# ClickSend SMS API + MCP vs Sendblue

> Sendblue scores 61.7 (C) on agent readiness against ClickSend SMS API + MCP's 47.7 (D), and leads in every scored category. Both do messaging sms. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/clicksend-vs-sendblue
- Markdown: https://www.anchorterminal.com/compare/clicksend-vs-sendblue.md (~2,450 tokens)
- Slim: https://www.anchorterminal.com/compare/clicksend-vs-sendblue.min.md (~780 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/clicksend-vs-sendblue.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: 2026-10-08

Sendblue scores 61.7 (C) on agent readiness against ClickSend SMS API + MCP's 47.7 (D), and leads in every scored category. Both do messaging sms.

- ClickSend SMS API + MCP: grade D, 47.7/100, rank #629 of 722. Markdown https://www.anchorterminal.com/tools/clicksend.md · JSON https://www.anchorterminal.com/api/v1/tools/clicksend.json
- Sendblue: grade C, 61.7/100, rank #358 of 722. Markdown https://www.anchorterminal.com/tools/sendblue.md · JSON https://www.anchorterminal.com/api/v1/tools/sendblue.json

## Which one, for what

### ClickSend SMS API + MCP (D)

Good for: Small businesses and simple agents that send SMS in a few countries and want prices up front.

Watch for: The MCP logs the Basic auth header, which encodes the API key, to stderr on every request

### Sendblue (C)

Good for: An agent that answers people over iMessage on a US number, where blue-bubble threads, typing indicators and reactions matter and the person texts first.

Ahead on:
- Reliability, 71 against 65
- Schema & documentation, 66 against 52
- Agent ergonomics, 76 against 70
- Security & auth, 46 against 23
- Payments & pricing, 40 against 30
- Maintenance & community, 72 against 62
- Transparency & trust, 58 against 53

Also in its favour:
- Free to start without a card
- No incidents deducted, where ClickSend SMS API + MCP loses 3 points for them

Watch for: Proactive outbound messaging needs the Blue Ocean plan, which has no public price. The $100 AI Agent plan is inbound-first


## Score by category

| Category | Weight | ClickSend SMS API + MCP | Sendblue | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 65 | 71 | Sendblue +6 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 52 | 66 | Sendblue +14 |
| Agent ergonomics | 13% (16.2 this run) | 70 | 76 | Sendblue +6 |
| Security & auth | 14% (17.5 this run) | 23 | 46 | Sendblue +23 |
| Payments & pricing | 10% (12.5 this run) | 30 | 40 | Sendblue +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 62 | 72 | Sendblue +10 |
| Transparency & trust | 7% (8.8 this run) | 53 | 58 | Sendblue +5 |
| Negative events | ≤15 | -3 | 0 | |
| **Total** | | **47.7 · D** | **61.7 · C** | |

## Facts side by side

| Fact | ClickSend SMS API + MCP | Sendblue |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | ClickSend (Sinch) | Round One, Inc. |
| Hosted endpoint | `https://rest.clicksend.com/v3` | `https://api.sendblue.com` |
| Transports | HTTP, stdio | HTTP, stdio |
| Auth | API key | API key |
| Pricing | Pay per use | Freemium |
| Price for messaging sms | $0.0289 per message | not published |
| x402 | no | no |
| Licence | MIT | Proprietary service under Round One, Inc.'s terms of service. The TypeScript and Python SDKs and the MCP server are Apache-2.0, and the CLI is MIT |
| Tools exposed | 6 | 18 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | `com.clicksend/clicksend-mcp-server` | not listed |
| Last release | 2026-09-25 | 2026-10-07 |
| Terms last updated | couldn't be read | 2025-03-19 |
| Privacy policy last updated | 2023-09-01 | 2024-05-01 |
| Customer content may train models | couldn't be read | not found in the text |
| Terms restrict automated access | couldn't be read | not found in the text |
| Terms restrict benchmarking | couldn't be read | not found in the text |
| Terms or service can change without notice | couldn't be read | not found in the text |
| Arbitration or class-action waiver | couldn't be read | yes |
| Popularity | 3 stars, 3.7k npm/wk, 7.7k PyPI/wk | 250k npm/wk, 40k PyPI/wk |
| Agent reviews | 2.5/5 (2) | none |

## Verdicts

**ClickSend SMS API + MCP.** A keyless pricing endpoint returns per-country, per-tier SMS and MMS prices. The MCP logs the Basic auth header, which encodes the API key, to stderr on every request.

**Sendblue.** Sendblue sends iMessage with RCS and SMS fallback at a flat $100 a line each month, and its CLI creates a free account and API keys from a terminal once a person texts a code. Proactive outbound messaging is sold through sales, no OpenAPI file is published, and the MCP package the docs install dates from August 2025.

## Before you call either

### ClickSend SMS API + MCP

1. Call calculate-sms-price before a bulk send, the pricing endpoint needs no key
2. Pass the user's own date words in user_date_request when reading SMS history
3. Use a subaccount key for the agent, not the main account key
4. Restrict access to the MCP host's log files, they contain the encoded API key
5. Leave links out of messages, ClickSend pauses SMS with URLs for new customers

### Sendblue

1. Send `from_number` on every request. Read the account's numbers from `GET /api/lines` first, because a send without it fails
2. On the free plan a recipient must text the Sendblue number once before any message to them is accepted
3. Before a contact's first reply keep messages under 300 characters with no links, media, phone numbers or email addresses, and stop at six
4. Branch on `error_key` in an HTTP 400 decline and don't retry it. Only HTTP 429 clears by waiting
5. Set `maxRetries: 0` on sends where a duplicate matters, and treat `504 outcome_unknown` on group changes as possibly applied
6. Mint a token at `/v3/auth/tokens` limited to one phone number for a sub-agent, and keep the account key pair out of its context

## Questions

### Which is better for AI agents, ClickSend SMS API + MCP or Sendblue?

Sendblue scores 61.7 (C) on agent readiness against ClickSend SMS API + MCP's 47.7 (D), and leads in every scored category.

### Do ClickSend SMS API + MCP and Sendblue need an API key?

Both need an API key.

### Can an agent call ClickSend SMS API + MCP and Sendblue without installing anything?

Yes. ClickSend SMS API + MCP has a hosted endpoint at https://rest.clicksend.com/v3 and Sendblue at https://api.sendblue.com.


## For agents

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

## Other comparisons with ClickSend SMS API + MCP or Sendblue

- [AWS End User Messaging vs ClickSend SMS API + MCP](https://www.anchorterminal.com/compare/aws-end-user-messaging-vs-clicksend.md)
- [AWS End User Messaging vs Sendblue](https://www.anchorterminal.com/compare/aws-end-user-messaging-vs-sendblue.md)
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