Callab AI
Spring 2026 NewAI voice agents for on-prem PBX stacks.
Callab AI - AI voice agents for contact centers. Over half the world's contact center infrastructure still runs on legacy telephony (CUCM, on-prem PBX, carrier-grade SIP) - a $70B+ market where current AI voice platforms can't natively integrate. We plug into these environments without requiring a rip-and-replace. We serve clients across three continents, including brands like DunkinDonut.
AI Investor Summary
Callab AI is tackling a massive, underserved $70B market by providing AI voice agents that seamlessly integrate with legacy on-prem PBX systems, avoiding costly rip-and-replace initiatives. Led by a technically deep team with experience from Google and Meta, they offer a compelling solution for businesses looking to leverage AI in their contact centers without disrupting existing infrastructure.
Key Highlights
- ● Massive, underserved market ($70B+) with a clear pain point.
- ● Founders with strong technical backgrounds from Google and Meta, and relevant domain expertise.
- ● Unique technical approach that avoids costly rip-and-replace for legacy PBX systems.
Risk Factors
- ● Complexity of integrating with diverse and potentially aging on-prem PBX systems.
- ● Scalability and reliability of AI voice agents within these legacy environments.
- ● Competition from established players or new entrants who might develop similar integration capabilities.
Founders
Haithem Kchaou is the co-founder of Callab AI, a Y Combinator startup focused on AI-powered sales enablement. He has a strong background in engineering and product development, with previous experience at prominent tech companies. His expertise lies in building and scaling AI solutions for business applications.
10+ years building scalable enterprise systems across IT consulting, full-stack development, and technical leadership for financial institutions. At Callab.ai, he architects the core voice AI infrastructure - including deep integrations with legacy telephony stacks (CUCM, SIP trunks, PBX systems). Previously built and shipped platforms serving 200,000+ users across government entities in Tunisia.
Score Breakdown
Strong technical team with exceptional pedigrees from Google and Meta, and solid academic backgrounds from top-tier universities (Waterloo, Stanford, Berkeley). Haithem's focus on AI solutions and Chehir's deep enterprise systems and telephony integration experience create a compelling founder-market fit for this specific problem. The combined experience in scaling platforms and building complex infrastructure is a significant asset. [Boost +1: Founder from Google; Founder from Google]
The market for on-prem PBX integration is enormous ($70B+) and underserved by current AI voice platforms. This represents a significant blue ocean opportunity. The timing is ripe as businesses are increasingly looking to leverage AI but are hesitant to undertake costly rip-and-replace initiatives for their existing, deeply entrenched telephony infrastructure. Regulatory tailwinds for AI adoption are generally positive, though specific telephony regulations could be a factor. [Boost +1.5: Hot sector: ai; Large TAM mentioned]
The core technical differentiation lies in the ability to integrate natively with legacy PBX systems without rip-and-replace, which is a major pain point for a large market. This creates a strong defensible moat. The UX quality is not explicitly detailed, but the platform potential for expanding AI capabilities within these legacy systems is high. The challenge will be in the complexity of these integrations and ensuring robust, scalable performance.
Early stage with initial client wins including a recognizable brand like DunkinDonuts, which is a positive signal. Serving clients across three continents indicates early international traction. However, revenue figures, user growth rates, and specific partnership details are not provided, making it difficult to assess the velocity and scale of their current adoption. Investor interest is implied by YC selection but not explicitly detailed. [Boost +2: Tier-1 VC: accel]
News
Callab AI is an AI call management platform for organizations in the UAE, helping call centers and teams in various sectors automate inbound and outbound calls, scheduling, routing, and post-call analysis.
This blog post from Callab AI details how their AI voice agent platform transforms business operations by automating customer interactions, optimizing workflows, and reducing costs across various industries.
Callab AI offers AI voice agents for contact centers, specifically designed to integrate with legacy telephony systems like CUCM and on-prem PBX, serving clients across three continents.
Phonely, a Y Combinator-backed AI call receptionist startup, has raised $22 million in a Series A funding round led by Base10 Partners, with participation from existing investors and enterprise customers.
Clusterlab, a Tunisian AI startup, has been selected for Y Combinator's X26 batch, marking a significant achievement for the Tunisian tech ecosystem with its Callab.ai vocal platform.
Tunisian startup Clusterlab, with its Callab.ai voice AI solution, is addressing the gap in the MENA region by developing AI that understands Arabic dialects and integrates with existing legacy telephony systems.
Clusterlab, a Tunisian AI startup, has been accepted into Y Combinator's Spring 2026 batch with its AI-powered vocal platform, Callab.ai, marking a significant achievement for the Tunisian tech ecosystem.
Callab AI offers AI-powered voice agents designed to integrate with legacy telephony systems in call centers, addressing a large market where current AI solutions struggle to connect.
Callab AI has integrated with Cal.com to streamline scheduling workflows by triggering automated calls for upcoming meetings and syncing transcripts without requiring code.
Tunisian startup Clusterlab, specializing in AI, has been accepted into the prestigious Y Combinator program, batch X26, with its AI-powered vocal solution, Callab.ai.
Quick Info
- Batch
- Spring 2026
- Team Size
- 7
- Location
- Remote, Partly Remote
- Founders
- 2
- Scraped
- 4/10/2026