comparison · agency platforms
Hermes vs Stammer in 2026: Pricing, Infrastructure Control, and Which Platform Scales With Your Agency
By builders, for builders.
Both Hermes and Stammer target AI voice agency operators who want to resell voice AI services under their own brand. They look similar at first glance: white-label portals, multi-client dashboards, branded experiences for end clients. The difference becomes structural when you look at what sits underneath. Stammer is a wrapper built on Vapi. Hermes is a purpose-built agency operating platform with its own voice infrastructure, native CRM, and campaign engine. This comparison covers pricing, infrastructure control, upstream risk, feature depth, and when each platform makes sense.
Full disclosure: I am the CEO of Hermes, so this comparison reflects my perspective. I have tried to characterize Stammer accurately. If anything is outdated, reach out and I will correct it.
Side-by-side comparison
| Feature | Hermes | Stammer |
|---|---|---|
| Entry pricing | $149/mo (Starter) | ~$97/mo (published 2026) |
| Included minutes | 300 min (Starter), 1,000 (Business) | Varies by plan; underlying Vapi minutes |
| Overage rate | $0.24/min | Passes through Vapi pricing + markup |
| Infrastructure control | Hermes-owned stack | Wrapper on Vapi (upstream risk) |
| White-label portal | Full CNAME, your brand only | Sub-account white-label via Vapi layer |
| Multi-workspace (multi-client) | 3 to 20+ workspaces per plan | Sub-account model |
| Native CRM | Yes, per workspace | No native CRM |
| Campaign engine (outbound) | Yes, native | No native outbound campaigns |
| Billing per client | Per-workspace P&L | Manual or Stripe integration required |
| Upstream price risk | None (own stack) | Exposed to Vapi pricing changes |
| Voice models | Hermes-managed (ElevenLabs, Cartesia) | Vapi model roster |
| Latency (p50 typical) | ~700ms | ~700-900ms (Vapi-dependent) |
| Agency-specific features | White-label, campaigns, multi-tenant billing | White-label branding, limited billing tools |
| Support tier | Email (Starter), priority (Agency+) | Email/community |
Best for Stammer: testing the market with a low entry cost
Stammer is a reasonable starting point for an agency operator who wants to launch a first AI voice offering without a large upfront commitment. The entry price is accessible, the white-label layer handles basic branding for 1 to 3 clients, and the Vapi-backed infrastructure is capable. If you are in the exploration phase, testing whether local service businesses in your market will pay for AI voice, Stammer lets you run that test without overcommitting to a platform. The risks become real at 5 or more clients: upstream Vapi pricing exposure, no native CRM, and limited outbound campaign capability start to constrain what you can sell.
Best for Hermes: agencies building a durable, multi-client practice
Hermes is built for agency operators who are running or plan to run 5 or more active clients and want a platform whose economics, features, and roadmap are aligned with their needs, not with a third-party infrastructure provider's. The included minutes across plans (300 on Starter, 1,000 on Business, 2,000 on Agency) give predictable monthly costs. The native CRM per workspace means you do not need a separate GoHighLevel subscription to manage client contacts and outbound campaigns. The campaign engine runs systematic outbound sequences without external automation tools. And the pricing is not subject to Vapi's pricing decisions, which have already caused disruption across the wrapper-layer ecosystem in 2026.
The infrastructure ownership question
The most consequential difference between Hermes and Stammer for a long-term agency business is not a feature on a comparison table. It is infrastructure ownership. A wrapper platform inherits its upstream provider's risk. When Vapi changes API pricing, changes rate limits, has an outage, or makes a product decision that affects resellers, every Stammer operator experiences the downstream effect. Hermes owns its voice infrastructure. When we set pricing, it stays set until we change it, for reasons that are entirely internal and disclosed to our customers in advance. For an agency that has signed 12-month retainer contracts with clients at a fixed margin, that distinction is the difference between a stable business model and a fragile one.
See our Stammer vs Assistable comparison for more context on the wrapper ecosystem, and our Vapi vs Retell comparison for the underlying infrastructure layer analysis.
FAQ
What is Stammer and how does it relate to Vapi?
Stammer is a white-label AI voice platform that sits on top of Vapi's infrastructure. It gives agency operators a branded dashboard to resell AI voice services to their clients under a custom domain and brand. The fundamental architecture is a wrapper: Stammer licenses access to Vapi's voice API infrastructure and re-packages it with a reseller layer on top. This means agencies using Stammer are one layer removed from the actual call infrastructure, and their economics and feature roadmap are tightly coupled to Vapi's decisions. When Vapi changes pricing, changes API contracts, or adds latency, Stammer users feel it. Hermes takes a different approach: it runs its own voice infrastructure stack and sells access to agency operators directly, with no upstream wrapper dependency.
How does Hermes pricing compare to Stammer for an agency running 10 clients?
Stammer's published pricing starts around $97 per month on its lowest tier and steps up based on usage and reseller limits. The catch is that Stammer passes through Vapi's per-minute costs with a markup. An agency running 10 clients with 150 to 200 minutes each per month is generating 1,500 to 2,000 minutes of monthly call volume. On Stammer, those minutes flow through Vapi at published rates (roughly $0.05 to $0.11 per minute for the raw API, plus Stammer's margin). The all-in cost depends heavily on Vapi's rate for that account tier. On Hermes at the Business plan ($399/month, 1,000 included minutes), the agency gets 1,000 minutes included and pays $0.24 per minute on overage for the remaining 500 to 1,000 minutes. For most 10-client agency portfolios, the total Hermes cost lands at $519 to $639 per month all-in with known, stable pricing. The Stammer total depends on Vapi's pricing at the time.
Does Stammer have a native CRM and campaign engine?
As of mid-2026, Stammer does not include a native CRM with per-client contact management or a campaign engine for outbound voice sequences. It provides a white-label interface for managing AI agents and a dashboard for clients to view call logs and analytics. For agencies that want to run proactive outbound campaigns (appointment reminders, recall campaigns, win-back sequences) alongside inbound call handling, that capability needs to be built externally in a tool like GoHighLevel and wired to Stammer via webhook. Hermes includes both a native CRM (per workspace, isolated per client) and a campaign engine (for outbound voice campaigns) as first-class platform features. For agencies whose value proposition includes outbound capabilities, that difference is structural.
What is the upstream pricing risk difference between Hermes and Stammer?
This is the most important structural difference for agency operators thinking about platform risk. Stammer is a Vapi wrapper. In early 2026, the AI voice infrastructure market saw multiple wrapper-layer platforms experience sudden pricing changes when their underlying infrastructure providers adjusted rates. Voicerr, a similar wrapper-model platform, increased prices 7 to 10x in a single month, forcing agencies to rapidly migrate clients or absorb the cost. Because Stammer passes Vapi costs through to operators, any Vapi pricing action directly affects Stammer's economics. Hermes owns its voice infrastructure stack, which means platform pricing is set by Hermes and not subject to upstream API renegotiation. For agency operators building a long-term business, that pricing stability is a core platform selection criterion.
When does Stammer make more sense than Hermes?
Stammer is a reasonable starting point for an agency operator who wants to deploy a first AI voice product quickly and is not yet running more than 3 to 5 clients. The onboarding experience is accessible, the white-label layer works for basic branding, and the entry price is low. If you are testing the market or building your first client before committing to a more capable platform, Stammer is a usable starting block. The limitations become visible when you grow past 5 clients, need per-client billing transparency, want to run outbound campaigns without a separate GHL subscription, or need pricing that cannot be disrupted by Vapi rate changes. At that point, the migration to Hermes becomes straightforward: we provide migration documentation and can import existing agent configurations.
Outgrew Stammer? Hermes is the next step.
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