Free Online Developer Tools

Format JSON, inspect JWTs, and convert URL/Base64 instantly

Fast tools for development and QA workflows. All processing runs locally in your browser without uploading your data.

Tool Directory

All tools in one place

Every tool follows the same interaction model: paste input, review output, and copy results. This keeps your debugging flow fast across JSON, JWT, Base64, URL, UUID, and hash tasks.

JSON Formatter

Format, minify, and inspect JSON in your browser. Useful for API payload debugging and request body checks.

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Base64 Encoder

Encode plain text into Base64 for headers, payload testing, and data transport workflows.

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Base64 Decoder

Decode Base64 strings back to readable text and validate malformed input quickly.

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UUID Generator

Generate UUID v1 and v4 values in bulk for fixtures, test data, and temporary identifiers.

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URL Encoder

Encode URL components and query parameters so redirects and OAuth flows do not break.

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URL Decoder

Decode percent-encoded URL strings and inspect readable values in seconds.

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Hash Generator

Generate MD5, SHA-1, SHA-256, and SHA-512 hashes in your browser for quick integrity checks.

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JWT Decoder

Decode JWT header and payload locally to inspect claims without sending tokens to a remote service.

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Benefit

Instant results with no waiting time

Benefit

Copy/paste workflows for API and debugging tasks

Benefit

Consistent experience across all tool pages

How It Works

Use the tools in three simple steps

  1. 1Choose a tool based on your current debugging or integration task.
  2. 2Paste your input, review the output in real time, and copy the result.
  3. 3Move to the next tool without changing workflow patterns or controls.

Choose Faster

Which tool should you use?

TaskBest ToolGo
Clean and validate API payloadsJSON FormatterOpen
Inspect token claims quicklyJWT DecoderOpen
Encode values for query stringsURL EncoderOpen
Decode callback URLs safelyURL DecoderOpen
Generate random IDs for test dataUUID GeneratorOpen
Create checksum fingerprintsHash GeneratorOpen

Use Case

API Debugging

Format JSON responses, inspect JWT claims, and decode URL parameters in one workflow.

Use Case

Auth and Security Checks

Generate hashes, inspect tokens, and validate encoded content before deployment.

Use Case

QA and Test Data

Generate UUIDs, convert Base64, and prepare reproducible test payloads quickly.

Privacy and Performance

Built for sensitive development workflows

DevTools Now is designed for developers who need quick output without exposing internal payloads to third-party services. Data processing happens locally in your browser session.

This local-first approach helps teams troubleshoot API responses, inspect token payloads, and generate identifiers with less friction and better control over sensitive input.

  • Runs locally in your browser
  • No data transfer
  • No sign-up required
  • Free to use

Problem-Based Guide

How to decode JWTs safely during debugging

Safe JWT debugging starts with a clear separation between decoding and verification. Decoding helps you inspect claims such as exp, aud, and iss. Verification confirms the token can actually be trusted.

A practical workflow is: decode locally, check claim semantics, then validate signature and issuer policy in your backend or identity layer. This prevents false confidence from readable but unverified token data.

Use the JWT Decoder for claim inspection and pair it with your server-side validation logs for final security decisions.

Problem-Based Guide

JSON formatter for API debugging workflows

API incidents often involve malformed payloads, hidden nesting changes, and subtle type mismatches. A JSON formatter makes structural issues visible immediately, especially when reviewing webhook bodies and request fixtures under time pressure.

Teams usually debug faster when they normalize JSON first, then compare old and new payload structures. This reduces guesswork in incident channels and creates clearer handoffs between frontend, backend, and QA.

Open the JSON Formatter to validate syntax, switch view modes, and copy a normalized payload for issues, PRs, or postmortems.

Practical Playbook

A simple workflow for faster production debugging

Start by normalizing payloads with the JSON Formatter so your team reviews the same structure. If request parameters or callback payloads include encoded values, continue with URL or Base64 tools to reveal clear text before escalating.

For authentication incidents, inspect JWT claims locally to confirm token scope and expiry assumptions. Then correlate decoded claim data with backend auth logs and policy checks to confirm where access validation fails.

In cross-team incident channels, share both raw and normalized variants when possible. That keeps context complete while still making payload issues readable for engineers, QA, and support teams.

Search-Driven Guidance

When to use each developer tool

Use a JSON formatter for API debugging when responses are deeply nested or partially malformed. Use a JWT decoder when claim mismatches, expiry windows, or audience checks break authentication flows.

Use URL encode/decode tools when redirect parameters fail or callback values are unreadable. Use Base64 tools when metadata, token fragments, or transport wrappers need quick conversion during integration testing.

For release verification, hash generation helps compare artifacts and payload fingerprints, while UUID generation speeds up fixture creation for repeatable QA scenarios.

Team Workflow

How teams use DevTools Now in daily delivery

Product teams often combine these tools inside a single debugging loop: inspect payloads, decode encoded values, verify token claims, then generate reproducible identifiers for tests. Keeping this flow in one interface reduces context switching during releases.

During incident response, standardized tool usage improves communication quality. Engineers can share normalized payloads, decoded claim snapshots, and checksum outputs in a format that is consistent across backend, frontend, QA, and support teams.

The long-term benefit is operational clarity: fewer ambiguous bug reports, faster root-cause analysis, and more reliable handoffs between implementation, verification, and production support.

Implementation Notes

What makes this tool stack practical in real projects

Real project timelines rarely allow long context switches between multiple utilities. A practical tool stack needs consistent controls, predictable output behavior, and clear copy actions so engineers can move from diagnosis to fix without friction.

DevTools Now is structured around that workflow: inspect, transform, validate, and share results. Whether you are reviewing API payloads, analyzing JWT claims, or preparing test fixtures, each step is designed to fit into a repeatable engineering routine rather than a one-off utility interaction.

For teams aiming at faster delivery and fewer regressions, this consistency matters. It lowers cognitive load in incident situations and creates a reusable debugging pattern that scales from individual tasks to cross-team release processes.

Release Readiness

How to use these tools in pre-release QA

Before shipping changes, teams can run a quick payload quality pass: format response samples, decode callback parameters, inspect authentication claims, and generate deterministic comparison values where needed. This process catches a large share of integration defects before production traffic is affected.

For API-heavy releases, include one representative request and response example per critical endpoint. Validate that values are encoded exactly once, token claims match environment rules, and fixture IDs are stable across test reruns. Small checks here usually prevent costly rollback cycles later.

In post-release monitoring, these same tools help confirm whether observed errors come from malformed data, configuration drift, or upstream system changes. Reusing the same debugging workflow before and after release improves both delivery speed and operational reliability.

FAQ

Frequently asked questions

Do you store my input?

No. Input stays in your browser and is not sent to a server.

Can I use these tools with sensitive data?

Yes, processing is client-side. Still, use caution with production secrets.

Do the tools work on mobile?

Yes. The interface is responsive and works on desktop and mobile devices.

Which tool should I use for API payload issues?

Start with JSON Formatter for payload shape checks, then use URL and Base64 tools for encoded fields.

How can I decode JWTs safely during debugging?

Decode tokens locally to inspect claims, then verify signatures and issuer/audience rules in your backend.

Are these tools useful for production incidents?

Yes. They are designed for fast troubleshooting, but you should still avoid sharing full sensitive tokens publicly.