Categories

Jacar categories — explore the topics A rocket whose eyes follow your cursor.
Artificial Intelligence

Mature LLM-as-judge: when to trust and when not

Using an LLM to judge another LLM became widespread in 2024 and remains, in 2026, the only scalable way to evaluate qualitative quality in LLM systems. It is reliable when judge-human correlation exceeds 0.7 on 30 cases and gets recalibrated quarterly; below that threshold, do not trust the number.

Methodologies

AI-integrated DevOps tools in my daily flow

After fourteen months testing AI-integrated DevOps tools across several teams, the stack that stays is small: Claude Code, Cursor, and Aider for code; PagerDuty AIOps, Datadog Bits AI, and Grafana Assistant for alert triage; and OpenTofu with OPA for infrastructure generation bounded by policy rules.

Artificial Intelligence

AI agent incidents: recovery runbooks that work

AI agents fail in production, and what matters is how you respond in the first twenty minutes. This runbook covers severity classification, isolating before investigating, purging contaminated memory, communicating without inventing facts, and turning every incident into a regression test before closing it as done.

Methodologies

RICE: a prioritization framework for product roadmaps

The RICE framework is a prioritization methodology created by Intercom that produces a score by combining four factors: Reach, Impact, Confidence, and Effort. It divides the product of the first three by the estimated effort in person-months, so it can compare unrelated initiatives using one objective number.

Artificial Intelligence

Prompt Engineering: From Trick to Mature Discipline

Prompt engineering has moved from viral tricks to a discipline with reproducible patterns: few-shot, chain-of-thought, and structured output with function calling. Teams treating prompts like code (versioned, tested, and monitored) get consistently better results than those who improvise.

Architecture

Consolidated platform engineering: who wins and who gets stuck

Tres años después de que platform engineering se convirtiera en palabra de moda, el polvo ha caído. Unas pocas empresas tienen plataformas internas que de verdad aceleran al desarrollo, muchas montaron un portal Backstage vacío y algunas volvieron a DevOps clásico. Análisis de qué distingue a las que ganaron.

Artificial Intelligence

FinOps for AI workloads in 2026: the real pain

La factura de IA en las empresas ha dejado de ser anecdótica. Entre tokens de modelos frontera, GPUs reservadas que nadie usa y pipelines RAG con cachés mal configuradas, muchos equipos pagan diez veces lo que deberían. Guía de FinOps específico para IA sin relatos promocionales.

Artificial Intelligence

LLM guardrails: frameworks and their real cost

Guardrails frameworks promise to filter language-model inputs and outputs to block data leaks, harmful content, or hallucinations. After evaluating four of the most popular ones in production, I cover what they actually do, what latency and billing cost they add, and when they pay off over simpler controls.

Architecture

Platform engineering: consolidation after the boom

After three years of expansion and an overheated ecosystem around the term, platform engineering enters 2025 in a consolidation phase. The internal platforms that survive are the ones that understood their real function; those that mistook the label for the solution are dismantling their teams or cutting them drastically.

Artificial Intelligence

Testing with AI: the determinism problem

Probar sistemas que incluyen modelos de lenguaje rompe la primera regla del testing: la misma entrada da la misma salida. Analizo las estrategias que han funcionado tras un año largo integrando IA en productos reales, por qué los tests deterministas tradicionales no bastan y cómo plantear un cinturón de pruebas que capture regresiones sin bloquearse en la varianza.

Methodologies

User research in the age of generative AI

Los equipos de producto están tentados de sustituir entrevistas y tests reales por síntesis de IA. Dos años de experiencia ya permiten separar dónde la IA ayuda de verdad y dónde genera una falsa sensación de entender al usuario.

Methodologies

SLSA v1.0: a mature framework for the software supply chain

SLSA v1.0 splits software supply-chain security into three tracks (Build, Source, and Dependencies), of which only Build is stabilized, with three levels: L1, L2, and L3. If you build in GitHub Actions, reaching L2 with Sigstore-signed provenance takes a few hours and is the starting point I recommend to any team.

Artificial Intelligence

How to Evaluate a RAG System Without Fooling Yourself

Measuring RAG quality rigorously takes more than skimming a handful of answers: it requires objective metrics (faithfulness, relevance, context precision, and coverage), a golden set of hundreds of curated questions, and regular human validation of the LLM judge to avoid misleading conclusions.

Methodologies

Green Software Principles: A Checklist for Teams

Software is not immaterial: every request and database query consumes electricity with a carbon footprint. The Green Software Foundation encodes eight practical principles to reduce that footprint without rewriting systems. The result is a more efficient service, a lower cloud bill, and readiness for ESG regulation.

Architecture

Kubecost and OpenCost: Native FinOps in Kubernetes

Kubecost and OpenCost map real costs to namespaces, deployments, and labels in Kubernetes. OpenCost, the Apache 2.0 open-source core, covers essentials for free. Kubecost adds multi-cluster visibility and advanced cloud billing. For clusters spending over $5,000/month the ROI is clear: identified savings typically exceed software cost within the first month.

Methodologies

Chaos Engineering in Enterprise: Beyond Chaos for Chaos’s Sake

Chaos engineering is the practice of injecting real-world failures into production in a controlled way to verify that the system responds as expected. It requires prior hypotheses, a minimal blast radius, and mature observability. Open-source tools like Litmus and Chaos Mesh make adoption accessible without commercial spend; the ROI comes as avoided incidents and better-prepared teams.

Methodologies

Ansible and Pulumi: Two Automation Philosophies Coexisting

Ansible and Pulumi solve different problems and are not competitors: Ansible manages configuration inside a server (packages, users, services); Pulumi defines, with real code in TypeScript, Python, Go or .NET, which cloud infrastructure exists (VPCs, instances, databases). Combining them, with Pulumi's dynamic inventory feeding Ansible, is the most productive pattern for automating a stack that includes servers in the cloud.

Artificial Intelligence

Retrieval Evaluation Frameworks: Ragas and Similar

Evaluating a RAG system without metrics is pure guesswork. Ragas measures four core signals: faithfulness, answer relevancy, context precision and context recall, using an LLM as judge. TruLens, DeepEval and other frameworks cover similar ground. Wiring evaluation into CI from day one catches regressions in prompts, chunking or model choice before they reach production.

Methodologies

Sigstore in Image Registries: Adoption and Reality

Sigstore has become the standard signing layer for OCI artefacts. GHCR is the best-integrated registry; Harbor 2.5+ and Quay offer native support; AWS ECR pushes its own KMS scheme. Verification earns its keep at three points: the cluster admission controller, the GitOps layer, and the CI/CD pipeline. The public Rekor has rate limits that force self-hosting past a certain build volume.

Methodologies

Observability and SLOs: Error Budgets That Get Met

SLOs and error budgets only work when the budget drives real decisions. A feature freeze that triggers on exhaustion, deploy velocity that adjusts to consumption. With two or three well-chosen SLIs, a clear freeze policy, and simple tools like Prometheus with Sloth, a team can sustainably balance velocity and reliability in production.

Methodologies

Blameless Post-Mortems: How to Actually Improve

Blameless post-mortems are easy to proclaim but hard to execute well. Without genuine blame-free culture, a factual timeline, honest contributor analysis, and action items with a clear owner and deadline, the exercise degenerates into empty ritual that does nothing to prevent the same incidents from recurring.

Architecture

Backstage, Port and Cortex: Three Paths to the IDP

An Internal Developer Platform (IDP) centralises service discovery, provisioning and observability in a single portal, so developers stop depending on stale wikis and Slack channels. Backstage, Port and Cortex dominate the market: Backstage is open source with a dedicated team, Port is fast low-code SaaS, and Cortex focuses on scorecards for measurable technical discipline based on team size.

Methodologies

SaaS Consolidation: When Lock-In Becomes Risk

The SaaS market is consolidating after years of fragmentation: private equity acquisitions, licence changes, and double-digit price hikes have shifted negotiating power toward vendors. A practical framework to audit your exposure, build credible migration pressure, and design exit strategies that work when you actually need them.

Methodologies

Practical DevSecOps with Sigstore and cosign

Signing images and artifacts with Sigstore has stopped being a rare experiment: projects like Kubernetes already use it. The keyless model in cosign, Fulcio, and Rekor removes private-key management, but it only protects you if deployment verifies who signed, not just whether a signature exists.

Methodologies

Flux CD vs ArgoCD: Which to Choose for Your Platform

Flux CD and ArgoCD are the two CNCF-graduated GitOps tools for deploying to Kubernetes with Git as the source of truth. ArgoCD offers a centralised visual UI that manages several clusters from one instance, while Flux is a set of Kubernetes-native controllers with built-in image automation. Neither choice is wrong: it depends on your team and use case.

Architecture

GitOps With ArgoCD: From Hype to Stable Production

ArgoCD has established GitOps as the standard deployment practice for Kubernetes: the Git repository is the single source of truth for the desired state, and the agent continuously reconciles the cluster. This guide covers the four formal GitOps principles, sync policies, common production mistakes, and a comparison with Flux.

Architecture

Platform Engineering: Internal Developer Platforms

Platform engineering formalizes the internal product development teams need. An Internal Developer Platform (IDP) centralises deployment, observability and self-service behind a unified interface so product teams deliver value without becoming infrastructure experts. Investment pays off from around 30 to 50 developers.

Methodologies

SLSA Level 3: Hardening the Software Supply Chain

SLSA v1.0, published in April 2023, defines four maturity levels for securing the software supply chain, from basic provenance to isolated builds. Level 3 requires every build to run in an ephemeral, stateless environment, eliminating attacks like build contamination and insider threat, and is achievable with GitHub Actions and OIDC signing via Sigstore.

Methodologies

FinOps: Controlling Cloud Cost Without Slowing the Team

FinOps turns cloud cost into an engineering discipline rather than a finance problem. The Inform-Optimize-Operate framework delivers per-team visibility, continuous waste reduction, and cost SLOs. Rigorous tagging and open-source tools like Kubecost or Infracost let teams regain control of the bill without slowing delivery.

Methodologies

Applying Google’s SRE Book Without Being Google

Google's SRE book (2016) is canonical reading, but it is written for thousands of engineers and in-house datacenters: applying it literally on a small team creates friction. Five principles do travel (SLOs, error budgets, blameless postmortems, toil management, humane on-call); what does not scale is Google's infrastructure and dedicated roles.

Methodologies

Contract Testing with Pact for Microservices

With 30 or more microservices, end-to-end tests become slow, fragile and impractical. Pact implements consumer-driven contract testing: the consumer defines what it expects, the provider verifies it in its own CI pipeline, with no shared environment needed. The result is integration proof in seconds, not minutes.

Methodologies

Prometheus: Writing Alerts That Won’t Get Ignored

To write Prometheus alerts that won't get ignored, alert on customer-observable symptoms (latency, error rate, saturation) instead of internal causes like CPU or memory, define SLOs with multi-window burn rate to scale severity, add a watchdog alert that confirms the system is still alive, and review the signal-to-noise ratio every quarter.

Methodologies

MoSCoW Method: Effective Requirements Prioritisation

The MoSCoW method organises project requirements into 4 categories: Must have (essential), Should have (important), Could have (desirable), and Won't have (out of scope). Its purpose is to force an explicit priority conversation before committing team resources and time.

Methodologies

The Kano Model: Improving Customer Satisfaction

The Kano model classifies product features into three types: basics (what customers take for granted), performance (where more investment yields more satisfaction), and emotional delighters (unexpected extras that build loyalty). Knowing which category each feature belongs to sharpens every roadmap decision.

Methodologies

Design Thinking: Methods and Strategies

Design thinking is a user-centred problem-solving methodology structured around five iterative phases: empathise, define, ideate, prototype, and test. Following the Design Council Double Diamond model, it first identifies the right problem, then designs the right solution. Applicable to digital products, internal processes, and business models alike.

Methodologies

OKR Methodology: Maximise Your Objectives

The OKR (Objectives and Key Results) methodology is a goal-management system that aligns the entire organisation, from the CEO to every team, around ambitious, measurable goals. Each qualitative objective pairs with quantifiable key results, reviewed every quarter to keep focus without the rigidity of an annual plan.

Methodologies

Agile Methodologies: Optimising Project Development

Agile methodologies (Scrum, Kanban, Extreme Programming) replace rigid upfront planning with short, iterative cycles: each sprint delivers working software, brings in real customer feedback, and lets teams correct course before a mistake becomes expensive. Born from the 2001 Agile Manifesto, they are now applied well beyond software, in marketing, design, and research too.

Methodologies

Methodologies for Defining Objectives: A Strategic Approach

SMART, OKR, and Balanced Scorecard are the three reference methodologies for defining strategic objectives: SMART validates that each objective is specific and measurable, OKR vertically aligns organisational ambition through quarterly reviews, and Balanced Scorecard connects financial indicators with processes, customers, and learning across four complementary perspectives.