The short answer
There is no single best AI sales agent platform, so this page deliberately does not rank anything — it maps ten vendors against eight buying axes. Deployment model, channels, who owns the conversation logic, self-serve availability, packaging model, published compliance posture, private deployment, and what the buyer must supply. Every cell comes from the vendor’s own site or docs, checked on 28 August 2026, or reads not published.
How this differs from our ranked lists
We already publish three ordered lists, and if you want a recommendation you should read one of those instead: best AI sales agent platforms for full-funnel autonomous agents, best AI appointment setting software for booking meetings specifically, and best AI voice agents for outbound calls for phone-first tooling.
Those lists put a number next to each vendor, which is useful when you want an opinion and unhelpful when you want to check a constraint. A ranking collapses eight independent variables into one, and the collapsing function is always the author’s, including ours.
This page does the opposite. Same market, no ordering. The value is the axes: which questions actually separate these products, and what each vendor says publicly about each one. Read down a column when you have a hard requirement, such as on-premises deployment. Read across a row when you are shortlisting.
How we sourced this
Methodology. On 28 August 2026 we opened each vendor’s own website, pricing page and public documentation, and recorded what was stated there. Specifically:
- What this is: a record of vendor-published information. It is not independent testing, benchmarking or a product trial. We did not run calls on these platforms for this article.
- What we excluded: affiliate roundup blogs and comparison-site listings. Those pages are frequently stale or wrong, and their incentives are not the reader’s. If a claim was not on the vendor’s own property, it is not in the table.
- Disclosure: Zian AI publishes this comparison and is one of the ten entries. Zian’s row is held to the same standard as every other, which is why it carries the most not published cells of any vendor here.
- What is not compared: latency, transcription accuracy, answer quality and conversion lift. No vendor in this set publishes a reproducible methodology for those numbers, so any table comparing them would be comparing marketing claims measured under undisclosed conditions. We would rather leave the column out than fake it.
- Freshness: pricing pages and feature pages in this category change monthly. Treat every cell as a snapshot with a date on it, and verify anything load-bearing before you sign.
Axis 1-3: build model, control and channels
The first real fork is who writes the conversation logic. On a developer platform you do — the vendor supplies the runtime, the telephony plumbing and the model access, and the behaviour of the agent is your codebase. On a managed service, the vendor owns it, and you supply the offer and the data. Neither is better; they fail differently. We have written about that trade-off in more depth in build versus buy for AI agents.
| Platform | Deployment model | Who owns the conversation logic | Channels the vendor publishes |
|---|---|---|---|
| Zian AI | Managed service; agents configured and operated by Zian | Zian, via SmartReach AI and PrecisionPitch AI | Voice, SMS, email, WhatsApp |
| Synthflow | No-code visual flow designer plus API, sold through a sales motion | Buyer | Voice, chat and SMS on the site; WhatsApp Business Calling (inbound voice inside WhatsApp Business) in the docs |
| Retell AI | Developer platform with pre-built agent templates | Buyer | Voice, SMS, chat |
| Vapi | Developer API first | Buyer | Voice, SMS, chat |
| Bland AI | Pathway builder plus API | Buyer | Voice; SMS and web chat; iMessage on higher tiers |
| ElevenLabs Agents | No-code configuration plus SDKs and REST/WebSocket APIs | Buyer | Telephony, web, mobile, WhatsApp, SMS, email, chat |
| Thoughtly | No-code workflows plus REST API, sold through demo | Buyer | Voice, SMS, email |
| 11x | Managed digital workers (Alice for outbound, Julian for inbound phone) | 11x | Email, LinkedIn, phone, SMS |
| AiSDR | Managed SaaS; buyer connects mailboxes and CRM | AiSDR, with buyer configuration | Email, LinkedIn, phone via an Aircall integration |
| PolyAI | Two documented paths: an agent builder for non-technical teams, an agent development kit for developers | Buyer | Voice is what the site foregrounds; other channels not detailed |
Note the channel column carefully. Voice-native platforms have converged on adding SMS and chat, but full multi-channel orchestration across email and messaging is still the minority position. If your motion is a call followed by a text followed by an email three days later, most of this list requires you to assemble that yourself from a voice runtime plus your own sequencing layer.
Axis 4-6: how you buy, and what you bring
Self-serve availability is the axis buyers underrate. It determines whether you can evaluate the thing this afternoon or whether evaluation is a procurement project. It also correlates with nothing about quality — several of the strongest enterprise products here will not let you touch them without a call.
We give no dollar figures anywhere on this page, deliberately. Prices in this category move faster than we can maintain a table, and a stale number is worse than none. The packaging model is the durable fact.
| Platform | Self-serve signup | Packaging model (qualitative) | What the buyer supplies |
|---|---|---|---|
| Zian AI | No. Waitlist beta, no free trial, no self-serve signup | Not published during beta | The offer, the contact data and CRM access; Zian builds and runs the agents |
| Synthflow | Mixed signals: the homepage offers free agent building from templates, but the pricing page presents annual enterprise contracts and the primary calls to action are demo and sales | Annual enterprise contract, scoped on call volume, concurrency, telephony, integrations, security needs and launch support | Telephony setup and integrations, per the vendor’s own scoping list |
| Retell AI | Yes. Free starting credits, stated as no commitment | Usage-based: per minute for voice, per message for chat; custom enterprise pricing with volume discounts | Telephony (Twilio, Telnyx or custom), prompts, integrations |
| Vapi | Yes. Dashboard signup with included minutes on the entry tier | Usage per minute and per message on the build tier; fixed platform fee plus committed volume on the scale tier; model provider costs passed through, or bring your own API key | Application code, telephony, optionally your own model keys |
| Bland AI | Yes. Entry tier with credits and an inbound number, no card required | Per-minute usage plus a monthly platform fee that varies by tier; enterprise contracted to volume | Pathways and integrations |
| ElevenLabs Agents | Yes. Free tier with included minutes and a commercial licence | Usage-based, with a separate enterprise tier that adds forward-deployed engineering | Prompts, knowledge base, integrations |
| Thoughtly | No self-serve path published. Every plan’s call to action is sales-led — talk to sales, get a quote, talk to enterprise. The pricing page’s own FAQ lists “Do you offer a pilot or trial?” without publishing an answer, so trial availability is not published | Monthly subscription tiers with usage allowances; overage billed in arrears | Not published |
| 11x | No. Demo-led throughout | Not published | Not published |
| AiSDR | Yes. A month-to-month entry plan; higher tiers move to quarterly contracts | Subscription priced on monthly contact volume rather than per seat; unlimited users on higher tiers | Existing email and CRM accounts; AiSDR handles mailbox creation, domain setup and warmup |
| PolyAI | Partial. A start-building path into the agent studio sits alongside request-a-demo | Not published | Not published |
Four not published cells in one column is not a failure of research. It is the finding. Enterprise-led vendors in this category treat packaging as a negotiation input, and any comparison table that fills those cells with confident numbers has either sourced them from a reseller blog or invented them.
Axis 7-8: published security posture and private deployment
This is where reading the vendor’s own page matters most, because certification claims get flattened badly in secondary coverage. Two distinctions to hold onto. First, a certification held by a vendor is not the same as a certification held by the cloud that vendor runs on. Second, an attestation available on request at an enterprise tier is not the same as one that covers your account by default.
| Platform | Published compliance and security posture | Private, dedicated or self-hosted deployment |
|---|---|---|
| Zian AI | No certification of its own. Zian holds no SOC 2, ISO 27001, ISO 27017 or ISO 27018 certification. Zian’s published security page states those certifications “are held by the infrastructure and AI providers that power Zian AI” and that “we do not claim these certifications in Zian AI’s own name”. The same page states Zian’s “internal practices are modelled on the principles of ISO/IEC 27001”, that data in transit is protected by TLS 1.3 or higher and data at rest by AES-256, that machines are hosted in the USA, Australia and Europe, and that it addresses UK GDPR, EU GDPR and the Australian Privacy Act 1988. No independent attestation of Zian’s own controls is published | Yes. Private model deployment on customer infrastructure |
| Synthflow | SOC 2, GDPR, HIPAA and ISO 27001 badges on the pricing page, plus EU and US hosting options | Not published; the documentation describes a cloud platform. Regional hosting choice is offered, which is data residency rather than self-hosting |
| Retell AI | SOC 2 certified and HIPAA-ready, with business associate agreements and data processing agreements available for enterprise | A dedicated server option on the enterprise plan; shared infrastructure below that |
| Vapi | SOC 2, HIPAA, PCI, SSO and RBAC listed against the scale tier; HIPAA and zero data retention are sold as paid add-ons rather than being standard | Not published on either the pricing or enterprise page |
| Bland AI | SOC 2 Type I and Type II, HIPAA-eligible with a signed BAA, GDPR and PCI DSS | Yes. On-premises and VPC deployment on enterprise, plus a dedicated orchestration server |
| ElevenLabs Agents | SOC 2 Type II, ISO 27001 and PCI DSS Level 1, with HIPAA and GDPR compliance; zero retention mode and regional data residency on enterprise | On-premises options referenced for enterprise customers, without published detail |
| Thoughtly | SOC 2 Type II reports marked “on request” at the scale tier and included at enterprise; TCPA and state DNC compliance review from the scale tier; HIPAA with BAA and PCI scope review at enterprise only | Dedicated infrastructure and data residency at enterprise, plus bring-your-own-model |
| 11x | SOC 2 Type 2 and CASA, with end-to-end encryption | Not published |
| AiSDR | A SOC 2 Type II badge image in the homepage badge strip, and a trust centre at trust.aisdr.com. There is no security page — aisdr.com/security returned 404 on 28 August 2026 — and no scope, period or report availability is published anywhere we could reach | Not published |
| PolyAI | SOC 2, HIPAA, GDPR and PCI DSS, described as standard | Not published |
If data residency or on-premises operation is a hard requirement, this column shortens your list to a handful of vendors immediately, and it is worth confirming before you evaluate anything else. Our own take on when that requirement is real and when it is procurement theatre is in private AI deployment for sales agents.
Sources: every page we opened
Each cell above traces to one of these vendor-owned pages, opened on 28 August 2026. Nothing in the tables comes from a roundup, a review site or a reseller.
- Zian AI: zian.ai and the security and privacy whitepaper
- Synthflow: synthflow.ai, pricing and docs
- Retell AI: pricing
- Vapi: pricing and enterprise
- Bland AI: pricing
- ElevenLabs Agents: elevenlabs.io/agents
- Thoughtly: pricing
- 11x: 11x.ai
- AiSDR: aisdr.com, pricing and trust centre. Note that aisdr.com/security returned 404 when we checked
- PolyAI: poly.ai
How to use this matrix without misreading it
Three cautions.
Not published means not published. It does not mean the vendor lacks the capability. It means a buyer performing ordinary diligence cannot confirm it from public material, which is itself a procurement fact worth knowing before you build a business case on an assumption.
Badges are not reports. A logo on a pricing page tells you a vendor has been through an audit. It does not tell you the scope, the period, the exceptions, or whether the system you are buying was in scope. Ask for the report. Our voice AI vendor security questionnaire covers what to ask for and in what order.
Choose against us where the axes say so. If you have engineers and want the conversation logic in your own repository, a developer platform — Vapi, Retell AI or Bland AI — is the right answer and Zian is the wrong one. If you need to evaluate something this afternoon without a sales call, Zian cannot help you at all; Retell AI, Vapi, Bland AI and ElevenLabs Agents all publish a self-serve entry path. If you need a vendor’s own SOC 2 report rather than an inherited one, every other vendor in this table is ahead of us on that axis today.
Capability is not fit. A row full of green does not mean a platform will work for your motion, your regulator or your team’s technical depth. The matrix narrows a field; it does not pick a winner. That is what a pilot is for.
Where Zian AI sits
Plainly: Zian AI is in waitlist beta. There is no self-serve signup, no free trial and no published pricing. Zian is a managed service rather than a build-your-own platform, which suits teams that want an outcome and rules out teams that want to own the conversation logic themselves. It runs voice, SMS, email and WhatsApp under one orchestration layer, and it supports private model deployment on customer infrastructure.
The figures Zian publishes are its own operating results: 50,769+ qualified sales appointments set, a 2,736% increase in lead contact rates, 3,102% more sales appointments and 28x more contact attempts. Zian has been running outbound acquisition since 2017, with a learning engine tracking around 420,000 data points across more than 10,000 leads a day. Those are Zian’s numbers about Zian’s own history. They are not category benchmarks, and they are deliberately absent from the tables above, because nothing comparable is published by the other nine vendors.
Frequently asked questions
Why doesn’t this comparison rank the platforms?
Because ranking requires weighting, and the correct weighting depends on your constraints, not ours. A developer platform is the right answer for a team with engineers and the wrong answer for a four-person sales team, and no ordering can be true for both. If you want an opinionated order, we publish one in our ranked list of AI sales agent platforms, where the weighting is stated openly.
Why are there no prices in this table?
Two reasons. Prices in this category change frequently enough that a published table is misleading within a quarter, and several vendors here publish no pricing at all. The packaging model — usage per minute, monthly platform fee, subscription by contact volume, annual enterprise contract — is the stable fact and the one that actually shapes your cost curve as you scale.
What does “not published” mean in the cells?
It means we opened the vendor’s own site, pricing page and documentation on 28 August 2026 and could not find the information stated there. It is not a judgement about the product. A vendor may well offer the capability under NDA or in a sales conversation. We chose to record honest gaps rather than fill them from third-party roundups, which are the least reliable source in this category.
Does a vendor’s SOC 2 certification mean my AI calling program is compliant?
No. SOC 2 is an examination of a service organisation’s controls, not a licence for how you use the service. According to AICPA and CIMA, the 2017 Trust Services Criteria (with revised points of focus, 2022) “presents control criteria established by the AICPA’s Assurance Services Executive Committee (ASEC) for use in attestation or consulting engagements to evaluate and report on controls over the security, availability, processing integrity, confidentiality, or privacy of information and systems used to provide products or services …”. The sentence continues by listing the entity levels the criteria can be applied at. Nothing in that scope covers your consent records, your calling hours, your disclosure wording or your suppression lists. Those obligations stay with you regardless of which platform you buy.
Which platforms let me run the models on my own infrastructure?
From published material as at 28 August 2026: Bland AI documents on-premises and VPC deployment on enterprise plans, ElevenLabs references on-premises options for enterprise without detail, Thoughtly offers dedicated infrastructure with data residency and bring-your-own-model at enterprise, Retell AI offers a dedicated server on enterprise, and Zian AI offers private model deployment on customer infrastructure. Dedicated infrastructure and true self-hosting are not the same thing, so confirm which one a vendor means before you treat the requirement as satisfied.
Why isn’t latency, accuracy or conversion compared?
Because none of these vendors publishes a reproducible methodology for those measurements. Latency figures depend on model choice, telephony route, region, concurrency and how the vendor defines the start and end of the interval. Without a stated method, two numbers are not comparable even when both are honest. A table of them would look rigorous and mean nothing.
Can I sign up for Zian AI today?
No. Zian is in waitlist beta with no self-serve signup and no published pricing. Access is through a partnership application, and the honest version of that answer belongs in a comparison table just as much as any competitor’s gap does.
Next step
If the axes above point you toward a managed, multi-channel agent rather than a platform you assemble yourself, and private deployment on your own infrastructure is on your requirements list, Zian AI is worth a conversation. There is no trial to start and no price to quote yet, so the only honest next step is a direct one. Apply For Partnership and we will tell you plainly whether the fit is there.