Stammer

Stammer's core proposition is ownership of the client relationship, and the product is built around that rather than around the agent builder itself. The white-label layer covers the custom domain (agents.youragency.com), your logo and colors, a branded client portal, and a white-label API — meaning a client logging in sees your company and gets support from your team. That matters more than feature parity for agencies whose whole business is selling someone else's technology under their own name. The channel coverage is broad for the price. Chat agents go to website embeds, Instagram DM, Facebook Messenger, WhatsApp, SMS, and API, and voice agents handle inbound answering, outbound campaigns, lead follow-up, and appointment reminders. Scheduling pushes bookings into Google Calendar, Calendly, or Cal.com, and human handoff lets your team take over a live conversation. Pro adds MCP support for connecting external data sources and tools, plus bring-your-own OpenAI or Anthropic keys — worth understanding that Stammer's own FAQ says BYO keys skip usage costs on chat messaging only, not voice calls. Voice stays metered no matter what. The wallet model is the real decision point. Stammer's example is buying a GPT-4o chat response for $0.01 and reselling it at $0.05; the published rate card spans roughly $0.0009/message (GPT-5.6 Luna) to $0.01/message (Claude 5 Sonnet), and voice runs $0.11/min (GPT-4.1-nano) to $0.17/min (Claude 3.7 Sonnet). That spread is your gross margin, and picking the model per agent is a pricing lever, not just a quality lever. Clients get their own Sub-Account Wallet and pay you directly for usage, so you're not floating their consumption. Both wallets support manual top-up and auto-recharge, which prevents the classic agency failure of an agent going dark mid-month on an empty balance. Where it gets awkward: Standard at $49/mo includes no white-labeling and no advanced models, so a buyer landing on the cheaper tier for the reseller pitch has bought the wrong plan. Additional agents cost $10/mo each on Pro, extra knowledge-base capacity is $5/mo per 1M characters, and additional concurrent calls are $15/mo — small line items that stack once you're running twenty clients. Enterprise is custom at 1,000+ chat agents and 250+ voice agents with SSO, custom integrations, and optional self-hosting. If you only need one internal chatbot for your own site, the entire reseller layer is dead weight and you should look at a simpler embed tool. If you need email campaign automation, Stammer isn't that either. But for an agency that wants to invoice clients monthly for an AI receptionist under its own brand, the pieces — domain, portal, wallets, per-client reporting — are all in one place.