Best AI search API for agents
Research agents need search APIs that return citations, not just links. These are the AI search APIs we recommend for agent stacks in 2026.
Quick answer
- Best overall:
- Perplexity Sonar API
- Best for citations:
- You.com Research API
- Best for scale:
- Exa
- Best budget option:
- Tavily
What to avoid: Choosing a raw web-search API without citation formatting — you'll rebuild that layer yourself.
Last verified: July 2026
Comparison matrix
| Tool | Best for | API | Free | Pricing | Strength | Limitation | Score | Verified | Try |
|---|---|---|---|---|---|---|---|---|---|
| Perplexity Sonar API | AI-native search + citations | From $5 credit | Answers with sources | Rate-limited on lower tiers | 9.3 | 2026-07 | |||
| Exa | Neural search at scale | From $10/mo | Semantic web index for agents | Fewer freshness signals | 9.0 | 2026-07 | |||
| You.com Research API | Agent research workflows | Pay-per-request | Deep research + citations | Newer surface | 8.9 | 2026-07 | |||
| Tavily | Budget agent search | 1000 free/mo | Cheapest useful research API | Shallower answers than Perplexity | 8.5 | 2026-07 |
Perplexity Sonar API
Score 9.3AI-native search + citations
- API
- Yes
- Free tier
- No
- Pricing
- From $5 credit
- Strength
- Answers with sources
- Limitation
- Rate-limited on lower tiers
- Verified
- 2026-07
Exa
Score 9.0Neural search at scale
- API
- Yes
- Free tier
- Yes
- Pricing
- From $10/mo
- Strength
- Semantic web index for agents
- Limitation
- Fewer freshness signals
- Verified
- 2026-07
You.com Research API
Score 8.9Agent research workflows
- API
- Yes
- Free tier
- Yes
- Pricing
- Pay-per-request
- Strength
- Deep research + citations
- Limitation
- Newer surface
- Verified
- 2026-07
Tavily
Score 8.5Budget agent search
- API
- Yes
- Free tier
- Yes
- Pricing
- 1000 free/mo
- Strength
- Cheapest useful research API
- Limitation
- Shallower answers than Perplexity
- Verified
- 2026-07
When to use these
Use for research copilots, sales-intel agents, competitive monitors and briefing generators.
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FAQ
Which search API returns citations?
Perplexity Sonar, You.com Research and Tavily all return structured citations agents can attribute.