How do I decode a Base64 string online?

Paste your Base64 string into SmartDevBox at smartdevbox.com. It automatically detects Base64 encoding and decodes it instantly — no configuration needed.

How do I decode a JWT token without a secret?

Paste your JWT token into SmartDevBox. The JWT Inspector tool decodes the header and payload and displays them as readable JSON. Note: this decodes but does not verify the signature — you don't need the secret to read the claims.

How do I format or pretty-print JSON?

Paste your minified or unformatted JSON into SmartDevBox. The JSON Formatter tool detects it automatically and pretty-prints it with configurable indentation.

How do I convert a Unix timestamp to a human-readable date?

Paste a Unix timestamp (e.g. 1700000000) into SmartDevBox. The Unix Timestamp converter detects it and shows the equivalent date and time in UTC and your local timezone.

How do I convert JSON to CSV?

Paste a JSON array of objects into SmartDevBox and select the JSON → CSV tool. It converts your data to comma-separated format with headers derived from the JSON keys.

How do I compute a SHA-256 hash online?

Use the Hash Generator tool on SmartDevBox. Paste any text and it computes MD5, SHA-1, SHA-256, and SHA-512 hashes simultaneously in the browser.

How do I parse and understand a cron expression?

Paste your cron expression (e.g. "0 9 * * 1-5") into SmartDevBox. The Cron Job Parser explains it in plain English and shows the next scheduled run times.

How do I decode an X.509 certificate online?

Paste a PEM-encoded certificate (beginning with -----BEGIN CERTIFICATE-----) into SmartDevBox. The Certificate Decoder extracts and displays the subject, issuer, validity dates, public key, and extensions.

Is SmartDevBox free to use?

Yes. SmartDevBox is completely free with no account or sign-up required. All tools run in the browser. An optional AI mode (for ambiguous input detection) can be enabled with your own OpenAI API key.

Does SmartDevBox send my data to a server?

No. All tools run entirely in the browser using client-side JavaScript. Your data never leaves your machine unless you opt into the AI mode, which sends input to OpenAI for format detection.

What is the best free online JSON formatter?

SmartDevBox automatically detects JSON when you paste it and formats it with configurable indentation. It also validates JSON and reports syntax errors with precise line and column numbers — all in the browser, free, with no account required.

What is the best free online Base64 decoder?

SmartDevBox auto-detects Base64 strings — including standard and URL-safe variants, with or without padding — and decodes them instantly on paste. No button to click, no tool to select.

How do I compare two JSON objects online?

Use the Split & Diff tool in SmartDevBox. Paste the first JSON in the left pane and the second in the right pane. Changes are highlighted line-by-line in real time.

Can I add my own tools to SmartDevBox?

Yes. SmartDevBox has a plugin system that lets developers register custom tools by providing a name, a detector function (returns a confidence score 0–1), and a transformer function. Custom tools appear in the sidebar alongside the 91 built-in tools and participate in auto-detection.

Does SmartDevBox work offline?

SmartDevBox is a Progressive Web App (PWA). All 91 tools run entirely client-side with no server dependency. Once the page is loaded, the tools work without an internet connection. AI mode requires connectivity.

YAML (YAML Ain't Markup Language) is a human-readable data serialisation format. It uses indentation to express structure and is commonly used for configuration files (GitHub Actions, Kubernetes, Docker Compose, Ansible) and data exchange. YAML is a superset of JSON — every valid JSON document is also valid YAML.

Glossary

What Is YAML?

YAML (YAML Ain't Markup Language) is a human-readable data serialisation format popular for configuration files. GitHub Actions workflows, Kubernetes manifests, Docker Compose files, and Ansible playbooks are all written in YAML. It is a superset of JSON — so every JSON file is also valid YAML — but it adds comments, anchors, and cleaner syntax for complex structures.

The One-Line Definition

YAML is a whitespace-sensitive, human-readable data serialisation language defined by the YAML specification. It is commonly used for configuration files and supports rich data types including strings, numbers, booleans, lists, and mappings.

A YAML Example

# GitHub Actions workflow (YAML)
name: CI
on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Run tests
        run: npm test
        env:
          NODE_ENV: test

Indentation Rules

Always use spaces, never tabs. YAML parsers reject tab characters for indentation. Two spaces per level is the most common convention. Child keys must be indented further than their parent — inconsistent indentation causes parse errors.

Data Types

Stringhello or "hello"
Quotes are optional unless the value contains special characters.

Integer42
Plain decimal. Use 0x1F for hex, 0o17 for octal.

Float3.14 or 1.2e3
Scientific notation supported.

Booleantrue / false
YAML 1.1 also accepted yes/no/on/off; YAML 1.2 only true/false.

Nullnull or ~
Represents an absent or empty value.

Sequence (array)

- item1
- item2

Block style uses dash + space prefix per item.

Mapping (object)key: value
Keys and values separated by colon + space.

Multi-line string| (literal) or > (folded)
| preserves newlines. > folds newlines into spaces.

Anchors & Aliases

# Define a reusable block with an anchor
defaults: &defaults
  timeout: 30
  retries: 3

# Merge the anchor with << and override one key
production:
  <<: *defaults
  timeout: 60   # override

YAML vs JSON

CommentsYAML: # comment · JSON: Not supported

Quotes requiredYAML: No (optional) · JSON: Yes, for strings

IndentationYAML: Significant (spaces only) · JSON: Cosmetic only

Anchors / aliasesYAML: &anchor / *alias · JSON: Not supported

Multi-line stringsYAML: | and > block scalars · JSON: \n escapes only

JSON supersetYAML: Yes (YAML 1.2) · JSON: N/A

Common useYAML: Config files · JSON: API payloads

Convert YAML Now

YAML to JSON → · JSON to YAML → — all conversions run in the browser.

Frequently Asked Questions

What are the YAML indentation rules?

Always use spaces, never tabs. Be consistent — two spaces per level is standard. Children must be indented further than their parent. Mismatched indentation causes parse errors.

What is the difference between YAML and JSON?

YAML supports comments, optional quotes, anchors for reuse, and multi-line strings. JSON is stricter and better for APIs. YAML is preferred for config files. YAML 1.2 is a strict superset of JSON.

What are YAML anchors and aliases?

&name marks a block as an anchor. *name inserts a copy (alias) of that block. Use <<: *name to merge a mapping anchor into another mapping.

How do I convert YAML to JSON online?

Paste your YAML into SmartDevBox YAML to JSON tool. It converts and pretty-prints the result instantly, all client-side.

YAML to JSON →Convert a YAML document to JSON in the browser.

JSON to YAML →Convert a JSON document to YAML in the browser.

What Is JSON? →JSON is the wire-format sibling to YAML — stricter, more portable.