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Resolving the Node.js Error: Cannot find module jsonwebtoken

When developing backend services with Node.js, especially APIs that implement authentication, it is common to rely on JSON Web Tokens (JWT). One frequent runtime error encountered in this context is: This article explains the root cause of this error and provides a precise, production-oriented solution. Problem Description The error indicates that Node.js cannot resolve the
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Extracting and Managing Access Tokens in Postman

When working with APIs that use OAuth 2.0 or token-based authentication, a common requirement is to extract an access_token from a successful authentication request and reuse it in subsequent API calls. Postman provides a built-in scripting environment that makes this straightforward and repeatable. This article explains how to capture an access token from a POST
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How PostHog Uses ClickHouse for High-Performance Product Analytics

Modern product analytics platforms must process billions of events while still delivering low-latency queries for dashboards, funnels, and retention analysis. PostHog addresses this requirement by building its analytics engine on top of ClickHouse, a column-oriented OLAP database designed for large-scale analytical workloads. This article focuses exclusively on how ClickHouse is used within PostHog, from data
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Hiding Personal Information in AWS Glue with Spark

Protecting personal data before analytics consumption is a core requirement in modern data platforms. In AWS-based lake architectures, this is typically achieved through data de-identification during ingestion or transformation. This post outlines a practical and production-ready approach to hiding personal information using Spark jobs in AWS Glue. What “Hide Personal Information” Means in Data Engineering
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Automating OAuth 2.0 in Postman: storing and refreshing access tokens without copy-paste

Introduction When working with APIs protected by OAuth 2.0, Postman is commonly used for development and testing. A frequent pain point is manual token handling: requesting an access token, copying it, pasting it into headers, and repeating the process every time it expires.This article explains how to fully automate OAuth 2.0 token management in Postman,
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Running Scheduled GitHub Actions Locally for Safer Debugging

Overview When working with scheduled automation jobs in GitHub Actions, it is common to face a simple but critical question: Can this workflow be executed locally before pushing to production? The short answer is yes, and in many cases, the local execution is functionally identical to what GitHub Actions performs in the cloud. This article
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Designing a Scalable Course Progress Service on AWS

EC2, Lambda, DynamoDB, and RDS Cost and Architecture Trade-offs Context In a multi-platform learning environment where users can advance through courses using both Web and Mobile applications, maintaining a single, consistent view of user progress is critical. In this scenario: This leads to a key architectural decision: introducing a third, independent “source of truth” for
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