DevOps Tools for Configuration You Can Inspect Before Runtime
Infrastructure configuration has a useful pre-runtime layer. Docker Compose files, Kubernetes manifests, GitHub Actions workflows, environment assignments, Nginx rules, cron expressions, DNS answers, and CIDR ranges can all reveal problems before a deployment or incident turns them into runtime symptoms.
Parsing comes before platform validation
A file must first be syntactically readable, but valid YAML alone says nothing about Kubernetes schemas, Compose semantics, or policy enforcement.
Declared state is not observed state
A manifest can describe ports, images, requests, limits, or dependencies without proving that a cluster, runner, resolver, or host will make them work.
Precedence changes outcomes
Environment interpolation, DNS caches, Nginx matching, cron fields, image tags, and configuration defaults can all make apparently similar inputs behave differently.
All DevOps Tools
The 30 tools cover Docker Compose, Dockerfiles, Kubernetes, environment variables, YAML validation and conversion, cron, DNS, CIDR, GitHub Actions, and Nginx configuration.
Cron Expression Generator
Build portable five-field cron expressions field by field, with presets, validation, and day-rule warnings.
YAML to JSON Converter
Parse YAML and serialize the resulting data structure as formatted JSON.
JSON to YAML Converter
Parse valid JSON and serialize its data structure as readable YAML.
Docker Compose Validator
Parse Compose YAML and flag structural or configuration problems before deployment.
Kubernetes YAML Validator
Parse Kubernetes manifests and flag YAML or resource-structure problems before applying them.
.env File Parser
Parse dotenv assignments into structured keys and values for inspection or JSON output.
DNS Records Checker
Check DNS records including A, AAAA, CNAME, MX, TXT, NS, SOA, and domain configuration details.
YAML Validator
Parse YAML syntax and surface indentation or structure errors without rewriting the document.
Dockerfile Linter
Check Dockerfile content for common issues, risky patterns, and basic Dockerfile best practices.
Kubernetes Secret Decoder
Decode Kubernetes Secret YAML values and inspect base64 encoded secret data in your browser.
Nginx Config Validator
Check Nginx configuration snippets for common syntax issues, missing braces, server blocks, and proxy settings.
Cron Expression Validator
Validate and interpret five-field cron syntax, expanded field values, calendar traps, and scheduler boundaries.
DNS Propagation Checker
Compare DNS record answers, response codes, and TTLs from Google and Cloudflare public resolvers.
CIDR Range Expander
Enumerate IPv4 addresses from CIDR blocks with explicit boundary rules and browser-safe output limits.
IPv4 Subnet Calculator
Calculate IPv4 CIDR boundaries, range ends, /31 semantics, binary form, and equal-size subnet splits.
GitHub Actions YAML Validator
Parse workflow YAML and examine triggers, jobs, runners, permissions, action references, and secret risks.
Environment Variable Diff Checker
Compare dotenv assignments while surfacing missing keys, duplicate definitions, empty values, and secret-sensitive changes.
Kubernetes Resource Calculator
Total declared Kubernetes CPU and memory requests or limits across supported workload replicas.
GitHub Actions Matrix Builder
Generate strategy matrices with GitHub-accurate include/exclude expansion, scalar typing, concurrency controls, and job limits.
Docker Compose Ports Checker
Examine published ports, host bindings, ranges, protocols, expose entries, and cross-service collisions.
Nginx Redirect Rule Tester
Simulate scoped Nginx return and rewrite redirects with URL, location, query, and loop checks.
Docker Environment Variable Checker
Check Docker .env and docker-compose environment variables for duplicates, missing values, invalid names, and risky secrets.
Docker Compose Volume Checker
Check Docker Compose volume mounts for duplicate targets, risky host paths, Docker socket mounts, anonymous volumes, and read-only recommendations.
Dockerfile Instruction Explainer
Interpret Dockerfile instructions across parser directives, build stages, runtime settings, and security-sensitive choices.
Docker Compose Service Dependency Visualizer
Trace Compose startup dependencies, shared namespaces, legacy links, and inferred service connections from YAML.
Kubernetes YAML Resource Summarizer
Inventory Kubernetes resources, namespaces, workload images, replicas, ports, hosts, and configuration signals from manifests.
Kubernetes Service Port Mapper
Map Service ports to selected workload ports and Ingress backends across Kubernetes manifests.
Kubernetes Image Tag Checker
Trace Kubernetes container images, tags, digests, pull policies, and registry references across workload manifests.
Kubernetes Resource Requests and Limits Checker
Check container and Pod-level resource declarations for missing fields, invalid quantities, and request-limit conflicts.
Docker Compose Environment Variable Resolver
Resolve Compose interpolation across shell and .env sources with exact fallback, required, and empty-value semantics.
A Configuration Travels Through More Than One Layer
1. Text and syntax
YAML, dotenv assignments, cron fields, CIDR notation, and Nginx snippets must first be parseable. Syntax checks are useful because later tools cannot reason reliably about malformed input.
2. Configuration semantics
Once parsed, relationships start to matter: a Service port must map to something meaningful, resource requests and limits can conflict, Compose mounts can target the same path, and environment values can resolve from several sources.
3. Runtime and policy
The final outcome belongs to the live platform. Kubernetes admission, CRDs, scheduler capacity, registry access, secrets, storage classes, repository permissions, runner state, Docker host settings, and network policy are not visible in a pasted configuration alone.
What These Checks Can Narrow Down Before You Touch Production
Docker-related tools can expose port collisions, risky host mounts, dependency relationships, Dockerfile instruction concerns, and Compose interpolation problems. Kubernetes tools can inventory resources, trace images, map Service ports, summarize manifests, and review declared CPU or memory constraints.
DNS and networking tools answer a different class of question. Resolver comparisons show what selected public resolvers currently return; CIDR calculators explain address boundaries mathematically. Neither proves the path a specific client, corporate resolver, or network appliance will take.
YAML formatting itself is intentionally not in this category. The standalone YAML Formatter belongs to JSON & Data Tools because reformatting data is a representation task. YAML validation and YAML/JSON conversion remain here where they support deployment-oriented workflows.
Primary Platform References
Defines the Compose model behind services, volumes, networks, ports, environment values, and dependencies.
Documents built-in resource fields and semantics that static manifest checks need to interpret carefully.
Covers workflow triggers, jobs, permissions, expressions, matrices, and action behavior used by CI checks.