Stellar
Stellar is a no-code platform for building AI voice agents that answer the phone, qualify leads, book appointments and handle support. Built for small businesses and their agencies, it ships with 16 preloaded industry knowledge packs.
What is Stellar?
Stellar is a no-code platform for building AI voice agents, aimed at small businesses that live and die by their phone line. The site also describes it as an AI receptionist and answering service, and positions it explicitly against touch-tone IVR menus: callers talk, they do not press buttons.
Four products sit on the same engine — lead qualification, appointment booking, event confirmation and customer support — and twelve named building blocks power them: Agent Builder, Self-Learning, Pipelines, Knowledge Base, CRM Enrichment, Speed-to-Lead, Call QA, Compliance, Integrations, Contacts, Voice Widget and Analytics.
The starting point is a library of 16 preloaded industry knowledge packs, from HVAC and plumbing to dental, legal intake and veterinary. You layer your own pricing, policies, service area and FAQ on top rather than writing prompts from scratch. Content is chunked into 1,536-dimension vectors, with retrieval advertised under 200 ms. The voice layer is described as a native speech-to-speech model running in a single pass, with sub-500 ms response times and interruption handling.
Two mechanisms move the agent forward over time. Self-learning analyzes each finished call and applies changes automatically above a 0.85 confidence score, sending anything below that to a human review queue. Pipelines chain several agents together across voice, email, SMS, wait and webhook steps, carrying context from one step to the next.
Compliance is built in rather than sold separately: FCC one-to-one consent, 8am to 9pm local calling windows, AI identity disclosure, recording disclosure and a real-time do-not-call list written as calls happen. Existing numbers port on every plan, and new ones can be provisioned in the United States, the United Kingdom, Canada and Australia.
Two caveats come from the site itself. The underlying voice infrastructure is Vapi, a third party Stellar acknowledges on its own comparison page. And the headline figures shown around the product — conversion rising from 14% to 34% between day 1 and day 30, 89 bookings in a month, up to 38% fewer no-shows — are interface illustrations with no published methodology behind them. Setup is advertised at roughly ten minutes, with most teams live inside thirty.
What it does
- Answers inbound calls 24/7 and books the appointment straight into the connected calendar
- Calls every new lead back in under 60 seconds of the form being submitted
- Runs the full appointment cycle: booking, rescheduling, canceling and looking up existing slots
- Answers support questions from the knowledge base and sends the price list during the call
- Confirms event registrants on a three-touch sequence, 24 hours, 2 hours and 30 minutes before the event
- Transfers to a human, with a whispered summary played to the person taking the call
- Scores the quality of every call, suggests agent improvements, and chains agents into pipelines that carry context from step to step
When to use Stellar / When not to
A quick filter to help you decide if Stellar is the right fit.
When to use Stellar
- Small businesses whose phone line is the main sales or service channel, across the 16 verticals Stellar names: HVAC, plumbing, dental, electrical, roofing, med spas, hair and nail salons, real estate, legal intake, auto repair, cleaning, fitness, landscaping, pest control, photography and veterinary
- Sales and lead-generation teams focused on speed to lead, where a form fill is called back in under 60 seconds instead of the 47 hours the site cites as the industry average
- Agencies reselling voice agents under their own brand, using the Agency and Agency Pro tiers with pooled minutes and unlimited sub-accounts
- Teams with no developer on staff, who need an agent configured through a visual eight-tab builder rather than written in code
- Event and webinar organizers who need registrants confirmed and reminded on a three-touch sequence at 24 hours, 2 hours and 30 minutes before the session
When not to use Stellar
- Businesses serving customers in languages other than English: Stellar states that its voice agents work best in English today, with other languages still under consideration
- Companies that need phone numbers outside the United States, the United Kingdom, Canada or Australia, the only countries where Stellar provisions new numbers
- Engineering teams that want to own the voice stack themselves: Stellar positions itself above infrastructure providers such as Vapi and Retell AI, not as their equivalent
- Outbound operations without documented consent: the terms require valid TCPA consent and leave the customer as the seller of record for regulatory compliance
- Healthcare practices that need a signed BAA before they start, and anyone under 18: HIPAA is not covered self-serve, a BAA is offered only on commercial request, and the terms set a minimum age of 18
How to use Stellar
A typical end-to-end flow, from setup to results.
- Create an account and start the 14-day trial: no credit card is required, and Google sign-in is available
- Pick your vertical from the 16 industry packs and, if useful, one of the four templates: lead qualification, event confirmation, appointment booking or customer support
- Configure the agent across the builder's eight tabs, covering voice, persona, script, knowledge base, connections and settings
- Choose a voice (Maya, Leo or Aria) and a tone: Warm, Professional or Casual
- Upload your own knowledge as PDFs, documents and pages from your website, layered over the industry pack
- Connect the calendar or CRM you already use, such as Google Calendar, Cal.com, Calendly or HubSpot; the site says most integrations take under two minutes from the Settings tab
- Port your existing phone number or provision a new one in the US, UK, Canada or Australia
- Publish the agent: the site says it goes live in about ten minutes, and that most teams are fully operational within thirty
- Use the version history to review and roll back any change made to an agent
- If you have technical resources, push contacts, trigger calls and pull analytics through the REST API, API keys and outbound webhooks, all available from the Growth plan
Pros & Cons
Pros
- The 16 preloaded industry packs make the agent competent on day one, with no prompt writing required
- Genuinely no-code: the site advertises an agent live in about ten minutes, with most teams operational within thirty
- TCPA and FCC compliance is on by default rather than sold as an add-on
- Native speech-to-speech model, with sub-500 ms latency claimed and interruption handling
- Pricing is public and complete, including the per-minute overage rate on every tier, and the 14-day trial covers the full Growth plan without a credit card
- Nothing is deleted when the trial ends: the account switches to read-only and everything is restored on subscription, and number porting is included on all plans
- Unusual transparency on the supply chain and the competition: eight subprocessors named in the privacy policy, ten competitors named on the site's own comparison and alternatives pages
Cons
- No published legal identity: no company form, no postal address, no legal notice and no about page anywhere on the site, even though the governing law is that of Delaware
- The legal email addresses sit on two third-party domains — legal@, privacy@, billing@ and hello@ on stellar.ai, partners@ and press@ on usestellar.ai — while the product runs on saystellar.com, and the privacy policy itself refers to the site as stellar.ai
- Very young: the domain was registered on 25 March 2026 and the legal documents took effect on 27 March 2026, leaving no verifiable track record and no Wayback Machine capture
- SOC 2 is presented as readiness verified, which is a prepared audit and not an obtained certification; no data processing agreement is published and a BAA is offered only on commercial request
- No documented way to exclude your data from model training, and no hosting country or region is published anywhere
- English only for the voice agents, and new numbers can be provisioned in the US, UK, Canada and Australia only
- No permanently free plan for new accounts, no mobile app, no publicly accessible API documentation, and the performance figures displayed on the site carry no published methodology
Pricing & Plans
There is no permanently free plan for new accounts. The entry-level paid tier is Growth at USD 149.00 per month, followed by Pro at USD 399 per month and Scale at USD 899 per month; two agency tiers are published at USD 999 and USD 1,999 per month. Each tier includes a monthly voice-minute allowance — 200, 750 and 3,000 respectively — with overage billed per minute at USD 0.18, USD 0.14 and USD 0.11. A billed minute runs from the moment the agent connects to the end of the call; ringing, hold time and voicemail detection are not counted. A 14-day trial of the full Growth plan is available without a credit card. Annual billing is offered and stated to save up to 20%, but no annualized amount is published on the site. Payments are processed through Stripe and Polar.sh and are exclusive of taxes; subscriptions are generally non-refundable, billing disputes must be raised within 14 days, and plan or price changes carry 30 days' notice.
- 3 agents
- 200 minutes per month then USD 0.18 per additional minute
- 3 knowledge bases
- 500 contacts
- 1 pipeline
- all integrations
- pre-call CRM enrichment
- 7-day Speed-to-Lead dashboard
- everything in Growth plus 8 agents
- 750 minutes then USD 0.14 per additional minute
- 5 knowledge bases
- 5
- 000 contacts
- 5 pipelines
- QA scoring and trends
- replay-based regression tests
- everything in Pro plus 20 agents
- 3
- 000 minutes then USD 0.11 per additional minute
- unlimited knowledge bases
- contacts and pipelines
- the embeddable voice widget
- 90-day Speed-to-Lead dashboard
- unlimited retention
- 3
- 000 pooled minutes then USD 0.12 per additional minute
- 5 agents per sub-account
- unlimited sub-accounts
- 6
- 000 pooled minutes then USD 0.10 per additional minute
- 10 agents per sub-account
- unlimited sub-accounts
- Free trial — 14 days of full access to Growth with no credit card
- the account then switches to read-only until a plan is purchased
- Annual billing — available alongside the monthly tiers and stated to save up to 20%
- although no annualized price is published
Data, GDPR & hosting
A consolidated view of how Stellar handles your data.
GDPR overview
Stellar's FAQ answers a plain “Yes” to the question of GDPR compliance, and the privacy policy dated 27 March 2026 backs it with configurable retention policies, data export, deletion and a schedulable purge of recordings and transcripts. Section 6 grants rights of access, correction, deletion, portability and opt-out from marketing, with additional rights acknowledged for GDPR (EEA/UK) and CCPA/CPRA (California) residents; requests go to privacy@stellar.ai. What is missing matters as much: no Article 27 EU representative is designated, no data protection officer is named, no data processing agreement is published or offered anywhere on the site, and no international transfer mechanism — standard contractual clauses or the Data Privacy Framework — is cited. Compliance is asserted and partly evidenced, but not documented to the level a European procurement team usually asks for.
Who owns the data?
Under section 7 of the terms, effective 27 March 2026, the customer retains all rights to the content it uploads or provides through the service, which covers knowledge bases, contact lists, agent configurations, call recordings and transcripts. Uploading grants Stellar only a limited license to use, process and store that content for the sole purpose of providing the service. The platform itself, its software, technology and content remain Stellar's property. The privacy policy states that personal information is not sold. Customer data may nonetheless pass to a successor entity in the event of a merger, acquisition or sale of assets.
Reuse rights
The customer can reuse, export or delete its own data without asking Stellar for permission: the privacy policy documents export and deletion rights, and recordings and transcripts can be purged automatically on a schedule the account sets. On Stellar's side, section 2 of the privacy policy lists seven purposes: providing the service, managing accounts, AI and voice processing, improvements and analytics, communications, security and fraud prevention, and legal compliance. AI processing covers speech-to-text, text-to-speech and large language models. Data is collected from three sources: what the customer provides, what is captured automatically (recordings, transcripts, call metadata, usage, device data and cookies), and what flows in from connected third-party tools. Eight subprocessors are named: Vapi for voice infrastructure, OpenAI for language models and embeddings, Supabase for database and authentication, Stripe and Polar.sh for payments, Resend for email, Vercel for hosting and Railway for API hosting. Neither the terms nor the privacy policy takes any position on whether customer data is used to train models: the documents neither claim it nor rule it out, which is why the position is recorded here as unclear. The self-learning feature described on the site adjusts the account's own agent after each call, applying changes above a 0.85 confidence threshold and queuing the rest for human review; it is not presented as cross-customer training.
Data retention & training
Hosting summary
Stellar publishes no hosting jurisdiction. Neither the privacy policy nor any other page names a country or region where customer data is stored, and no data residency option is offered. What is named is the infrastructure supply chain: Vercel for web hosting, Railway for API hosting and Supabase for the database and authentication, alongside Vapi for voice, OpenAI for language models and embeddings, Stripe and Polar.sh for payments and Resend for email — eight subprocessors in all, listed by name in the privacy policy dated 27 March 2026. The site's own IP address resolves onto an Amazon network (AS16509) on an anycast route, but that is a network observation, not a statement by the publisher. On security, the site claims TLS 1.2 or above in transit, AES-256-GCM at rest for sensitive data and OAuth tokens, and tenant isolation through row-level security, with every query filtered by account so that cross-tenant access is, in its words, architecturally impossible. SOC 2 is described as readiness verified, a prepared audit rather than an obtained certification, and no ISO 27001 is claimed. Buyers with a data residency requirement will have to ask directly.
Where Stellar works
Country-level availability.
Available in
Things to keep in mind
Risks and trade-offs to weigh before adopting Stellar.
- The publisher cannot be identified. There is no company form, no postal address, no legal notice and no named officer anywhere on the site. If a billing dispute or a data incident arises, your counterparty on record is the word “Stellar” and the law of Delaware, nothing more.
- Three domains coexist in the legal documents. The product runs on saystellar.com, the privacy policy describes the site it covers as stellar.ai, legal and billing contacts are on stellar.ai, and press and partner contacts are on usestellar.ai — a domain that does not resolve in DNS, so those addresses are most likely undeliverable.
- The domain was registered on 25 March 2026 and the terms and privacy policy took effect on 27 March 2026. There is no Wayback Machine capture and no verifiable history, which is a real operational risk when your entire inbound phone line is routed through the vendor.
- The legal exposure sits with you. The site provides compliance tooling but states that you are the seller of record and remain responsible for regulatory adherence in your jurisdiction. Liability is capped at the greater of twelve months of fees or USD 100, individual arbitration is mandatory, class actions are waived, and subscriptions are generally non-refundable.
- Security and privacy claims stop short of proof. SOC 2 is readiness verified rather than certified, no hosting country or region is disclosed, no data processing agreement exists, no EU Article 27 representative is designated, and there is no documented way to keep your data out of model training — the privacy policy takes no position on the question at all.
- The voice stack runs on Vapi, a third party Stellar names on its own comparison page, so part of the processing chain sits with a supplier whose terms are outside this listing. Separately, the performance figures displayed on the site — conversion rising from 14% to 34%, up to 38% fewer no-shows, 56.4x ROI — are illustrations with no published methodology and should not be read as measured results.
- Handing the whole phone line to an agent has a human cost. Every call is recorded, transcribed and scored, so staff and callers need to be told; and a team that stops answering the phone gradually loses its feel for what customers actually ask. Keep listening to a sample of calls yourself, and test the escalation path to a human before you stop watching.
Setup & Integrations
Technical difficulty
Low. Stellar is no-code end to end and no developer is required: pick a template, choose a voice and personality, upload the knowledge base and connect a calendar. The site advertises an agent live in about ten minutes and most teams operational within 30, with one-click integrations said to take under two minutes each. There is no data migration to plan when coming from another tool, and compliance settings are active by default with nothing to configure first. Technical teams have optional depth through the REST API, API keys and outbound webhooks, all available from the entry-level Growth plan.
Deployment
Integrations
Supported languages
Behind Stellar
Social
Resources
All the official URLs gathered for verification and reference.
Alternatives
Tools that compete with or complement Stellar.
Frequently asked questions
What is Stellar?
Do I need technical skills, and how long does setup take?
How much does Stellar cost?
Is there a free trial, and what happens when it ends?
Which tools does Stellar integrate with?
Can I keep my existing phone number?
What happens when the agent does not know the answer?
Which languages do the voice agents support?
Is Stellar compliant with TCPA and GDPR?
Who publishes Stellar?
Should you pick Stellar?
Stellar is a dense, well-priced product wrapped around an opaque publisher, and both halves of that sentence deserve equal weight.
The product side is convincing. Pricing is public down to the per-minute overage rate on every tier, which is rare in this market. The 16 industry packs make the agent useful on day one without prompt engineering, setup genuinely looks like a matter of minutes rather than weeks, and US telephone compliance — FCC one-to-one consent, calling windows, AI and recording disclosure, real-time DNC — is switched on by default instead of sold as an upgrade. The 14-day trial of the full Growth plan runs without a card, and nothing is deleted when it lapses.
The publisher side is where caution belongs. Stellar publishes no company form, no registered address, no named officer and no founding date; the contracting party in the terms is simply “Stellar”, governed by Delaware law. Its legal and privacy contacts sit on stellar.ai and its press contacts on usestellar.ai, while the product runs on saystellar.com — and the privacy policy itself refers to the site as stellar.ai. The domain was registered on 25 March 2026 and the legal documents took effect two days later, so there is no track record to check. SOC 2 is described as readiness verified, a prepared audit rather than a certification, and no data processing agreement is published.
Add the practical limits — English only, numbers in four countries, no permanent free tier — and the picture is clear enough. At USD 149 per month plus overage, Stellar is a real commitment for a small business: a sound one if the phone is your main channel and you are comfortable trusting a vendor you cannot name.
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