Synthflow Pricing 2026: Plans, Costs & Alternatives

Synthflow uses a usage-based pricing model starting at $0.10 per minute for voice calls, with a free tier offering 100 minutes per month. This article breaks down Synthflow's published pricing structure, what's included in the per-minute rate, and how to estimate your monthly bill.

Major takeaways

How much does Synthflow cost? Synthflow charges per minute of call time, starting at $0.10/minute on the free tier and scaling down to $0.05/minute on enterprise plans, plus optional platform fees for advanced features.

What's included in the per-minute rate? The per-minute rate covers telephony, speech-to-text, text-to-speech, and LLM inference costs, according to Synthflow's pricing page, though specific provider details are not disclosed.

What else should you budget for? Phone number rentals ($1–5/month per number), premium voice models, CRM integrations, and engineering time to build and maintain conversation flows add to the base per-minute cost.

Quick answer: Synthflow pricing at a glance

What Synthflow is

Synthflow is a no-code AI voice agent builder designed for operations teams, contact centers, sales teams, and developers who need to deploy conversational AI without writing code.

Users build voice agents through a visual flow builder, connecting nodes for speech recognition, LLM reasoning, API calls, and responses. Synthflow agents handle both inbound calls (customer support, appointment scheduling, lead qualification) and outbound calls (follow-ups, reminders, surveys). The platform integrates with CRMs, calendars, and helpdesk systems.

Synthflow is positioned as a developer-friendly alternative to fully managed voice-AI services, giving teams control over conversation logic while abstracting telephony infrastructure.

How Synthflow pricing works

The pricing model

Synthflow uses a hybrid pricing model combining per-minute usage charges with optional monthly platform fees. The per-minute rate decreases as you move up tiers or commit to higher volumes.

Free and Starter tiers operate month-to-month. Pro and Enterprise plans offer annual contracts with volume discounts.

Billing is based on connected call time, meaning minutes where the AI agent is actively speaking or listening, not total call duration including hold time or transfers to humans, according to Synthflow's documentation.

What the per-minute rate covers

Synthflow's published per-minute rates bundle telephony (inbound and outbound calling infrastructure), speech-to-text transcription, LLM inference for conversation logic, and text-to-speech synthesis. The pricing page does not specify which STT, LLM, or TTS providers are included at each tier.

Premium voice models (higher-quality TTS) and premium LLM models (GPT-4 vs GPT-3.5, for example) may incur additional per-minute charges, though the pricing page does not list specific upcharges. Phone number rental and SMS are billed separately.

Limits and add-ons

The Free tier caps usage at 100 minutes per month. Starter and Pro tiers have no published minute caps but charge overage at the tier rate.

Concurrency limits (the number of simultaneous calls an account can handle) are not specified on the pricing page. Buyers should confirm limits with Synthflow sales.

Phone numbers cost $1–5 per month depending on country and type (local, toll-free, international). Premium voices and premium LLM models are available as add-ons; pricing is not publicly listed. CRM and calendar integrations are included in all tiers. Priority support and dedicated onboarding are Enterprise-only features.

Plan breakdown

Free tier

Designed for developers and small teams testing Synthflow's capabilities. The 100-minute cap supports roughly 50 inbound calls at 2 minutes each or 100 outbound reminder calls at 1 minute each. No credit card required.

Flows are limited to 10 nodes; advanced integrations (Salesforce, HubSpot) are not available. Suitable for proof-of-concept projects but not production workloads.

Starter tier

Removes the minute cap and unlocks custom phone numbers. The $29 platform fee is fixed; all usage above that is billed at $0.08/minute. A team handling 1,000 minutes per month pays $29 + (1,000 × $0.08) = $109/month.

Includes standard voices and GPT-3.5-class LLM models. Works for appointment-setting teams, small contact centers, or sales teams running low-volume outbound campaigns.

Pro tier

Drops the per-minute rate to $0.06 and adds an analytics dashboard, A/B testing for conversation flows, and priority email support. The $99 platform fee makes sense for teams using more than 1,167 minutes per month (breakeven vs Starter: $99 + 1,167 × $0.06 ≈ $29 + 1,167 × $0.08).

Suitable for mid-market operations teams, customer success teams handling inbound inquiries, or sales teams running multi-channel outreach with voice as one channel.

Enterprise tier

Custom pricing with volume commitments. The per-minute rate drops to $0.05 or lower depending on committed volume.

Includes dedicated customer success, SLA guarantees, premium voice models, and access to GPT-4 or other advanced LLMs. Buyers typically commit to 10,000+ minutes per month on an annual contract. Works for contact centers, insurance agencies, healthcare providers, or any team where voice is a primary customer channel and compliance (HIPAA, PCI-DSS) is required.

Estimate your monthly cost

Use this formula to estimate your Synthflow bill:

Monthly cost ≈ (calls per month × average minutes per call × per-minute rate) + platform fee + phone number fees + add-ons

Calls per month: For inbound, use your current call volume. For outbound, multiply your contact list by your expected connect rate (typically 20–40% for B2B cold calls, 60–80% for warm follow-ups).

Average minutes per call: Inbound support calls average 3–5 minutes; appointment-setting calls average 2–3 minutes; outbound qualification calls average 1–2 minutes. Check your current call logs or run a pilot to get real data.

Per-minute rate: Use the published rate for your tier ($0.10, $0.08, $0.06, or $0.05). If you're using premium voices or models, add the upcharge (confirm with Synthflow sales).

Platform fee: $0 (Free), $29 (Starter), $99 (Pro), or custom (Enterprise).

Phone number fees: $1–5 per number per month, depending on country and type.

Add-ons: Premium voices, premium LLM models, extra integrations (pricing not publicly listed).

Illustrative scenarios

The table below shows three volume scenarios using published rates. Every input is an illustrative assumption; replace these with your own call data.

Assumptions: Connect rates of 100% (inbound) or 30% (outbound). No premium models. No failed-call charges. Replace these assumptions with your own data to get a realistic estimate.

Hidden and adjacent costs

Telephony and phone numbers

Phone number rental is billed separately from per-minute usage. Local numbers cost $1–2/month; toll-free numbers cost $2–5/month; international numbers vary by country.

If you need multiple numbers (different regions, different campaigns, A/B testing), budget $5–20/month for a small operation or $50–200/month for a multi-region contact center. Outbound calling to international destinations may incur higher per-minute rates; confirm with Synthflow if your use case involves cross-border calls.

LLM and voice-model upgrades

Synthflow's published per-minute rates include standard LLM models (reportedly GPT-3.5-class) and standard TTS voices. Upgrading to GPT-4 or premium voices (higher naturalness, lower latency) adds a per-minute upcharge.

The pricing page does not list these upcharges; buyers report estimates of $0.01–0.03/minute for premium models based on third-party sources. If your use case requires high-quality voices (customer-facing sales calls, healthcare) or advanced reasoning (complex multi-step workflows), budget an extra 15–30% on top of the base per-minute rate.

Engineering time to build and maintain flows

Synthflow is no-code, but building production-ready conversation flows still requires time.

Initial setup (flow design, integration configuration, testing) takes 10–40 hours depending on complexity. Ongoing maintenance (updating scripts, fixing edge cases, adding new intents) averages 5–10 hours per month for a simple flow or 20–40 hours per month for a complex multi-branch flow. If you're using internal resources, budget the opportunity cost. If you're hiring a contractor or agency, expect $50–150/hour for voice-AI specialists.

Integrations (CRM, calendar, helpdesk)

CRM and calendar integrations are included in all tiers, but connecting to enterprise systems (Salesforce, HubSpot, ServiceNow) may require custom API work.

Synthflow provides pre-built connectors for common platforms; less common systems require webhook or Zapier integrations, which add setup time. Budget 5–15 hours for initial integration work and 2–5 hours per month for maintenance (handling API changes, adding new fields).

QA and call review

Voice agents require ongoing quality assurance. Listen to a sample of calls weekly to catch edge cases, misunderstandings, or tone issues.

For a small operation (500 calls/month), budget 2–4 hours per week for QA. For a high-volume operation (10,000+ calls/month), budget a dedicated QA role (40 hours/week) or use Synthflow's analytics dashboard to flag low-confidence interactions for manual review. Call recording storage is included; transcription and sentiment analysis may incur additional costs (not specified on the pricing page).

Compliance work (consent, recording, data retention)

If you're operating in regulated industries (healthcare, finance, insurance) or jurisdictions with strict call-recording laws (California two-party consent, GDPR), budget time for compliance setup.

Synthflow supports call-recording disclosures and consent capture, but you need to configure these in your flows. Legal review of scripts and disclosures takes 5–10 hours initially.

Data retention policies (how long call recordings are stored, where they're stored, who has access) must be configured; Synthflow's Enterprise plan includes data residency options, but the pricing page does not specify whether HIPAA-compliant infrastructure is included or requires an add-on.

Is Synthflow worth the price?

Synthflow's pricing is competitive for teams that need control over conversation logic and can invest engineering time in flow design. The per-minute rates ($0.05–0.10) are in line with other no-code voice platforms like Vapi and Bland AI. The free tier is useful for testing; the Starter and Pro tiers suit small-to-mid-market teams with predictable call volumes.

Synthflow delivers good value for operations teams that already have technical resources (developers, RevOps, or IT) and want to customize conversation flows without vendor lock-in. The visual flow builder gives more control than fully managed services, and the bundled telephony/STT/TTS/LLM stack simplifies billing compared to platforms that charge separately for each component.

Synthflow is less suitable for non-technical teams that need a managed service with pre-built templates and dedicated onboarding. The platform requires upfront investment in flow design and testing. Teams without in-house technical resources should budget for contractor or agency support, which can add $2,000–10,000 to the first month's cost.

Public review volume for Synthflow is limited; the recurring themes below are drawn from the available G2 / Trustpilot / TrustRadius coverage. Buyers report that Synthflow's analytics dashboard is less detailed than competitors like Retell AI, making it harder to diagnose call failures or optimize flows. Some users note that the platform's documentation assumes familiarity with API concepts, which can slow onboarding for non-developers.

Synthflow alternatives to price against

Vapi: API-first platform with no platform fee and a lower per-minute rate ($0.05). Works for developers who want to build custom integrations and don't need a visual flow builder. Vapi requires more technical setup than Synthflow but offers more flexibility. Compare Vapi if you have engineering resources and want to minimize per-minute costs. See the Vapi vs Retell AI vs Bland AI vs Synthflow comparison for a detailed breakdown.

Retell AI: Charges $0.08/min plus a $50/month platform fee. Includes a more detailed analytics dashboard than Synthflow, with call transcripts, sentiment analysis, and intent-detection reports. Works for teams that need to monitor call quality closely (customer support, healthcare, compliance-heavy industries). Compare Retell AI if analytics and QA are priorities. See the Retell AI pricing guide for plan details.

Bland AI: Focused on outbound calling with a $0.09/min rate and no platform fee. Includes voicemail detection and retry logic optimized for sales campaigns. Works for outbound-focused teams that don't need inbound capabilities. Compare Bland AI if you're running high-volume outbound campaigns and want to avoid platform fees. See the Bland AI vs Retell AI comparison for feature trade-offs.

11x (Julian): AI phone agent for inbound sales calls, sold as part of the 11x platform alongside Alice (AI SDR for outbound email and LinkedIn). Julian handles inbound speed-to-lead, qualification, and routing. Pricing is custom and not published; buyers typically commit to a platform license that includes both Alice and Julian. Works for revenue teams that want a unified outbound + inbound AI system. Compare 11x if you're already evaluating AI SDRs and want voice as part of a multi-channel platform.

Vocode: Open-source voice-agent framework that you can self-host (free) or use as a managed service ($0.10/min). Works for developers who want full code-level control and can manage infrastructure. Self-hosting requires DevOps resources but eliminates per-minute costs beyond your own cloud and API bills. Compare Vocode if you have engineering capacity and want to avoid vendor lock-in.

How to negotiate Synthflow pricing

Commit to volume for a lower per-minute rate

Synthflow's Enterprise tier offers custom pricing based on committed monthly minutes. If you can forecast 10,000+ minutes per month, ask for a volume discount. Buyers report per-minute rates as low as $0.04 for commitments above 50,000 minutes per month, based on third-party sources. Lock in a rate for 12 months to avoid mid-contract price increases.

Ask what's included in the per-minute rate

Confirm whether the quoted rate includes premium voices, premium LLM models, and international calling. Some vendors quote a base rate that only covers standard models and domestic calls, then add upcharges for upgrades. Get a written breakdown of what's bundled and what costs extra.

Cap overage charges

If you're on a tiered plan (Starter, Pro), ask for an overage cap. Some vendors will agree to a maximum monthly bill (e.g., $500/month) to protect you from unexpected spikes. This is especially useful if you're running a pilot and can't predict call volume accurately.

Negotiate concurrency limits

Concurrency (the number of simultaneous calls your account can handle) is often a hidden constraint. Confirm the limit for your tier and ask for an increase if you expect high call volume during peak hours. Some vendors charge extra for higher concurrency; others include it in the Enterprise plan.

Pilot before committing to an annual contract

Start with a month-to-month plan (Free, Starter, or Pro) and run a 30–60 day pilot before signing an annual Enterprise contract. Use the pilot to validate call quality, measure connect rates, and identify edge cases. Lock in annual pricing only after you've confirmed the platform meets your needs.

Confirm data-retention and compliance terms

If you're in a regulated industry, confirm that Synthflow's infrastructure meets your compliance requirements (HIPAA, PCI-DSS, GDPR). Ask whether data residency (storing call recordings in specific regions) is included or requires an add-on. Get written confirmation of data-retention policies and who has access to call recordings.

Verdict

Synthflow's pricing suits small-to-mid-market teams with technical resources who need control over conversation logic and can invest time in flow design. The free tier is useful for testing; the Starter and Pro tiers work for teams handling 1,000–10,000 minutes per month. The per-minute rates are competitive, and the bundled telephony/STT/TTS/LLM stack simplifies billing.

Synthflow is less suitable for non-technical teams that need pre-built templates and managed onboarding, or for high-volume operations that require detailed analytics and call-quality monitoring. Teams without in-house developers should budget for contractor support. Teams that need advanced analytics should compare Retell AI; teams focused on outbound should compare Bland AI or Vapi.

For revenue teams evaluating AI voice agents as part of a multi-channel sales platform, 11x's Julian (inbound AI phone agent) is worth comparing if you're also evaluating AI SDRs for outbound. Synthflow is the stronger fit for operations teams that need a standalone voice platform with full control over conversation flows.

Frequently asked questions

How much does Synthflow cost per minute?

Synthflow charges $0.10 per minute on the Free tier, $0.08/min on Starter, $0.06/min on Pro, and $0.05/min on Enterprise, as listed on Synthflow's pricing page. Premium voice models and premium LLM models may incur additional per-minute charges; pricing for these add-ons is not publicly listed.

Does Synthflow have a free trial?

Synthflow offers a free tier with 100 minutes per month, no credit card required. This is a permanent free tier, not a time-limited trial. The 100-minute cap is suitable for testing and low-volume pilots but not production workloads.

Is telephony included in Synthflow's pricing?

Yes. Synthflow's per-minute rates include telephony (inbound and outbound calling infrastructure), speech-to-text, LLM inference, and text-to-speech, according to the pricing page. Phone number rental ($1–5/month per number) is billed separately.

Does Synthflow charge for failed or unanswered calls?

The pricing page does not specify whether failed or unanswered calls are billed. Buyers should confirm with Synthflow whether charges apply to calls that go to voicemail, are declined, or fail to connect. Some voice platforms charge for any call attempt; others only charge for connected calls.

Is there a minimum contract?

Free, Starter, and Pro tiers operate month-to-month with no minimum contract. Enterprise plans typically require an annual contract with a committed monthly minute volume. Buyers report minimum commitments of 10,000 minutes per month on Enterprise plans, based on third-party sources.

How does Synthflow pricing compare to hiring a human receptionist or SDR?

A full-time receptionist or SDR costs $40,000–60,000 per year in salary plus benefits, equipment, and training. Synthflow's cost depends on call volume. A team handling 5,000 minutes per month on the Pro tier pays roughly $459/month ($99 platform fee + 5,000 × $0.06 + phone numbers), or $5,508 per year. The AI agent handles calls 24/7 and scales instantly, but requires upfront engineering time to build flows and ongoing QA. Use the SDR cost calculator to compare total cost of ownership for your specific volume.

What's the cheapest alternative to Synthflow?

Vapi offers a lower per-minute rate ($0.05) with no platform fee, making it cheaper for high-volume use cases. Vocode's open-source version is free if you self-host, though you'll pay for cloud infrastructure and API costs (STT, LLM, TTS). Bland AI charges $0.09/min with no platform fee, which is cheaper than Synthflow's Starter tier for volumes above 1,450 minutes per month.

How does Synthflow compare to 11x's Julian?

Julian is an AI phone agent for inbound sales calls, sold as part of the 11x platform alongside Alice (AI SDR for outbound email and LinkedIn). Julian handles inbound speed-to-lead, qualification, and routing; pricing is custom and not publicly listed. Synthflow is a standalone no-code voice platform with published per-minute pricing, suitable for operations teams that need control over conversation flows. 11x is the stronger fit for revenue teams that want a unified outbound + inbound AI system; Synthflow suits operations teams that need a flexible voice platform without bundling outbound SDR capabilities.

Last updated: October 2026.