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Synthflow alternatives: 4 apps ranked by verified data

Facts checked Nov 8, 2026AppBreakup editorialHow we rankAll voice AI agent platforms

Top picks

  • Vapi logo

    Best overall

    Vapi

    Starting price: $29 per month (Core package)

  • ElevenLabs logo

    Best free option

    ElevenLabs

    Starting price: $6 per month (Starter)

Common reasons people leave Synthflow: no free plan, trial or pay-as-you-go option, and sold only as an annual enterprise contract. We ranked 4 alternatives by how directly each one replaces Synthflow, then by reviews, real visits and how recently each app's facts were checked against its own website. Vapi currently ranks first.

Quick comparison

#AppPricingVerified priceOpen sourcePlatformsVerified factsScore
1Vapi logoVapiFree plan + paid$29 per month (Core package)NoWeb7 of 768.8
2ElevenLabs logoElevenLabsFree plan + paid$6 per month (Starter)NoWeb, iOS, Android6 of 654.4
3Voiceflow logoVoiceflowPaid—NoWeb4 of 452.6
4Yellow.ai logoYellow.aiFree plan + paid$0.99 per resolution after free sessionsNoWeb5 of 551.2
  1. Vapi logo

    1. VapiTop pick

    Best for: Developer teams that want to mix their own speech, LLM and voice providers in phone agents

    Free plan + paidWeb

    68.8

    score / 100

    Why switch from Synthflow

    Developer-first voice agent API with pay-as-you-go usage pricing instead of an annual contract.

    Pros

    • Choose your own transcriber, model and voice providers
    • Model costs passed through without markup
    • Built-in call testing, simulation and monitoring
    • Usage-only start with free credits and no minimum minutes

    Cons

    • Total per-minute cost depends on several providers and is hard to predict
    • HIPAA support is a separate monthly add-on
    • Low-tier plans include only a few concurrent calls
    Visit Vapi Details and reviews
    How this score is calculated
    Editorial fit ×0.3100
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.15100
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is Vapi a good Synthflow alternative?

    Verified facts

    7 of 7 verified
    Free credits
    $5 to start
    Checked Nov 8, 2026vapi.ai(opens source in a new tab)
    Hosting fee
    $0.05 per minute, models passed through at cost
    Checked Nov 8, 2026vapi.ai(opens source in a new tab)
    Core package
    $29 per month
    Checked Nov 8, 2026vapi.ai(opens source in a new tab)
    Model pricing
    Passed through at cost
    Checked Nov 8, 2026vapi.ai(opens source in a new tab)
    Compliance
    SOC 2, HIPAA, PCI
    Checked Nov 8, 2026vapi.ai(opens source in a new tab)
    Starting price
    $29 per month (Core package)
    Checked Nov 8, 2026vapi.ai(opens source in a new tab)
    Pro plan
    $999 per month minimum
    Checked Nov 8, 2026vapi.ai(opens source in a new tab)
  2. ElevenLabs logo

    2. ElevenLabs

    Best for: Creators and developers who need realistic AI voiceovers, voice clones or dubbing

    Free plan + paidWeb, iOS, Android

    54.4

    score / 100

    Why switch from Synthflow

    ElevenLabs Agents pairs its well-known voices with self-serve plans for phone and web voice agents.

    Pros

    • Very natural, expressive voices across 90+ languages
    • Large voice library plus instant and professional voice cloning
    • Dubbing, music and sound effects in the same subscription
    • Well-documented API used by many apps

    Cons

    • Free plan has no commercial license
    • Credits are used fast on long audiobooks or dubbing
    • Professional voice cloning needs the Creator plan or higher
    Visit ElevenLabs Details and reviews
    How this score is calculated
    Editorial fit ×0.352
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.15100
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is ElevenLabs a good Synthflow alternative?

    Verified facts

    6 of 6 verified
    Free plan
    Yes, 10,000 credits/month
    Checked Nov 8, 2026elevenlabs.io(opens source in a new tab)
    Starting price
    $6 per month (Starter)
    Checked Nov 8, 2026elevenlabs.io(opens source in a new tab)
    Languages
    90+
    Checked Nov 8, 2026elevenlabs.io(opens source in a new tab)
    Voice library
    17,500+ voices
    Checked Nov 8, 2026elevenlabs.io(opens source in a new tab)
    Creator plan
    $22 per month
    Checked Nov 8, 2026elevenlabs.io(opens source in a new tab)
    Pro plan
    $99 per month
    Checked Nov 8, 2026elevenlabs.io(opens source in a new tab)
  3. Voiceflow logo

    3. Voiceflow

    Best for: CX and product teams or agencies building production AI support agents for chat and phone

    PaidWeb

    52.6

    score / 100

    Why switch from Synthflow

    Visual agent designer that covers both chat and phone voice, with self-serve plans.

    Pros

    • Combines LLM playbooks with deterministic workflows in one builder
    • Deploys to web chat, WhatsApp, SMS and voice
    • Choice of model provider or bring your own model
    • Built-in conversation testing and staging environments

    Cons

    • No free plan for ongoing use, only a trial
    • Business pricing isn't published and requires talking to sales
    • More setup than simple 'train on your docs' chatbot tools
    Visit Voiceflow Details and reviews
    How this score is calculated
    Editorial fit ×0.346
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.15100
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is Voiceflow a good Synthflow alternative?

    Verified facts

    4 of 4 verified
    Free trial
    Yes, no card needed
    Checked Nov 8, 2026voiceflow.com(opens source in a new tab)
    Billing
    Usage-based
    Checked Nov 2, 2026voiceflow.com(opens source in a new tab)
    Model choice
    Major LLM providers or your own model
    Checked Nov 8, 2026voiceflow.com(opens source in a new tab)
    Channels
    Web, app, WhatsApp, SMS, voice
    Checked Nov 2, 2026voiceflow.com(opens source in a new tab)
  4. Yellow.ai logo

    4. Yellow.ai

    Best for: Large enterprises automating support across voice, chat and email in many languages

    Free plan + paidWeb

    51.2

    score / 100

    Why switch from Synthflow

    Enterprise customer-service automation spanning voice and chat channels in one platform.

    Pros

    • Covers voice, chat, email and SMS in one platform
    • Large catalogue of ready-made enterprise integrations
    • Wide language support for voice agents
    • Free tier to try the builder before talking to sales

    Cons

    • Enterprise pricing is quote-only
    • Free plan is limited to one agent and low volume
    • More complex to adopt than self-serve chatbot builders
    Visit Yellow.ai Details and reviews
    How this score is calculated
    Editorial fit ×0.341
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.15100
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is Yellow.ai a good Synthflow alternative?

    Verified facts

    5 of 5 verified
    Free plan
    Yes, 500 sessions/month included
    Checked Nov 8, 2026yellow.ai(opens source in a new tab)
    Integrations
    150+
    Checked Nov 8, 2026yellow.ai(opens source in a new tab)
    Models
    15+ LLMs
    Checked Nov 8, 2026yellow.ai(opens source in a new tab)
    Voice languages
    500+
    Checked Nov 8, 2026yellow.ai(opens source in a new tab)
    Usage price
    $0.99 per resolution after free sessions
    Checked Nov 8, 2026yellow.ai(opens source in a new tab)

The best Synthflow alternative for…

The highest-ranked app in this list for each need.

Vapi logo

Best Synthflow alternative for most people

Vapi

Developer-first voice agent API with pay-as-you-go usage pricing instead of an annual contract.

ElevenLabs logo

Best Synthflow alternative for a free plan you can upgrade

ElevenLabs

ElevenLabs Agents pairs its well-known voices with self-serve plans for phone and web voice agents.

ElevenLabs logo

Best Synthflow alternative for iPhone and Android

ElevenLabs

ElevenLabs Agents pairs its well-known voices with self-serve plans for phone and web voice agents.

Voiceflow logo

Best Synthflow alternative for working in the browser

Voiceflow

Visual agent designer that covers both chat and phone voice, with self-serve plans.

Synthflow alternatives: common questions

What is the best alternative to Synthflow?

Vapi ranks first right now. Developer-first voice agent API with pay-as-you-go usage pricing instead of an annual contract. ElevenLabs and Voiceflow follow it in our ranking.

Synthflow vs Vapi: what's the difference?

Synthflow is a paid product; Vapi is free with paid plans. Both run on Web.

Is Synthflow free?

Synthflow is a paid product. Pricing: Annual enterprise agreement; Free plan: No. Checked on Synthflow's own site, November 2026.

How much do Synthflow alternatives cost?

Verified prices for the top-ranked Synthflow alternatives: Vapi, $29 per month (Core package); ElevenLabs, $6 per month (Starter); Yellow.ai, $0.99 per resolution after free sessions. Each price was checked on the app's own site; see each card below for the date and source.

Is there a free alternative to Synthflow?

Yes. Vapi (free plan + paid), ElevenLabs (free plan + paid) and Yellow.ai (free plan + paid) have a free option. Check each app's verified facts for current plan limits.

Is there an open-source alternative to Synthflow?

None of the 4 alternatives in this list is open source.

Why do people switch from Synthflow?

The complaints we hear most: no free plan, trial or pay-as-you-go option; sold only as an annual enterprise contract; not suited to developers wanting to experiment cheaply.

How is this list ranked?

Every app is scored with the same published formula: how directly it replaces Synthflow, reviews (weighted by verification), visits from AppBreakup, how recently its facts were checked against its own website, and reader votes.