Best for
Best for teams who need a transcript accurate enough to be relied on in court or in the record, with a human pass available on top of the machine one.
- Freelancers
- Small and mid-sized
- Enterprise
AI Voice & Speech Comparison
Rev vs. Synthflow
At a glance
At a glance
Best for
Best for contact centres and outsourcers that want phone agents built, branded and launched under one contract.
- Enterprise
Cataleo does not name a winner. Both statements come from the vendors themselves.
Full Comparison
| Criterion | Rev | Synthflow |
|---|---|---|
| Starting price | lower value Free tier, then from $25.49 / seat / month The $25.49 Essentials rate is billed annually at $305.90 a year; paid monthly it is $29.99. Pro is $47.99 billed annually or $59.99 monthly. Human services are bought separately by the minute or page and are pooled across seats at account level. The Rev AI developer platform is billed per hour of audio instead, from $0.10 an hour on Reverb Turbo. | From $30,000 / year Enterprise contracts start there and are scoped around call volume, concurrency, telephony setup, integrations, security needs and launch support. No self-serve tier is published. |
| Free trial | Free plan with 45 AI transcription and caption minutes a month, plus free Rev AI credits worth 5 hours of Reverb transcription | Not stated |
| Commercial use | Not stated | Yes, under an enterprise contract |
| Output | Transcripts, captions, subtitles and case documents | Voice and chat agents for inbound and outbound phone calls, including white-labelled agents resold under a partner's brand |
| API | Yes, Rev AI for asynchronous and streaming speech-to-text, plus a human transcription API | Yes, a public Platform API, plus an MCP server for MCP-capable clients |
| Languages | 57+ languages for the Rev AI speech-to-text API; 37+ on the Pro subscription; human captions in English and Spanish and subtitles in 17 languages | Over 30, plus a multilingual mode that switches languages within one call |
| Hosting | Cloud or on-premises for the Rev AI platform | Cloud, with region-based hosting |
| Voice cloning | No, Rev works only on incoming speech and does not synthesise or clone voices | Cloning happens in ElevenLabs, not in Synthflow. The voice selector offers Synthflow's own TTS with twelve built-in voices and the ElevenLabs models from Turbo v2 and Flash v2.5 up to v3; a cloned or provider-specific voice is added through Imported > Import Voice by pasting the provider voice ID, or by connecting your own ElevenLabs API key so that account's custom voices appear in the selector. The vendor warns that a synthesiser model your own ElevenLabs plan lacks can mean lower quality or higher latency on your key |
| Real-time use | Yes, a streaming speech-to-text API for live audio alongside asynchronous transcription of recorded files; human services are turnaround-based rather than real-time | Yes, live inbound and outbound calls, with IVR handling for outbound agents, voicemail and silence handling, in-call SMS and WhatsApp messaging, and WhatsApp Business calling. The vendor states 99.99% uptime on its own telephony infrastructure |
| Speech-to-speech and dubbing | No dubbing or synthesised speech. Translation is text-only, at $0.002 to $0.025 per minute through the API depending on standard or premium, plus human subtitles at $6.49 to $15.99 a minute | Not documented. The voice documentation covers text-to-speech for live agents, with a speaker and a synthesis model chosen per agent, and carries no speech-to-speech conversion and no dubbing |
| Editing and controls | Transcript editor with clipping, multi-file evidence analysis with citations, image analysis, a document editor exporting to Word and PDF, AI templates for chronologies and affidavits, and API-side custom vocabulary, forced alignment with word-level timestamps, topic extraction and sentiment analysis | Flow Designer, a node-based canvas with conversation, message, branch, jump and custom action nodes, or a simpler prompt builder, plus a multi-agent system for several flows behind one agent, voice model and pacing settings, manual testing, automated simulations and custom evaluations that score calls against business goals |
| Consent and trust | SOC 2, HIPAA, GDPR and PCI compliant with data encrypted at rest and in transit, a stated 99.99% uptime, and on-premises deployment for the API; the Unlimited subscription adds HIPAA and CJIS compliance, SSO and a dedicated specialist | SOC 2, HIPAA, PCI DSS, GDPR and ISO 27001, with encryption, audit logs and region-based hosting. Per-agent controls decide whether recordings and transcripts are kept at all, cap retention at 30 days, and redact personal data from transcripts, webhook payloads and logs |
| MCP-ready | No | stated Yes |
| Deployment | more entries Cloud (SaaS), Browser-based, On-premise | Cloud (SaaS), Browser-based |
| Support | Not stated | Email helpdesk |
| Onboarding | Documentation and knowledge base | more entries Documentation and knowledge base, Personal consulting |
| Company size | more entries Freelancers, Small and mid-sized, Enterprise | Enterprise |
| Integrations | Clio | more entries HubSpot, Salesforce, Zapier, Cal.com, GoHighLevel, Twilio, Genesys, Avaya, Five9, Cisco, RingCentral |
Add a tool
Adds a column to the table, from the tools in this category.
Row where the values differ The small markers point at the lower number, the longer list or the stated feature. They describe the data, they are not a verdict.
The short version
Key Differences
- Starting price Rev Free tier, then from $25.49 / seat / month Synthflow From $30,000 / year
- Deployment Rev Cloud (SaaS), Browser-based, On-premise Synthflow Cloud (SaaS), Browser-based
- Company size Rev Freelancers, Small and mid-sized, Enterprise Synthflow Enterprise
- Hosting Rev Cloud or on-premises for the Rev AI platform Synthflow Cloud, with region-based hosting
- Languages Rev 57+ languages for the Rev AI speech-to-text API; 37+ on the Pro subscription; human captions in English and Spanish and subtitles in 17 languages Synthflow Over 30, plus a multilingual mode that switches languages within one call
Every line is one datapoint from the table above, picked automatically. Nothing here is written text.
The trade-offs
Strengths and Limitations
Rev
Strengths
- Human transcription at a stated 99%+ accuracy alongside the machine tier
- Developer API priced per hour of audio, from $0.10 on Reverb Turbo
- Runs on-premises as well as in the cloud on the API side
- Free credits worth 5 hours of transcription, with no card required
Limitations
- Speech-to-text only, no text-to-speech, dubbing or voice cloning
- The subscription is built around legal and investigative work, which is dead weight for other uses
- The free plan covers 45 minutes a month and English only
- Human services are charged on top of the subscription rather than included
Synthflow
Strengths
- No-code Flow Designer with a multi-agent system, so a non-developer can build and change call flows
- Connects to existing telephony and contact centre stacks over SIP, including Genesys, Avaya, Five9, Cisco and RingCentral
- White-labelled deployments for partners reselling voice agents under their own brand
- SOC 2, HIPAA, PCI DSS, GDPR and ISO 27001, with agent-level retention and PII redaction controls
Limitations
- No self-serve or trial tier is published; the only listed plan is an enterprise contract from $30,000 per year
- Pricing is scoped by sales, so the cost of a given call volume is not knowable from the website
- Latency figures differ between the vendor's own pages, so the published number is not a specification to rely on
- A cloned voice has to be created in a separate ElevenLabs account and imported, so it means a second subscription alongside Synthflow
Plans
Pricing
Rev
- Free $0 45 AI transcription and caption minutes a month, English only, up to 5 files analysed at once, document editor and mobile app.
- Essentials $25.49 Per seat per month billed annually at $305.90, or $29.99 billed monthly. Up to 3 seats, 5,000 AI minutes per seat per month in English and Spanish, up to 10 files analysed and 10% off human services.
- Pro $47.99 Per seat per month billed annually at $575.88, or $59.99 billed monthly. Up to 5 seats, 10,000 AI minutes per seat per month across 37+ languages, up to 50 files analysed, image analysis, Clio integration and 15% off human services.
- Unlimited Not stated Custom pricing. Unlimited seats and AI minutes, up to 500 files analysed, HIPAA and CJIS compliance, SSO and a dedicated specialist.
- Rev AI pay-as-you-go $0.10 Per hour of audio on Reverb Turbo; Reverb is $0.20 an hour and foreign-language transcription $0.30 an hour across 56+ languages. Whisper Fusion and Large are $0.005 a minute. Human transcription through the API is $1.99 a minute. Insights are priced separately: language identification and forced alignment $0.003 a minute, topic extraction and sentiment analysis $0.0008 per 10 words, translation $0.002 to $0.025 a minute. Free credits equivalent to 5 hours of Reverb transcription to start.
- Human services From $1.99 Per minute for human transcription and for human captions, with up to 15% off on a subscription. Legal rough drafts are $2.25 a page and legal premium transcripts $2.50 a page. Global subtitles run $6.49 to $15.99 a minute depending on the language, across 17 languages.
Synthflow
- Enterprise $30,000 Per year, the stated starting point. Scoped around call volume, concurrency, telephony setup, integrations and security needs, and covers implementation, onboarding, testing, training, launch support and ongoing optimisation, with SLA and support terms set in the contract.
What users say
Review Scores · opens after launch
Rev
- Ease of use
- Not rated yet
- User interface
- Not rated yet
- Onboarding
- Not rated yet
- Support and service
- Not rated yet
- Value for money
- Not rated yet
- Features
- Not rated yet
No reviews yet. Be the first to review this tool. Every review is checked for fairness before it appears, and the vendor cannot have one removed.
Synthflow
- Ease of use
- Not rated yet
- User interface
- Not rated yet
- Onboarding
- Not rated yet
- Support and service
- Not rated yet
- Value for money
- Not rated yet
- Features
- Not rated yet
No reviews yet. Be the first to review this tool. Every review is checked for fairness before it appears, and the vendor cannot have one removed.
Where this comes from
Where this comes from
Rev https://www.rev.com · checked against the official source on 2026-09-04
Synthflow https://synthflow.ai · checked against the official source on 2026-09-13
This table lists factual criteria taken from information the vendors publish themselves. For how we put it together, see the methodology.