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: 30,000+ users and a high rating (4.8★) on the Chrome Web Store. If you want the most popular option, that's the one.
- 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) and locality: built in Brazil, Portuguese support, LGPD-compliant from day one.
Comparison table
| Criteria | ZapVox | Kaption AI |
|---|---|---|
| WhatsApp Web audio transcription | ✅ Yes | ✅ Yes (category leader) |
| Users (Chrome Web Store) | Smaller base, growing | 30,000+ (per CWS) |
| 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) |
| Custom glossary (technical terms, proper names) | ✅ Yes (Pro) | Not advertised on the official page |
| Search across transcribed audios (last 7 days) | ✅ Yes | Not advertised on the official page |
| Daily audio digest | ✅ Yes | Not advertised on the official page |
| Audio translation and summaries | ✅ Yes (Pro) | See 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 30k+ users and 4.8 stars, 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.
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 7 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. 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.
5. 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 and only need transcription.
- Choose ZapVox if you want to pay in BRL, need accuracy on technical terms (glossary), want to find information later (audio search + daily digest) 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.