
Correlation is a part of multivariate analysis? Explained
Correlation measures the linear relationship between two variables and is one building block of multivariate analysis. How they relate, and the caveats.
January 4, 2023
What happens in anomaly detection?
Anomaly detection is the process of identifying unusual patterns or events in data that do not conform to an expected behavior
January 4, 2023
Forms of Discriminant Analysis Explained in Details
Discriminant Analysis is a powerful tool for understanding and predicting the relationships between variables
January 3, 2023
How to fix AttributeError- 'Int64Index' object has no attribute 'month'?
To fix this error, you will need to make sure that you are only trying to access the month attribute of objects that have this attribute
January 3, 2023
How to Append Multiple Excel Files together in python?
Append multiple Excel files in Python: read each with pandas, collect them in a list, then pd.concat once. Why concatenating in the loop is slow.
January 2, 2023
How to fix Error 524 while running jupyter lab in google cloud platform?
Error 524 running JupyterLab on GCP is a Cloudflare timeout from a long-running cell or proxy. Fix it with background jobs, SSH forwarding, or higher limits.
January 2, 2023
Extend Apache Airflow with Custom Operators and Tasks
Learn how to extend Apache Airflow with custom Operators and Tasks. Follow our step-by-step guide with examples to enhance your workflow automation.
January 1, 2023
How to set up Apache Airflow on your local machine?
To set up Airflow, you'll need to have Python and a few other dependencies installed on your machine.
December 29, 2022
A Beginner's Guide to Apache Airflow
Apache Airflow is an open-source platform to programmatically author, schedule, and monitor workflows.
December 28, 2022
Pandas drop rows vs filter with examples
pandas drop removes rows or columns by label; boolean masking and filter select rows by condition. When to use each, with worked examples.
December 27, 2022
How to implement custom loss function in scikit-learn?
To implement a custom loss function in scikit-learn, we'll need to use the make_scorer function
December 25, 2022
How to use XGBoost in Python?
Use XGBoost in Python via its scikit-learn API (XGBClassifier/Regressor) or native DMatrix API. Key hyperparameters and early stopping explained.
December 24, 2022
What is the difference between 'transform' and 'fit_transform' in sklearn?
Understanding the difference between transform and fit_transform is important for effectively using sklearn to prepare your data for modeling
December 21, 2022
How to load a model from an HDF5 file in Keras?
In this post, we will look at how to load a model from an HDF5 file in Keras
December 21, 2022
Difference between StratifiedKFold and StratifiedShuffleSplit in sklearn
StratifiedKFold makes k non-overlapping folds (every sample tested once); StratifiedShuffleSplit draws independent random splits. When to use each.
December 20, 2022
How to plot multiple pandas columns
Here is example of how to plot multiple columns from a Pandas DataFrame
December 19, 2022
How can repetitive rows of data be collected in a single row in pandas?
Collecting repetitive rows of data into a single row can be useful for data cleaning and data analysis purposes.
December 18, 2022
Getting started with PyTorch
Get started with PyTorch: install it, create GPU-accelerated tensors, build a model with nn.Module, and train with autograd. A beginner's tutorial.
December 17, 2022
Fix Firebase code 400 "message" - "CONFIGURATION_NOT_FOUND" error
Firebase 400 CONFIGURATION_NOT_FOUND means the sign-in method isn't enabled. Enable the provider in Authentication and check your apiKey/projectId.
November 6, 2022
How to install wget in macOS?
macOS does not ship with wget. Install it with Homebrew using brew install wget, or build from source with MacPorts as an alternative.
October 22, 2022
How to fix Python ImportError: lxml not found, please install it
Python: ImportError: lxml not found, please install it
October 20, 2022
Fix AttributeError: module 'pexpect' has no attribute 'TIMEOUT'
AttributeError: module 'pexpect' has no attribute 'TIMEOUT' means a stale module is loaded or a local file shadows the package. How to tell which, and fix it.
October 20, 2022
How to fix SettingWithCopyWarning in Pandas?
SettingWithCopyWarning means pandas can't tell if you're modifying a view or a copy, so your assignment may silently do nothing. The view-vs-copy .loc fix.
October 16, 2022
Fix “Max Retries Exceeded with URL” in Python Requests
Fix Python Requests Max retries exceeded errors by identifying DNS, refused connection, timeout, TLS, proxy, or HTTP-status causes before adding retries.
October 14, 2022
How to use ternary conditional operator in Python?
Python's ternary is a conditional expression: value_if_true if condition else value_if_false — not C-style condition ? a : b. Syntax, examples, and limits.
October 14, 2022
Testing Pipes in Angular With Jasmin And Karma
Test Angular pipes with Jasmine and Karma. Pure pipes need no TestBed — instantiate the class and assert on transform(). A step-by-step walkthrough.
October 13, 2022
How To Write Unit Tests For Angular Attribute Directives
Test Angular attribute directives with a standalone host component, TestBed, By.directive, input changes, and assertions for default and bound behavior.
October 12, 2022
Fix: Refused to set unsafe header Origin (XMLHttpRequest)
Origin is a forbidden header — browsers set it and silently refuse setRequestHeader overrides. Why the restriction exists and the server-side CORS fix.
October 11, 2022
How to excludes files from Angular Unit test code coverage
How to excludes mock files from ng test --code-coverage
October 5, 2022
Angular Unit Test Code Coverage with Karma
Generate Angular code coverage with ng test --code-coverage, read the HTML report, enforce thresholds in karma.conf.js, and exclude files that shouldn't count.
October 4, 2022
Sequential Promise using reduce method.
Resolve multiple promises in sequence and return a promise using reduce method
September 27, 2022
Rotate Image
You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise).
September 26, 2022
Given a set of distinct integers array, return all possible subsets.
Given a set of distinct integers array ```myArray```, return all possible subsets (the power set).
September 25, 2022
Missing Number In An Array
Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array.
September 24, 2022
Create User a Function User with username and password property and method checkPassword
set a username and password property on the user object that is created,create a method on User called `checkPassword`
September 17, 2022
How to Square numbers in Array
should return square array.
September 15, 2022
Truth Check using Javascript
Check if the predicate (second argument) is truthy on all elements of a collection (first argument).
September 14, 2022
Merge Intervals using Javascript
Given a collection of intervals, merge all overlapping intervals.
June 14, 2021
Group Anagrams using Javascript
Group anagrams in JavaScript with a hash map keyed on each word sorted alphabetically. O(n·k log k) with a single pass. Solution and test cases.
May 22, 2021