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Comparison · Retell

Assistable vs Retell

Retell gives engineering teams a capable API and honest per-component pricing for building voice agents. Assistable ships the finished operation: telephony, campaigns, contacts, and QA on one platform at $0.07/min all-in.

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<500 ms latency·99.99% uptime·4.7/5 on Trustpilot

The bottom line

Assistable

Assistable is an operating platform, not a parts catalog. Telephony, contacts, campaigns, channels, and QA run on one data plane with one price: voice at $0.07/min all-in and messages at $0.02 each. You publish immutable versions, roll back with one click, and run outbound through a compliance-gated dial engine without assembling any of it.

Retell AI

Retell is a developer-first API and platform. You choose the LLM, the TTS tier, the telephony path, and the add-ons, and each is a published per-minute line item. That gives engineering teams real control, and it also means the surrounding operation, CRM actions, chat surfaces, SMS registration, and campaign hygiene, is yours to build and run.

The real comparison

Six places the platforms actually differ.

The same six questions on every comparison page. Here is how Assistable and Retell each answer them.

01 / 06

Time to first live call

From signup to an agent answering a real phone call.

Assistable

Signup builds your first assistant for you, grants $10 in usage credit, and sells you a real US or Canadian local number in-app. There is no SDK to integrate and no STT, TTS, or LLM providers to wire together, so the first live call happens in minutes, in one sitting. Full production rollouts land in 2-3 days.

Retell

Retell's self-serve path is genuinely fast: create an agent from a template, test it in a browser call, buy a number, and bind it, about 15 minutes per their docs. From there the build is componentized: the LLM, the TTS tier, and each add-on you enable is a separate priced line item, and back-office actions run through custom tools and webhooks you write.

Assistable delivers

First assistant created automatically during onboarding·$10 usage credit granted at signup, pay as you go·US and Canadian local numbers purchased in-app·Full production rollouts in 2-3 days

02 / 06

Infrastructure and telephony

What you assemble before production, and who runs it.

Assistable

Numbers, SIP, recordings, and call control run on the platform's own carrier-grade voice stack, so there is no carrier account to create and no per-component bill to reconcile. Compliance rails are built in: DNC scrubbing, honeypot detection, A2P 10DLC registration, and KYC review. Web chat, SMS, and voice share one gateway, and identity resolution maps every phone number, email, and web visitor to one contact before the agent runs.

Retell

Retell sells managed US and Canada numbers at $2/mo local and $5/mo toll-free, or you bring your own elastic SIP trunk from Twilio, Vonage, and other carriers with no Retell telephony charge. Voice infrastructure is its own $0.055/min line item. SMS runs on Twilio-backed numbers only, and A2P registration is an approval you file yourself, roughly 2-3 weeks per their docs.

Assistable delivers

TLS SIP trunk auto-provisioned per imported number, SRTP as opt-in·DNC scrubbing, honeypot detection, A2P 10DLC registration, KYC built in·Durable outbox retries from 30 seconds to 1 hour, 5 attempts default·<500 ms latency, 99.99% uptime SLA

03 / 06

Version control and rollback

How changes ship, and how fast you can undo one.

Assistable

Publishing writes an immutable numbered version to an append-only commit log while live traffic keeps executing the last published version, never the open draft. Traffic follows an explicit deploy pointer, so rollback is one click to any prior version. Branches stage bigger rewrites and merge into Main without changing the flow id, so phone numbers, endpoints, and channels never re-point. Publish is a role-based permission, and every publish and rollback is audit-logged.

Retell

Retell's versioning is real and well documented: published versions are immutable, multiple drafts can coexist, and prod and staging environment tags redeploy instantly when you move a tag. Side-by-side version comparison and a full versioning API round it out. Rollback means re-publishing a prior version as a new draft or moving a tag back.

Assistable delivers

Immutable numbered versions in an append-only commit log·Explicit deploy pointer with one-click rollback·Branches merge into Main without changing the flow id·Publish gated by role-based permission, audit-logged·Test drawer shows node, model, tokens, latency, and cost per reply

04 / 06

Call routing and transfers

What happens when a caller needs a human.

Assistable

Warm transfer is one configuration, not flow wiring: it holds the caller on hold music, dials your team in order with fallback hunting, screens each leg with answering-machine detection so voicemail never gets the call, and whispers a private briefing generated from the live transcript before bridging. Unanswered transfers can resume the AI instead of hanging up, and a per-minute sweep force-resolves stale holds. Tag rules route inbound by contact tag with priority and active hours.

Retell

Retell documents cold, warm, and agentic warm transfers, where a second AI talks to the human target and decides whether to bridge, with whisper messages, three-way announce, and human detection with a timeout. Transfer failure routes to a failure edge in your flow. When concurrency is maxed, inbound calls queue about 40 seconds, then go to a single configured fallback number or end.

Assistable delivers

Ordered fallback hunting, up to 6 dial attempts, 25-second default ring timeout·Answering-machine detection screens every transfer leg·Whisper briefing generated by the LLM from the live transcript·Connected, voicemail, no-answer, and failed each route their own branch·Tag rules with priority and active hours for time-of-day routing

05 / 06

Outbound at scale

Dialing a list without burning it.

Assistable

Campaigns are an engine, not a CSV upload. A dial engine converges every minute, tops running campaigns up to their concurrency caps, and reconciles outcomes seconds after hangup. A/B splits across assistants are built in, retries for no-answer, busy, and failed honor the calling window, and every dial passes DND, blacklist, E.164, and wallet checks, with a wallet at zero pausing the campaign instead of burning the list.

Retell

Batch Call is first-class in Retell: upload a CSV with a phone number column, extra columns become dynamic variables, then send now or schedule inside configurable time windows, at $0.005 per dial on top of the per-minute rate. A per-row agent-version override column makes manual split tests possible. Structurally, the list you upload is the campaign: enrollment, variables, and splits are columns in the CSV you prepare.

Assistable delivers

Dial engine converges every minute; claim-first updates make double-dials impossible·A/B splits must sum to 100; deficit-based assignment converges on the split·Timezone-aware windows with day-of-week selection and overnight wrap·Wallet at zero pauses the campaign with a stated reason·Enroll up to 25,000 contacts by filter, list, or CSV

06 / 06

Observability and QA

How you find out something went wrong.

Assistable

Write monitor rules in plain English and an LLM judge grades every finished call and chat, not a sample, with verdicts citing the decisive transcript moment. When a rule fires, the AI drafts a minimal prompt fix, shows a line diff, and proves it by replaying the failing conversation 3 times through the published flow, so confidence is a measured pass rate, never self-reported. There is no per-minute analysis fee; pricing carries no per-feature add-ons.

Retell

Retell's QA stack is productized: automatic post-call analysis with user-defined extraction fields, simulation testing with AI-simulated users before release, and an AI QA add-on that evaluates a sampled set of calls across hallucination, knowledge base accuracy, latency, sentiment, and tool usage. AI QA is priced at $0.10 per analyzed minute after the first 100 free.

Assistable delivers

LLM judge grades every finished call and chat, not a sample·Verdicts cite the decisive transcript moment with confidence·Fixes proven by replaying the failing conversation 3 times through the published flow·Per-rule health: fire rate, drift, silence, human-overturn rate

At a glance

Side by side

Getting live

First live call
AssistableMinutes, in one sitting
RetellAbout 15 minutes, per their docs
First agent
AssistableBuilt for you at signup
RetellCreate from a template
Included at signup
Assistable$10 credit and a free local number
Retell$10 free credits

Platform scope

Versioning with rollback
AssistableYes
RetellYes
Campaign engine
AssistableDial engine with A/B splits, retries, windows
RetellBatch Call: CSV upload, $0.005/dial
QA coverage
AssistableEvery call and chat judged
RetellSampled calls, paid add-on
Channels on one data plane
AssistableVoice, SMS, WhatsApp, chat
RetellVoice core; SMS and chat via Twilio numbers and API

Telephony

Buy numbers in-app
AssistableUS local and toll-free, by area code or city
RetellUS and Canada, $2/mo local, $5/mo toll-free
Bring your own numbers
AssistableTLS SIP trunk auto-provisioned per number
RetellElastic SIP trunking, no telephony charge
Warm transfer
AssistableYes
RetellYes

Pricing

Voice per minute
Assistable$0.07/min all-in
Retell$0.07 to $0.31/min, their published range
Platform and seat fees
AssistableNone
Retell$0 platform fee on pay as you go
Concurrency
AssistableNo per-line concurrency fees
Retell20 included, $8/mo each additional, burst surcharge $0.10/min
Messaging
AssistableMessages $0.02 each
RetellChat $0.026 to $0.052 per AI message by model

Retell AI capabilities and pricing reflect their publicly published information as of July 2026 and may change.

Why teams switch

Why teams choose Assistable.

01

Live the day you sign up

Onboarding creates your first assistant, grants $10 in calling credit, and sells you a real local number in-app. The first live call happens in minutes, and full production rollouts run 2-3 day deploys.

02

Version control for agents

Immutable numbered versions in an append-only history, an explicit deploy pointer with one-click rollback, and branches that merge without changing the flow id. Live traffic never executes an open draft.

03

Telephony that behaves like a phone system

Ordered team hunting with answering-machine detection, whisper briefings generated from the live transcript, tag rules with active hours, and DND, blacklist, and wallet gates on every outbound dial.

Under the hood

The infrastructure
most platforms rent.

We operate dedicated network, telephony, and compliance rails, and let you choose the models on top. That is what keeps conversations fast, clear, and safe at scale.

  • Edge

    Co-located edge PoPs and GPUs power low-latency voice AI globally.

  • Telephony

    A full telephony stack built in: native calling and texting without wiring a carrier.

  • Network

    Audio runs on a private global network, bypassing the public internet for call quality.

  • Compliance

    A programmatic compliance layer: DNC and honeypot detection, 10DLC and KYC, attribution reporting.

  • Models

    LLM, TTS, and STT à la carte, self-hosted or from major providers. Enterprises can bring their own keys.

  • Languages

    100+ languages and dialects, with real-time multilingual transcription and translation.

  • Coverage

    Calling and texting in 105+ countries.

Questions

Assistable vs Retell, answered.

What is the difference between Assistable and Retell?
Retell gives engineering teams a capable API and honest per-component pricing for building voice agents. Assistable ships the finished operation: telephony, campaigns, contacts, and QA on one platform at $0.07/min all-in.
Is Assistable or Retell more cost effective?
Assistable is usage-based at $0.07 per minute for voice, all-in, and $0.02 per message, with no platform fee, no seat fees, and free pay-as-you-go signup. Retell's published pricing model is per-component PAYG. Assistable bundles telephony, model, and voice into one per-minute rate, so there are no per-component add-ons to reconcile.
When should I choose Retell over Assistable?
Retell is the right call when you have an engineering team that wants API-level control of every layer. Its versioning story is genuinely strong: immutable published versions, parallel drafts, and prod and staging environment tags that redeploy the moment you move a tag. Per-component pricing lets you tune each line item, down to bringing your own SIP trunk at no Retell telephony charge, and you get LLM choice across OpenAI, Anthropic, and Gemini plus simulation testing before release. If you are building a custom voice product on top of an API, with your own chat surfaces, CRM actions, and campaign tooling around it, Retell is a solid foundation, and its enterprise tier adds SSO, dedicated servers, and on-prem options.
How fast can I get a live AI agent with Assistable?
Signup is self-serve. Onboarding creates your first assistant, grants $10 in usage credit, and lets you buy a US or Canadian local number in-app, so the first live call happens in minutes without a sales call. Full production rollouts run 2-3 days.

Fair is fair

When Retell is the right call

Retell is the right call when you have an engineering team that wants API-level control of every layer. Its versioning story is genuinely strong: immutable published versions, parallel drafts, and prod and staging environment tags that redeploy the moment you move a tag. Per-component pricing lets you tune each line item, down to bringing your own SIP trunk at no Retell telephony charge, and you get LLM choice across OpenAI, Anthropic, and Gemini plus simulation testing before release. If you are building a custom voice product on top of an API, with your own chat surfaces, CRM actions, and campaign tooling around it, Retell is a solid foundation, and its enterprise tier adds SSO, dedicated servers, and on-prem options.

Results

Take their word for it.

Real operators, verified reviews, and one 18-month evaluation that ended with 25,000 flawless calls.

Platform lifetime

m+managed conversations

Across voice, SMS, WhatsApp, and chat.

Reliability

% uptime

Production uptime, backed by SLA.

Speed

s median answer

From first ring to answered, on every channel.

Verified customer · 18-month evaluation

25,000 calls delivered flawlessly.

“After 18 months testing voice AI platforms including Bland.ai and Synthflow.ai… Assistable delivered flawlessly on over 25,000 calls in recent weeks. It checks all the boxes with built-in features that more mature platforms haven’t integrated yet.”

Maurice M.Verified customer

Backed by a Shark

“Assistable AI is redefining business efficiency.”

KHKevin HarringtonKevin HarringtonOriginal Shark, Shark Tank
Watch →
Trustpilot4.7/5 · 35 verified reviewsHighLevel4.5/5 · 126,000+ marketplace downloads
  • “I've tested a lot of AI and automation tools, and most fall apart once you try to scale. Assistable is the real deal.”
    Jamie WVerified Trustpilot review
  • “I have been using Assistable for about 10 months, and it has changed my business completely. The voice AI quality is unmatched.”
    Travis HolzemVerified Trustpilot review
  • “The conversational quality and flexibility are amazing. Top notch tech and service from the entire team.”
    Eric KnellerVerified Trustpilot review
  • “They make it so easy to get started with voice AI. The onboarding was smooth and the results were immediate.”
    Pam VinjeVerified Trustpilot review
  • “There is no better conversational AI voice bot. There are a ton of players in the market and Assistable leads.”
    Lowe SmithVerified Trustpilot review
  • “Assistable has been a game changer for my business and is way easier to use than any alternative I've tried.”
    Greg PfefferVerified Trustpilot review
  • “Assistable AI was the best decision we have made for our company in a long time. Excellent product and team.”
    Get Amplified MarketingVerified Trustpilot review
  • “Been using Assistable for several months and it has completely changed how our team handles inbound inquiries.”
    ATVerified Trustpilot review
  • “There is no better conversational AI voice bot. There are a ton of players in the market and Assistable leads.”
    Lowe SmithVerified Trustpilot review
  • “Assistable has been a game changer for my business and is way easier to use than any alternative I've tried.”
    Greg PfefferVerified Trustpilot review
  • “Assistable AI was the best decision we have made for our company in a long time. Excellent product and team.”
    Get Amplified MarketingVerified Trustpilot review
  • “Been using Assistable for several months and it has completely changed how our team handles inbound inquiries.”
    ATVerified Trustpilot review
  • “I've tested a lot of AI and automation tools, and most fall apart once you try to scale. Assistable is the real deal.”
    Jamie WVerified Trustpilot review
  • “I have been using Assistable for about 10 months, and it has changed my business completely. The voice AI quality is unmatched.”
    Travis HolzemVerified Trustpilot review
  • “The conversational quality and flexibility are amazing. Top notch tech and service from the entire team.”
    Eric KnellerVerified Trustpilot review
  • “They make it so easy to get started with voice AI. The onboarding was smooth and the results were immediate.”
    Pam VinjeVerified Trustpilot review

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