Ship voice as a feature in your product
Add voice AI to your SaaS without building call infrastructure. Define one agent template, then give every customer their own number and isolated data over the API. Your engineering team stays on your core product; Nixflex runs the calls underneath. Flat $0.08 a minute, your carrier, no platform fee.
Build the voice stack, or ship your feature
Building multi-tenant call infrastructure yourself means telephony, speech, a model pipeline, call recording, per-customer isolation and usage metering, before you have shipped anything your customers can see. Buying that layer means one API call per customer and your roadmap stays yours. For most SaaS teams the maths is settled: embed a platform, ship voice in weeks, and keep engineering pointed at the product you actually sell.
Every customer becomes an isolated tenant
This is the part that matters at scale. Each of your customers gets their own number, their own call history and their own settings, and none can reach another's data. That is real multi-tenancy, not one shared account with prefixes for isolation. When your first enterprise customer sends a security questionnaire asking where each tenant's data lives, the answer is already clean.
One template, a number per customer
You do not build an agent for every customer. You build one template, the prompt, the voice and the tools, and attach a number to it for each customer you onboard. Adding a customer is a single API call to provision their number, not a new build, which is how one agent template can sit behind hundreds of live numbers at once.
It stays your product, not a resold dashboard
Because the data comes back to you and the numbers are your customers' own, voice becomes a native feature of your platform rather than a tool you resell. Your customers see your product getting smarter. There is no SDK to install first; the API is plain REST you call from any language, and typed libraries are on the roadmap.
See the Multi-tenant, White-label and Embed voice pages, or the full docs. Coming from another platform? Nixflex is a modern alternative to Retell, Vapi and Bland. Compare them →
Developer FAQ
How do I add voice to my SaaS without building call infrastructure?
You call the Nixflex API. You define one agent template, then provision a number for each of your customers through the API, and Nixflex handles the calls, speech, model and telephony underneath. Your engineering team stays on your core product instead of building a voice stack from scratch.
Is each of my customers really isolated?
Yes. Every customer of yours becomes a tenant with its own number, its own call data and its own configuration. One customer can never see the calls of another. That isolation is the difference between a real multi-tenant platform and one shared workspace held together by naming conventions, which is what fails an enterprise security review.
Do I build a separate agent for every customer?
No, and you should not. You build one agent template and attach a number per customer to it. The behaviour is defined once and reused, so onboarding a new customer is one API call to add their number, not a new build. One template can sit behind hundreds of numbers.
Can each customer have their own settings and integrations?
Yes. Integrations and settings are per number, so each customer connects their own calendar, their own webhook and their own tools without touching anyone else. The shared template defines the behaviour; the per-number layer holds the specifics for each tenant.
Does the call data come back into my product?
Yes. Every call returns a transcript, summary and sentiment by webhook or from GET /v1/calls, so you surface the activity of each tenant inside your own UI. The analytics living in your product, not a vendor dashboard, is what makes it your feature rather than a resold tool.
How does pricing work when I resell this to my customers?
You pay a flat $0.08 per minute of voice, pay-as-you-go, with no platform fee to start. Because your cost is a predictable per-minute rate rather than opaque credits, you can price your own feature on top with a margin you can actually calculate.
Can my customers keep using their own phone numbers?
Yes. Nixflex is bring-your-own-carrier, so the existing Twilio or Telnyx number a customer already has can be attached to their tenant. You are not forcing anyone to move numbers to add voice.
Add voice to your SaaS today
One template, a number per customer, all over the API. Ship it this week.