Kallflow LogoKallflow
New: On-Premise Voice Engine 2.0

Master every voice interaction
with absolute control.

The platform that combines the depth of custom infrastructure with the simplicity of a modern tool. Access high-level business metrics and technical data to optimize your agents while maintaining full control over privacy and providers.

TRUSTED BY GROWING TEAMS

Why Self-Host

We provide the tools, you hold the keys. Full control, security, and performance that cloud APIs can't match.

No Vendor Lock-in

Your data and configuration are yours. Export whenever you want. Agent code is also exportable; some parts may require adjustments outside Kallflow.

Local Models Coming Soon

AI & Model Control

Choose providers or use local models. Audio stays in your infra if you want.

Predictable Costs

No per-minute surprises. Cost scales with your infrastructure, not usage.

Controlled Latency

Deploy close to your users. No hops to external APIs.

Zero External Uptime Dependency

Your SLA is your SLA. You don't depend on third parties to operate.

Deployment Customization

Adapt network, security, scaling, and redundancy to your needs.

No vendor lock-in. Latency tuned for real-time voice. Designed for compliance-focused environments.

Built for Every Scale

Whether you're an agency, carrier, or software platform, Kallflow adapts to your needs.

Build & Resell Voice Agents

Launch a white-label voice AI agency in days, not months. Maintain full control over pricing and client data.

  • White-label dashboard & branding
  • Team roles & permissions
  • Global webhooks for call lifecycle events
View Agency Pricing
Acme Agency
Live
Active Calls
24
+12%
Agents
156
+8%
This Month
12.4k
+23%
Sub-accounts
3 active
TechStart Inc
45 agents2.1k calls
Global Sales Co
78 agents5.8k calls
Support Plus
33 agents4.5k calls

Product highlights

A focused set of primitives to build, deploy, and scale.

Visual Callflows

Design complex conversation logic with a drag-and-drop builder. Route calls, guide agents, and trigger external APIs.

No-Code
Logic
Routing

Global Webhooks + API

Receive real-time events for every call state change. Control calls programmatically via REST API.

REST
Webhooks
Events

Performance Hub

Monitor latency and agent performance. Drill down into individual call traces for debugging.

Analytics
Traces
Debugging

Audit Logs

Fine-grained permissions for teams plus a complete audit trail of platform and API actions—useful for governance and retention policies.

Permissions
Audit
Governance

Voice + SIP Stack

Connect your SIP provider directly. Bring numbers, trunks, and routing—while you keep control of media paths and storage.

SIP
PSTN
Voice

Client Portal + Billing

Track usage and costs per department or client. Offer a white-label portal and apply custom markups to control your margins.

Portal
Costs
Markup
Deployment

Deploy voice agents
in 3 steps

SIP trunk connected
DID attached
Carrier trunk
sip.acme.tel
TLS/SRTP · OK
Kallflow
Numbers routing
+34…0101 → agent:sales
01

Connect SIP / numbers

Bring your own carrier or SIP trunk, attach numbers, and route calls to agents.

Callflow Builder·draft
Agent
Tools · policy
Action
Create CRM ticket
02

Configure agents + callflows

Define behaviors, tools, and callflows—then assign agents to numbers or routes.

API
Webhook
Endpoint
POST https://acme.dev/webhooks/kallflow
call.startedcall.ended
Payload
{
  "event": "call.ended",
  "call_id": "c_7f3…",
  "duration_s": 128
}
03

Integrate via API + global webhooks

Integrate with your stack using the API and receive events via global webhooks.

Self-hosted pricing

No trials. Clear capacity limits for slots and billable concurrency.

Plans
Starter
Small projects / freelancers
€49 / month
Builder
Solo dev / small team
€149 / month
Agency
Internal teams for agencies
€379 / month
Enterprise
Telcos, resellers, large orgs
Custom pricing
Included agent slots31535100 (base)
Billable concurrency limit52550No limit (purchase extra capacity)
Additional slots / packsNoBuilder+ expansion (+5 slots)Agency+ expansion (+15 slots and C_bill from 50 to 80)Custom pricing
Seats115Custom pricing
CallflowsYesYesYesYes
APIBasicBasicFullFull
Global webhooksNoNoYesYes (Custom pricing)
User audit logsNoNoBasicCustom pricing (Enterprise)
White-label Customer PortalNoNoYesCustom pricing
Support / SLAEmailEmailPriorityStandard / Priority / 12x7

Enterprise Scale & Compliance

A focused Enterprise package for governance, integrations, and dedicated support—without bloating the landing.

  • Log and event export to your stack: on demand
  • Event streaming: on demand

Scale without limits

No caps on agent slots or concurrency. Add capacity as you grow with dedicated support, custom SLA, and an onboarding team that helps you succeed from day one.

Self-hosted FAQ

Questions? Answers.

The most common questions about Kallflow Self-hosted.

What does "self-hosted" mean for data/privacy?
Kallflow runs in your infrastructure. You control where call media, logs, and any stored artifacts live, how long they're retained, and who can access them.
What server requirements do I need to host Kallflow?
As a minimum recommendation, you need 8 GB of RAM and 80 GB of disk space. There is no specific CPU cores requirement. Note that these are minimum requirements to get started — if you plan to create many agents or handle many concurrent calls, you'll need to scale resources proportionally.
Do you support SIP trunks and custom carriers?
Yes. You can bring your own carrier and connect SIP trunks, numbers, and routing to voice agents.
Do you support callflows?
Yes. Callflows are part of the self-hosted product and are available across Builder, Agency, and Enterprise.
What are agent slots?
Agent slots are your capacity for how many agents you can create/assign at once (your "agent catalog" limit). Each plan includes a number of slots and may allow add-on capacity packs, up to a hard cap (except Enterprise).
What is C_bill and how is it measured?
C_bill is the maximum number of simultaneous calls you can have active on your plan. But don't worry, we don't charge you for the highest instant peak—that would be unfair if you have a 1-second spike. Instead, we calculate an average every 5 minutes throughout the month, take the 95th percentile of these averages (meaning we ignore the top 5% of readings), and round up. Practical example: imagine you normally have 3-5 calls at once, but one day you have a spike of 15 calls for 2 minutes. This brief spike will likely fall within the 5% we discard, so your C_bill would be ~5, not 15. This gives you flexibility for occasional peaks without paying for capacity you don't regularly use. If your C_bill exceeds your plan's limit, you'll need to upgrade to the next plan or, on Enterprise, purchase additional capacity.
What's the difference between Starter, Builder, Agency and Enterprise?
Starter (€49/month, 3 slots, C_bill 5) is for small projects and freelancers. Builder (1 seat, up to 15 slots, C_bill 25) is for individual developers or small projects. Agency (5 seats, up to 35 slots, C_bill 50) adds white-label, global webhooks and priority support for teams reselling or managing multiple clients. The Agency+ expansion raises C_bill to 80 and adds 15 extra slots. Enterprise raises the limits (100 slots base), adds single sign-on and user management, and offers custom SLA.
Is there a free trial?
Usually no, but we can explore it. Please send us an email at contact@kallflow.com.
What happens if I stop paying?
If payment is suspended, your agents will be deactivated and stop working. However, your agents remain accessible in the configuration and you can continue modifying them. All your conversations, logs, and data remain intact and secure in your infrastructure. The only thing that gets deactivated is your agents' ability to operate. If you reactivate your subscription, your agents would become fully operational again.
How many users/seats can I have?
Starter includes 1 seat, Builder includes 1 seat, Agency includes 5 seats, and Enterprise offers custom seat allocation based on your needs.
What happens if I exceed the slot limit?
Starter, Builder and Agency have hard caps (3, 15 and 35 slots respectively). If you need more capacity, you must upgrade to the next plan or move to Enterprise (100 slots base with option to purchase more).
Can I buy additional slots?
Starter cannot purchase additional slots. Builder can activate the Builder+ expansion with 5 extra slots. Agency can activate the Agency+ expansion, which adds 15 extra slots and increases C_bill from 50 to 80. Enterprise has 100 slots base and additional capacity is purchased as needed.
Can I use my own branding (white-label)?
Builder shows "Powered by Kallflow" branding. Agency and Enterprise include full white-label capabilities with your own branding.
Which plans have global webhooks?
Global webhooks are available on Agency and Enterprise plans. Starter and Builder have per-agent webhooks and also includes webhooks at the call flow level, but the information that can be sent is limited.
What type of support does each plan include?
Starter: Email support with max 24h response. Builder: Email support with max 24h response. Agency: Priority support with max 12h response. Enterprise: Custom SLA.
Feel free to email us: contact@kallflow.com

Deploy Kallflow
in your infrastructure.

Self-hosted voice agents with SIP, callflows, API integrations, and data sovereignty by design.