StellarFirm vs ThunderPhone

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

StellarFirm compared with ThunderPhone
Detail	StellarFirm	ThunderPhone
What it does	AI Agents that take on the work, from plan to finished result	AI phone agents with integrated audio understanding, model routing, and voice optimization
Stage	Not given	Not given
Founded	Not given	Not given
Based in	GR	US
Pricing model	Not given	Paid
Pricing	Alpha is free with free credits for new accounts. Credit packs available: 1,000 credits, 5,000 credits, 20,000 credits. Plans coming soon.	Cost-plus pricing: customers pay vendor list prices for models and voice plus hosting (15% of vendor costs, 0.5¢ to 2¢ per minute) plus company margin (17-25%). Lean calls cost from 2.0¢/min (1.18¢ vendors + 0.50¢ hosting + 0.35¢ margin). Receptionist calls cost 4.7¢/min (3.36¢ vendors + 0.50¢ hosti
Key features	Approval system for all outputs before publishing Cloud-based workspace accessible from browser Desktop application for Mac and Windows Slack integration for assistant communication	Multi-model architecture running multiple transcription and language models per call Zeus AI agent that builds, tests and tunes voice agents automatically Simulated call testing before live deployment Live call monitoring and observability A/B testing and automated fix suggestions Integration wizard for CRM, VoIP and business software Client portals for managing multiple agents Knowledge base integration for agent grounding Outbound campaigns with CSV upload and scheduling
What makes it different	Human approval required for all outputs that publish or spend money Agents hand work to each other automatically Agents work continuously even when you sleep Choice of cloud hosting or local machine execution	Cost-plus pricing with no margin markup pass-through when vendor prices drop Fully agentic Zeus AI that handles entire lifecycle from creation to optimization Multi-model architecture for superior audio understanding vs 3-step pipelines Starts at 2¢/min, cheaper than competitors and call center labor
Community votes	0	0
DR (Domain Rating by Ahrefs)	29 +1 (up) since last check	43 +1 (up) since last check
Trust Flow (Majestic)	5	5
Citation Flow (Majestic)	38	35
Referring domains (Majestic)	12	161

5 details filled in for both companies.

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