Transparency disclaimer up front: I am the creator of ZapVox. This comparison is biased by definition — but I commit to one rule: about Kaption AI, I only state what is public on their official page and on the Chrome Web Store. No invented limitations.
If you're choosing an extension to transcribe WhatsApp Web voice messages, these are probably the two options on your list. Let's get to it.
The 30-second summary
- Kaption AI leads the category in installs: its official page cites 40,000+ users and a high rating (4.8★) as of July 2026. If you want the most popular option, that's the one. It has also broadened beyond transcription into translation, summaries, reminders, message scheduling and privacy features (screen lock, blur).
- ZapVox competes on price (R$29.90 /month billed in Brazilian reais), reach (99+ languages), features beyond raw transcription (custom glossary, audio search, daily digest, message scheduling with variables) and locality: built in Brazil, Portuguese support, built under Brazil’s LGPD from day one.
Comparison table
| Criteria | ZapVox | Kaption AI |
|---|---|---|
| WhatsApp Web audio transcription | ✅ Yes | ✅ Yes (category leader) |
| Users (official page / CWS) | Smaller base, growing | 40,000+ (per their site, Jul 2026) |
| Pro pricing | R$29.90/month or R$199.90 /year, in BRL | Billed in USD (see official page) |
| Free plan without credit card | ✅ 10 transcriptions/day, no card | See official page |
| Transcription languages | ✅ 99+ languages (Whisper) | Multilingual support (see official page) |
| Translation & summaries | ✅ Yes (Pro) | ✅ Advertised (live translation, smart summaries) |
| Message scheduling | ✅ Yes (Pro; 3/day on Free), recurrence + variables | ✅ Advertised on official page (Jul 2026) |
| Reminders | ✅ Local reminders, free on any plan | ✅ Advertised (chat reminders) |
| Custom glossary (technical terms, proper names) | ✅ Yes (Pro) | Not advertised on the official page |
| Search across transcribed audios (last 90 days) | ✅ Yes | Full-text search advertised on official page |
| Daily audio digest | ✅ Yes | Not advertised on the official page |
| Bring your own API key (BYOK) | ✅ Groq (free) or OpenAI | Not advertised on the official page |
| LGPD + Portuguese support | ✅ Brazilian company, PT-BR support | International product |
Sources: Chrome Web Store and each product's official page, checked in July 2026. If something changed, email [email protected] and I'll fix it.
Where Kaption AI wins
Honesty requires it: traction and social proof. With 40,000+ users and 4.8 stars (per their official page), Kaption has a validated user base that ZapVox doesn't have yet. For pure audio transcription, it's a mature, well-rated product — I won't pretend otherwise. It has also expanded its feature set (translation, summaries, reminders, scheduling, screen lock, blur mode).
Where ZapVox wins
1. Pricing in BRL, no exchange-rate surprises
R$29.90/month (or R$199.90/year, about R$16.60/month). International competitors bill in USD — for anyone earning in reais, the price floats with the exchange rate and comes with card taxes. Predictability matters.
2. Beyond transcription: search and daily digest
Transcribing is just the start. ZapVox keeps the last 90 days of transcriptions searchable — "which audio had the client's address in it?" becomes a 2-second search. The daily digest compiles everything that arrived as audio during your day, so you don't reopen 14 chats.
3. Custom glossary
Every generic transcriber trips on technical terms: medication names, legal jargon, internal company acronyms. In ZapVox Pro you register your terms in the glossary and transcriptions start respecting them. For doctors, lawyers and sales teams, that moves accuracy from "good" to "usable in records".
4. Message scheduling done responsibly
ZapVox schedules individual messages to a specific contact, with recurrence and variables like {{name}} and {{date}}. It is not a bulk-sending tool — it has built-in anti-block limits (per-hour and per-day caps, time jitter, typing simulation). Prefer not to auto-send? Local reminders are free on any plan. See the full how to schedule WhatsApp messages guide.
5. A real free tier + BYOK
10 transcriptions per day with no credit card. And if you want volume without paying Pro, you can plug in your own free Groq API key (BYOK) — tutorial here on the blog.
6. LGPD and Portuguese support
Brazilian company, privacy policy designed around LGPD (audios discarded after processing, API keys encrypted locally) and support that replies in Portuguese — no machine translation.
Verdict: which one to choose?
- Choose Kaption AI if you want the most-installed option in the category with a large, validated user base.
- Choose ZapVox if you want to pay in BRL, need accuracy on technical terms (glossary), want to find information later (audio search + daily digest), want responsible message scheduling, or value Portuguese support and LGPD compliance.
Best-case scenario: both have free versions. Test both in your real workflow for a week and see which one gives you more time back.
10 transcriptions per day on the Free plan — no credit card required.
Found outdated information about either product? Email [email protected] and we'll fix it fast.