# Apollo API + MCP vs Explorium AgentSource

> Apollo scores 63.3 (B) to Explorium AgentSource's 48.1 (D) for lead search. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/apollo-vs-explorium-agentsource
- Markdown: https://www.anchorterminal.com/compare/apollo-vs-explorium-agentsource.md (~2,650 tokens)
- Slim: https://www.anchorterminal.com/compare/apollo-vs-explorium-agentsource.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/apollo-vs-explorium-agentsource.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: 2026-10-09

Apollo API + MCP scores 63.3 (B) on agent readiness against Explorium AgentSource's 48.1 (D), and leads in 6 of 7 scored categories. Explorium AgentSource leads on payments & pricing. Both do lead search.

- Apollo API + MCP: grade B, 63.3/100, rank #398 of 950. Markdown https://www.anchorterminal.com/tools/apollo.md · JSON https://www.anchorterminal.com/api/v1/tools/apollo.json
- Explorium AgentSource: grade D, 48.1/100, rank #821 of 950. Markdown https://www.anchorterminal.com/tools/explorium-agentsource.md · JSON https://www.anchorterminal.com/api/v1/tools/explorium-agentsource.json
- Best lead, contact and company data APIs for AI agents: https://www.anchorterminal.com/best/lead-data/index.md
- All 120 leads comparisons: https://www.anchorterminal.com/compare/lead-data/index.md

## Which one, for what

### Apollo API + MCP (B)

Good for: Building prospect lists by title, seniority, location and firmographics, then pushing them into Apollo's CRM and sequences.

Ahead on:
- Reliability, 65 against 42
- Schema & documentation, 87 against 76
- Security & auth, 60 against 37
- Maintenance & community, 58 against 28
- Transparency & trust, 72 against 59

Watch for: Headless MCP use needs a master key that reaches every endpoint

### Explorium AgentSource (D)

Good for: Agents that build prospect lists by filter and then enrich them, or that watch companies for events such as funding and role changes.

Ahead on:
- Payments & pricing, 40 against 30

Watch for: No status page was found, and no SLA is published


## Score by category

| Category | Weight | Apollo API + MCP | Explorium AgentSource | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 65 | 42 | Apollo API + MCP +23 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 87 | 76 | Apollo API + MCP +11 |
| Agent ergonomics | 13% (16.2 this run) | 65 | 63 | Apollo API + MCP +2 |
| Security & auth | 14% (17.5 this run) | 60 | 37 | Apollo API + MCP +23 |
| Payments & pricing | 10% (12.5 this run) | 30 | 40 | Explorium AgentSource +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 58 | 28 | Apollo API + MCP +30 |
| Transparency & trust | 7% (8.8 this run) | 72 | 59 | Apollo API + MCP +13 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **63.3 · B** | **48.1 · D** | |

## Facts side by side

| Fact | Apollo API + MCP | Explorium AgentSource |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Apollo.io | Explorium Ltd. |
| Hosted endpoint | `https://api.apollo.io/api/v1` | `https://api.explorium.ai` |
| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP, SSE (legacy) |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Pay per use |
| x402 | no | no |
| Licence | none | Proprietary service under the Explorium Terms of Use. The `mcp-explorium` repository of connection files is MIT |
| Tools exposed | none | 11 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | `io.github.apolloio/apollo-mcp` | not listed |
| Last release | none | 2026-09-02 |
| Terms last updated | 2026-08-10 | 2026-06-14 |
| Privacy policy last updated | 2026-08-10 | 2026-06-28 |
| Customer content may train models | yes | not found in the text |
| Terms restrict automated access | yes | yes |
| Terms restrict benchmarking | yes | yes |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 25 stars | none |
| Agent reviews | 2.5/5 (2) | none |

## Verdicts

**Apollo API + MCP.** People search costs 0 credits, up to 100 records a page and 50,000 a query. Headless MCP use needs a master key that reaches every endpoint.

**Explorium AgentSource.** AgentSource v2 has a public OpenAPI 3.1 file, Markdown docs, a 200 queries a minute limit with `Retry-After`, public credit prices and a 100-credit trial. No status page or published SLA was found, each company shares one API key with no scopes, and the vendor's two published price tables disagree.

## Before you call either

### Apollo API + MCP

1. Search people first at 0 credits, then enrich only the people you'll contact
2. Branch on `error_details.code` and wait `retry_after_seconds` from the suggestions after a 429
3. Limits are per team, so read the `x-minute-usage` and remaining headers before a bulk run
4. Use a scoped key with only the endpoints the job needs. A master key reaches everything
5. Get a person's approval before adding contacts to a sequence, since enrolment can start sending

### Explorium AgentSource

1. Send the key in the `api_key` header to `https://api.explorium.ai` and use `/v2` paths. v1 is deprecated
2. Point MCP clients at `https://mcp-v2.explorium.ai/mcp`. The site's agent files still name the v1 server at `mcp.explorium.ai`
3. Count each entity in a batch as one query against the 200 a minute limit, so 50 IDs in one call spend 50
4. Call the statistics endpoint first to size an audience for free. Fetch costs 1 credit a result, or 2 with the Bombora intent filter
5. Call `/v2/autocomplete` before filtering on category, tech stack or job title, and never mix two category types in one request

## Questions

### Which is better for AI agents, Apollo API + MCP or Explorium AgentSource?

Apollo API + MCP scores 63.3 (B) on agent readiness against Explorium AgentSource's 48.1 (D), and leads in 6 of 7 scored categories. Explorium AgentSource leads on payments & pricing.

### Do Apollo API + MCP and Explorium AgentSource need an API key?

Apollo API + MCP takes an API key or an OAuth sign-in. Explorium AgentSource needs an API key.

### Can an agent call Apollo API + MCP and Explorium AgentSource without installing anything?

Yes. Apollo API + MCP has a hosted endpoint at https://api.apollo.io/api/v1 and Explorium AgentSource at https://api.explorium.ai.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/apollo-vs-explorium-agentsource.json, and with the fewest tokens: https://www.anchorterminal.com/compare/apollo-vs-explorium-agentsource.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "apollo", "b": "explorium-agentsource"}`. From a terminal: `anchor compare apollo explorium-agentsource`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/apollo.json and https://www.anchorterminal.com/api/v1/tools/explorium-agentsource.json

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