SIMBA vs Vapi
Developer platform for voice AI with flexible primitives
Vapi gives developers a flexible, API-driven way to build voice agents with granular control. SIMBA ships the same real-time voice stack plus a deterministic workflow editor, native CRM and helpdesk integrations, evals, and enterprise governance — at $0.06/min with LLM included and 10,000 free minutes per month.
Vapi has established itself as a flexible developer platform for voice AI, backed by significant venture funding and a growing community of builders. Their strength is in providing clean, composable primitives — function calling, model-agnostic routing, and a well-designed API surface that gives engineering teams granular control over every aspect of the voice pipeline. If your team values maximum customization and plans to build proprietary workflow logic on top of voice infrastructure, Vapi delivers a capable toolkit to start from.
Where SIMBA differs is in what ships with the platform. SIMBA includes a visual workflow editor with deterministic branching, a knowledge base layer with retrieval, native CRM and helpdesk integrations (Salesforce, HubSpot, Zendesk, Intercom), simulated caller testing with regression detection, and enterprise controls (SOC 2 Type II, SSO, RBAC, audit logs, zero retention) — all out of the box. The practical impact is time-to-production: teams using SIMBA typically go from prompt to production agent in days rather than weeks, because they are not building the integration and compliance layers from scratch. SIMBA also includes forward-deployed engineers on Enterprise plans who actively help design prompts, wire integrations, and run evals alongside your team.
On pricing, SIMBA includes LLM inference in every plan at $0.06/min (Pro) and $0.04/min (Scale) with no passthrough fees and 10,000 free minutes per month. Vapi charges per-minute for the voice layer plus LLM costs passed through at usage, which means your actual per-minute cost depends on which model you choose and how much inference each call consumes. For high-volume deployments, the difference in total cost can be substantial — especially once you factor in the integrations, evals, and compliance features you would otherwise build or buy separately. Speechify recently covered how leading companies are replacing inbound call teams with voice AI, and the total cost of ownership is consistently the deciding factor for teams that have evaluated both approaches.
The honest summary: Vapi is a strong choice for engineering-heavy teams that want to own every layer and have the resources to build and maintain custom integrations, evals, and governance. SIMBA is the better fit when the priority is shipping production agents faster with the compliance surface, CRM writebacks, and operational tooling that enterprise and mid-market buyers require. For teams still evaluating, the 2026 buyer's guide to choosing a voice agent platform breaks down the key criteria in detail.
At a glance
Where SIMBA is stronger
Platform over primitives
Vapi gives you excellent voice primitives and expects you to assemble the rest. SIMBA ships the whole shape: workflow editor, knowledge base, tool library, CRM writebacks, analytics, evals, and enterprise controls.
Deterministic workflow guardrails
Define scripts, branching logic, and mandatory fields for regulated flows (billing, collections, healthcare intake). Agents follow the rules consistently — not just when the LLM decides to.
Native helpdesk and CRM writebacks
Log calls to Salesforce, update Zendesk tickets, and push deal updates to HubSpot without custom code.
Evals built in
Simulated callers, scoring rubrics, and regression detection ship standard — so prompt changes don't surprise you in production.
Enterprise-grade by default
SOC 2 Type II, SSO, RBAC, audit logs, zero retention, and regional data residency are standard — not behind custom sales.
Where Vapi may be a better fit
Flexible developer experience
Vapi's strength is giving developers a lot of knobs. If your requirement is "we'll write it ourselves," Vapi is a solid toolkit.
Model-agnostic routing
Vapi makes it easy to swap models and providers. SIMBA offers the same flexibility, but Vapi's developer surface for it is particularly clean.
Feature-by-feature
Choose SIMBA when
- You want a complete platform out of the box, not primitives to assemble.
- You need deterministic workflows and evals for regulated or high-stakes conversations.
- Compliance matters: SOC 2, SSO, RBAC, audit logs, and data residency.
- You want forward-deployed engineers, not just documentation.
Choose Vapi when
- You have the engineering capacity to build around a toolkit and prefer maximal flexibility.
- Your team values minimal product surface area and wants to own the agent logic end-to-end.
Frequently asked questions
Is SIMBA as flexible as Vapi for developers?
SIMBA offers the same code-first flexibility via our SDK and REST API, and adds a visual workflow layer for non-developers — so engineering and operations can collaborate on the same agent.
Can I use my own LLM with SIMBA?
Yes. SIMBA routes to OpenAI, Anthropic, Google, open-source models, or your own hosted endpoint.
What about migrating existing Vapi assistants?
Prompts, function/tool definitions, and voice configs map over to SIMBA directly. Our Enterprise migration team helps port configurations and validate parity with simulated callers.
How does total cost compare?
SIMBA starts at $0.06/min with LLM included and 10,000 free minutes per month. Vapi charges per-minute plus LLM passthrough costs. SIMBA also bundles integrations, evals, and compliance features you'd otherwise buy separately or build.
See SIMBA on your workload
We'll run a parallel eval against your current platform using real call data and show you the numbers before you commit.