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Responsive Tool 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.

Responsive Tool compared with TestFlows Machine
DetailResponsive Tool logo Responsive ToolTestFlows Machine logo TestFlows Machine
What it doesFree responsive website checker for mobile, tablet and desktop Run your programs deterministically. Record, replay, and branch your runs.
StageNot given Not given
FoundedNot given Not given
Based inNot given Not given
Pricing modelFree Freemium
PricingNot given 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
  • Test multiple device viewports simultaneously
  • Real CSS viewport rendering
  • Share setup links
  • Custom pixel width testing
  • No installation required
  • Sync scroll across panes
  • Browser-based with no account needed
  • 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
  • Compare multiple real device widths side by side instead of switching one at a time
  • Faster than DevTools for checking several device sizes at once
  • Entirely browser-based with no setup, signup or download
  • Built and maintained by one developer in the open
  • 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)14
Citation Flow (Majestic)2521
Referring domains (Majestic)1427

4 details filled in for both companies.

More alternatives to Responsive Tool More alternatives to TestFlows Machine

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