Voice AI agents (Vapi, Retell, ElevenLabs) need real-time search grounding to answer factual questions during calls. The search API must return results in under 3 seconds (the natural conversation pause window), provide speakable snippets, and route between platforms based on query type.
Top Pick
Scavio wins for voice agents with sub-2-second response times, AI Overview text that is already speakable, and multi-platform routing (Google for facts, Amazon for prices).
Full Ranking
#1Our Pick
Scavio
Voice agents needing fast multi-platform search grounding
Pros
- Sub-2s response time
- AI Overview text is speakable
- Amazon for product pricing queries
- Structured snippets for TTS
- 500 free/mo for development
Cons
- No voice-specific features
- Snippets may need trimming for TTS
- No conversation context
#2
Perplexity Sonar
Voice agents wanting pre-synthesized conversational answers
Pros
- Pre-synthesized answers
- Conversational tone
- Citation URLs
- Good for QA-style questions
Cons
- Variable latency (2-5s)
- Expensive at volume
- Variable response length
- No multi-platform routing
#3
Tavily
Voice agents wanting AI-summarized web answers
Pros
- AI-optimized results
- 1,000 free/month
- Extract for detailed answers
- LangChain integration
Cons
- Web-only (no Amazon pricing)
- Summarization adds latency
- No voice-specific format
- Higher cost at scale
#4
Serper
High-volume voice agents wanting lowest cost
Pros
- Fastest response time (~1s)
- 2,500 free searches
- Lowest per-query cost
- Simple API
Cons
- Google only
- No AI-summarized answers
- Snippets may not be speakable
- No multi-platform routing
#5
Google Custom Search
Voice agents already in Google Cloud ecosystem
Pros
- Official Google API
- Reliable and well-documented
- Integration with Google Cloud
- Image search support
Cons
- 100/day limit (low for voice)
- No AI Overview data
- Complex setup
- Web-only
Side-by-Side Comparison
| Criteria | Scavio | Runner-up | 3rd Place |
|---|---|---|---|
| Typical Latency | <2s | 2-5s | 1-3s |
| Speakable Output | AI Overview text + snippets | Pre-synthesized answers | AI summary |
| Product Price Data | Yes (Amazon endpoint) | No | No |
| Free Tier | 500/mo | Trial credits | 1,000/mo |
| Multi-Platform Routing | Yes (5 platforms) | No | No |
| Conversation Context | No | Yes (conversational) | No |
Why Scavio Wins
- Sub-2-second response fits within natural conversation pauses. The caller says 'let me check that for you' and the answer arrives before the pause feels awkward.
- AI Overview text is already human-readable and speakable. Voice agents can read it directly without summarization or reformatting.
- Multi-platform routing: product pricing questions go to Amazon, general factual questions to Google, community opinions to Reddit. Better answers per query.
- Structured snippets are predictable length. Voice agents can truncate to 200 characters for a 15-second spoken response, avoiding rambling.
- 500 free credits/mo covers voice agent development and testing. Build the search integration before your first live call.