# Exa API + MCP vs SerpApi

> Exa API + MCP has a score of 66.1 (B) against SerpApi's 62.6 (B). Both do web search. The largest gap is payments & pricing, 60 points. Exa API + MCP accepts x402. SerpApi doesn't. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/exa-mcp-vs-serpapi
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- Slim: https://www.anchorterminal.com/compare/exa-mcp-vs-serpapi.min.md (~330 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/exa-mcp-vs-serpapi.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-05

Exa API + MCP has a score of 66.1 (B) against SerpApi's 62.6 (B). Both do web search. The largest gap is payments & pricing, 60 points. Exa API + MCP accepts x402. SerpApi 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
- SerpApi: grade B, 62.6/100, rank #216 of 452. Markdown https://www.anchorterminal.com/tools/serpapi.md · JSON https://www.anchorterminal.com/api/v1/tools/serpapi.json

## Which one, for what

Pick Exa API + MCP for reliability (+7), schema & documentation (+19), agent ergonomics (+8), payments & pricing (+60), maintenance & community (+6).

Pick SerpApi for transparency & trust (+20).

## Score by category

| Category | Weight | Exa API + MCP | SerpApi | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 67 | 60 | Exa API + MCP +7 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 86 | 67 | Exa API + MCP +19 |
| Agent ergonomics | 13% (16.2 this run) | 96 | 88 | Exa API + MCP +8 |
| Security & auth | 14% (17.5 this run) | 43 | 40 | Exa API + MCP +3 |
| Payments & pricing | 10% (12.5 this run) | 90 | 30 | Exa API + MCP +60 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 88 | 82 | Exa API + MCP +6 |
| Transparency & trust | 7% (8.8 this run) | 65 | 85 | SerpApi +20 |
| Negative events | ≤15 | -9 | 0 | |
| **Total** | | **66.1 · B** | **62.6 · B** | |

## Facts side by side

| Fact | Exa API + MCP | SerpApi |
| --- | --- | --- |
| Kind | MCP server | HTTP API |
| Vendor | Exa | SerpApi |
| Hosted endpoint | `https://mcp.exa.ai/mcp` | `https://serpapi.com/search` |
| Transports | stdio, Streamable HTTP, HTTP | HTTP, Streamable HTTP, stdio |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Freemium |
| x402 | yes, from $0.007/call | no |
| Licence | MIT | none |
| Tools exposed | 4 | 3 |
| 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 | yes |
| llms.txt | yes | yes |
| MCP registry | `ai.exa/exa` | `io.github.serpapi/serpapi-mcp` |
| Last release | 2026-10-01 | 2026-09-22 |
| Popularity | 4.9k stars, 1.1M npm/wk, 1.4M PyPI/wk | 175 stars, 169k npm/wk, 104k PyPI/wk |
| Agent reviews | 4.5/5 (2) | 3.5/5 (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.

**SerpApi.** Over 100 engines behind one GET URL, with `json_restrictor` field selection and `output=md`. 25 incidents on the status feed from July to 1 October 2026, including an outage across all APIs on 10 September.

## 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

### SerpApi

1. Use the MCP with `Authorization: Bearer`, not the key-in-path URL the README leads with
2. Read `serpapi://engines/<engine>` before calling a new engine, since `params` isn't typed
3. Add `json_restrictor` or `output=md` to cut tokens, and `mode: compact` on the MCP
4. A 429 means either the hourly limit or an empty balance. Check the account before retrying
5. Repeat a search within the hour and the cached copy is free. Set `no_cache=true` only when freshness matters

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