Comparison

Open vs. Retell AI

Retell AI is voice AI infrastructure; Open is a voice AI product. Pick based on whether you want to build the agent or configure one.

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Open positioning
Product
Retell positioning
Platform
Open time-to-prod
Days
Typical platform build
Quarters

01 — Overview

How do I choose between Retell AI and Open?

By asking what your team wants to own. Retell gives you a clean, well-engineered platform for voice AI infrastructure — you build the agent on top. Open gives you the agent — you configure its role, knowledge, and tools.

Retell AI has built one of the cleaner voice AI platforms on the market. Their LLM-agnostic architecture, clean SDK, and good documentation make them an attractive choice for engineering teams. They handle the call infrastructure (SIP via Twilio or BYO, LLM orchestration, TTS/STT) and expose them through a developer API that's pleasant to work with.

Open is in a different lane. Open is the agent itself — productized, with the carrier integrations (37+), tool integrations (~50), observability (recording, transcripts, reasoning traces, outcome tags), warm transfers, PII redaction, and compliance (SOC 2 / GDPR / HIPAA / PCI) already wired. Time-to-production is days, not quarters, because you don't build the platform.

The right choice tracks with the team. If voice AI is your product (you're building a vertical voice AI for legal intake, real estate, insurance), Retell or similar primitives let you customize every layer. If voice AI is a feature you need on your existing phone system (you run a service business, a call center, a sales org), Open ships with the integrations and compliance work that platform builders skip.

Both stacks run sub-200ms median latency in US/EU regions. Both support multilingual conversation. Pricing differs in shape: Retell charges per minute (transparent, layered), Open charges per resolved conversation (predictable per-call cost). Carrier minutes stay invoiced by your carrier in both cases.

Migration from Retell to Open is mostly about rebuilding prompts and flow logic in Open's configuration. The platform-level work (carrier integration, CRM tools, compliance) doesn't carry over because Open ships with it.

Retell is strong at

  • LLM-agnostic platform

    Bring your own LLM, swap models freely, run custom training pipelines.

  • Developer-first SDK

    Programmatic agent management with detailed control over every layer.

  • Per-minute pricing

    Transparent layer-by-layer cost.

  • Lower-level control

    Audio pipeline, latency tuning, prompt context — all exposed.

Open ships with

  • Carrier integrations done

    37+ carriers as first-class SIP destinations. No carrier-side engineering.

  • Tool integrations done

    ~50 native integrations (Salesforce, HubSpot, Zendesk, Stripe, Calendar, Shopify, Slack, Jira). Zero SDK plumbing.

  • Observability and compliance done

    Recording, redaction, reasoning traces, SOC 2 / HIPAA / PCI — included.

  • Per-resolution pricing

    Predictable per-call cost. Carrier minutes stay billed by your carrier.

02 — Why it works

What makes Open the right answer for Open vs. Retell AI

  • Faster to production for business teams

    Days to live on your existing carrier + CRM, not quarters of platform engineering.

  • More flexibility for platform teams

    Retell is a stronger primitive when voice AI is the product you ship.

  • Latency is comparable

    Both run sub-200ms median first-token latency in US/EU regions.

  • Pricing aligns with positioning

    Retell: per-minute, layered. Open: per resolved conversation, predictable.

03 — Security

Encrypted, audited, refundable

SIP over TLS for signaling, SRTP for media. Every call logged with full reasoning traces. SOC 2 Type II, GDPR-aligned, HIPAA- and PCI-ready. Backed by the Open $2M Refund Guarantee.

04 — FAQ

Open vs. Retell AI questions, answered

Yes. The work is reproducing prompts, flow logic, and tool definitions in Open's configuration. The carrier and CRM integrations Open ships save weeks of work.

Yes on enterprise plans. Voice cloning via ElevenLabs, custom voices, and BYO models are supported.

Both products run on compliant infrastructure. Open ships with SOC 2 Type II, BAA-ready HIPAA configuration, and PCI-readiness as standard. Retell offers similar compliance configurations on their enterprise plans.

Yes — common pattern is Retell for experimental or vertical-specific agents and Open for production business agents tied to the rest of the stack.

500+ concurrent calls per agent in Open is standard. Higher capacity is available on enterprise plans.

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