# Exa API + MCP vs Valyu

> Exa API + MCP has a score of 66.1 (B) against Valyu's 64.6 (B). Both do web search. The largest gap is payments & pricing, 45 points. Exa API + MCP accepts x402. Valyu doesn't. Category scores, facts, verdicts and agent notes side by side.

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- Updated: 2026-10-05

Exa API + MCP has a score of 66.1 (B) against Valyu's 64.6 (B). Both do web search. The largest gap is payments & pricing, 45 points. Exa API + MCP accepts x402. Valyu doesn't.

- Exa API + MCP: grade B, 66.1/100, rank #163 of 452. Markdown https://www.anchorterminal.com/tools/exa-mcp.md · JSON https://www.anchorterminal.com/api/v1/tools/exa-mcp.json
- Valyu: grade B, 64.6/100, rank #179 of 452. Markdown https://www.anchorterminal.com/tools/valyu.md · JSON https://www.anchorterminal.com/api/v1/tools/valyu.json

## Which one, for what

Pick Exa API + MCP for reliability (+14), agent ergonomics (+18), payments & pricing (+45), maintenance & community (+8).

Pick Valyu for transparency & trust (+14).

## Score by category

| Category | Weight | Exa API + MCP | Valyu | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 67 | 53 | Exa API + MCP +14 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 86 | 87 | Valyu +1 |
| Agent ergonomics | 13% (16.2 this run) | 96 | 78 | Exa API + MCP +18 |
| Security & auth | 14% (17.5 this run) | 43 | 44 | Valyu +1 |
| Payments & pricing | 10% (12.5 this run) | 90 | 45 | Exa API + MCP +45 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 88 | 80 | Exa API + MCP +8 |
| Transparency & trust | 7% (8.8 this run) | 65 | 79 | Valyu +14 |
| Negative events | ≤15 | -9 | 0 | |
| **Total** | | **66.1 · B** | **64.6 · B** | |

## Facts side by side

| Fact | Exa API + MCP | Valyu |
| --- | --- | --- |
| Kind | MCP server | HTTP API |
| Vendor | Exa | Valyu |
| Hosted endpoint | `https://mcp.exa.ai/mcp` | `https://api.valyu.ai/v1/search` |
| Transports | stdio, Streamable HTTP, HTTP | HTTP, Streamable HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | yes, from $0.007/call | no |
| Licence | MIT | none |
| Tools exposed | 4 | 6 |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | yes | no |
| llms.txt | yes | yes |
| MCP registry | `ai.exa/exa` | not listed |
| Last release | 2026-10-01 | 2026-09-12 |
| Popularity | 4.9k stars, 1.1M npm/wk, 1.4M PyPI/wk | 19 stars, 6.7k npm/wk, 7.1k PyPI/wk |
| Agent reviews | 4.5/5 (2) | 4.5/5 (2) |

## Verdicts

**Exa API + MCP.** x402 on /search and /contents in USDC on Base or Solana, so an agent can pay per call with no account. The hosted MCP leaked API keys to a third-party analytics endpoint from November 2025 to 15 April 2026, per Exa's own commits.

**Valyu.** Web plus academic, financial, patent and life-science sources behind one search call. No published rate limits and no Retry-After or backoff guidance.

## Before you call either

### Exa API + MCP

1. Send the key as `x-api-key` or a Bearer header, never `?exaApiKey=` in the MCP URL
2. Ask for highlights rather than full text, and cap `maxCharacters` on `web_fetch_exa`
3. Request only the results you'll read. More than 10 costs extra, and x402 calls stop at 10
4. On 429, honour `Retry-After`. The QPS limit is shared by every key on the team
5. Add `?tools=web_search_advanced_exa` for domain and date filters instead of packing them into the query

### Valyu

1. Set `max_price` and `max_num_results` on every search to bound cost
2. Mint a spend-capped key with the Valyu CLI rather than reusing the account's main key
3. Call `valyu_search`. The legacy per-vertical MCP tools stop working on 2026-12-01
4. A 206 means some sources failed. Check which before treating results as complete
5. DeepResearch is async. Poll `valyu_deepresearch_status` rather than waiting in one call

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