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CurlyJSON vs TestFlows Machine

A side-by-side comparison built from both listings. Blank cells mean the company has not given that detail; we never guess.

CurlyJSON compared with TestFlows Machine
DetailCurlyJSON logo CurlyJSONTestFlows Machine logo TestFlows Machine
What it doesJSON Formatter & Validator — Free, Private & Offline Run your programs deterministically. Record, replay, and branch your runs.
StageNot given Not given
FoundedNot given Not given
Based inNot given Not given
Pricing modelFreemium Freemium
PricingFree for all tools. Pro: $29.99 per year or $4 per month, plus tax. Free: €0 with ₡3 credits included each month (about 20 vCPU-hours). Starter: €10/month with ₡25 credits (about 166 vCPU-hours). Plus: €25/month with ₡65 credits (about 433 vCPU-hours). Pro: €50/month with ₡150 credits (about 1,000 vCPU-hours). Dedicated: contact sales. Usage credits: €1 a credit, pu
Key features
  • Validate JSON with precise line and column errors
  • Repair invalid JSON fixing trailing commas, quotes, and comments
  • Preserve large integers without rounding
  • Detect and mask API keys, tokens and passwords
  • Record runs with non-deterministic inputs pinned down
  • Replay runs instruction-by-instruction
  • Checkpoint and fork from any point
  • Fault injection for disk, network, clock, containers and system calls
  • Built-in debugger for machine programs
  • Machine client and Python SDK
  • Cloud storage for runs and disk images
  • Multiple simultaneous sessions with configurable vCPUs
  • Configurable session disk up to 256G
What makes it different
  • Keeps large numbers exactly as written instead of silently rounding them like most online formatters
  • All free tools run entirely in your browser, working offline without uploading data
  • Automatically detects and warns about secrets like API keys and passwords
  • Deterministic replay of program runs with identical outcomes
  • Fork and branch from any point without losing original timeline
  • Comprehensive fault injection testing built-in
  • Pay-as-you-go usage credits with free plan available
Free planNot given Not given
Open sourceNot given Not given
PlatformsNot given Not given
Public APINot given Not given
Community votes00
DR (Domain Rating by Ahrefs)Not checked yet no change since last check2 no change since last check
Trust Flow (Majestic)74
Citation Flow (Majestic)1321
Referring domains (Majestic)227

5 details filled in for both companies.

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