Structured intelligence.
Clear signals.
Letinix helps builders understand, compare, and use modern software, AI, and automation tools — with practical guides, fair comparisons and analysis that puts evidence ahead of hype.
Featured
Hand-picked guides, comparisons and analysis.
Frontend Is Easy… Until You Actually Build Something
Every frontend developer has heard some variation of these. "It's just a screen." "Backend does the real work." "AI can generate that." "Just use ShadCN." "Just copy the component." "It's just a checkbox." And every frontend developer
Claude’s Intelligence Isn’t Worth $20 to Me Anymore
I like Claude. That is precisely why I have a problem with Claude Pro. Claude can write exceptionally well. Its coding models are genuinely competitive. Claude Code is one of the strongest arguments Anthropic has made for putting an AI
The One Extra Click That Makes Chrome's Built-in Gemini Feel Less Intelligent
Intelligence isn't just about the model When we talk about AI products, we usually compare models. Qwen vs Gemini. Claude vs GPT-6. Reasoning vs Non-Reasoning . Latency vs Context window vs Benchmarks. Those comparisons matter. But after
Browse by goal
Start from what you need to get done.
Latest
Newest first, across every area.
LLM Input vs. Output Token Pricing: How to Calculate the Difference
Learn how input tokens, output tokens, and cached input affect an LLM API bill, with a worked example and a formula you can reuse across providers.
Oct 23, 2026
How to Validate API Responses in TypeScript
Learn how to validate untrusted API response data at runtime in TypeScript, infer static types from a Zod schema, and decide when JSON Schema or generated types fit better.
Oct 23, 2026
SaaS Unit Economics: Payment Fees and Usage Costs
SaaS unit economics become clearer when you subtract payment-processing fees and customer-driven usage costs from revenue. Here is a practical per-customer contribution model, with assumptions and limits made explicit.
Oct 22, 2026
SaaS Gross Margin: Formula and Cost-of-Revenue Decisions
Learn the SaaS gross margin formula, work through an explicit example, and decide how hosting, support, engineering, and payment fees should be classified in your model.
Oct 22, 2026
How to Estimate LLM API Costs Before Launch
Estimate monthly LLM API spend from input and output tokens, request volume and current model pricing. Learn which assumptions matter and what a token-cost estimate leaves out.
Oct 21, 2026
TypeScript Optional vs. Nullable: Model API Fields Correctly
Understand the difference between optional TypeScript properties and nullable values, and choose the right model for API responses with missing or null fields.
Oct 21, 2026
Is It Safe to Decode a JWT Online?
A JWT decoder can expose claims without verifying the token. Before using an online inspector, understand whether the token is sent to a server, what the token grants, and which inspection workflow your organization permits.
Oct 21, 2026
JWT Decode vs Verify: What Each Step Actually Proves
JWT decoding reveals the header and payload. Signature verification checks cryptographic integrity against an expected algorithm and trusted key; claim validation and authorization are separate decisions.
Oct 21, 2026
Analysis
Evidence-led technical analysis.
Jev Is Not a Paradigm Shift. It’s ust a Fast Classifier.
I called Jev a glorified, high-speed classifier . Then I did the thing controversial posts usually skip: I tried to prove myself wrong. I went through TypeSafe’s launch material, LangChain’s harness and Jev-as-a-Judge experiments , Vercel’s
Does Size Matter? Bigger AI Isn’t Always Better
Does size matter? There. I asked it. Humanity has spent an unreasonable amount of time arguing about this question, so naturally we eventually gave the problem to artificial intelligence. Except now we measure it in billions of parameters .
GPT-6 Astra Is More Aligned. I Still Wouldn’t Trust It With More Autonomy.
I would let GPT-6 Astra do more work. I would not let GPT-6 Astra decide what it is allowed to do. That distinction is more interesting to me than most of the benchmark numbers in OpenAI's launch. OpenAI calls Astra its most aligned model.
An Agent API Migration Is an Ownership Audit
An API migration can compile, return the expected text, and still be wrong. That is the real risk in moving from OpenAI's Assistants API to Responses. The old objects do not map to new objects without changing where configuration, state,
A Tool Result Is Evidence, Not Ground Truth
Connecting an agent to a database does not remove hallucination risk. It gives the system a second source that can be stale, malformed, unauthorized, or simply wrong—and a protocol that may make the model trust it more than it should. Tools
Code Generation Is Fast. Verification Is Not.
Agentic IDEs can produce a runnable full-stack application in minutes. That does not mean the application became cheap to trust. In a controlled study of 48 generated projects, the researchers spent as much or more time manually verifying
Free tools for builders
Calculate, inspect, convert and generate, right in your browser.
JWT Inspector
Decode a JSON Web Token's header and payload and check its time claims.
Cron Expression Builder
Build a cron schedule and read it back in plain English with the next run times.
JSON to TypeScript Converter
Turn a JSON sample into TypeScript types you can paste into a project.
Prompt Formatter
Structure a prompt into clear, labeled sections or tidy an existing one.