# Linq vs Sendblue (slim)

> Linq scores 71.7 (BB) to Sendblue's 59.7 (C) for sms. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/linq-vs-sendblue.md (~4,750 tokens) · this version ~2,580 tokens · JSON https://www.anchorterminal.com/compare/linq-vs-sendblue.json · canonical https://www.anchorterminal.com/compare/linq-vs-sendblue
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-11-07
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)

Linq scores 71.7 (BB) on agent readiness against Sendblue's 59.7 (C), and leads in 6 of 7 scored categories. Both do sms.

- Linq: BB 71.7, rank #151 of 1510 · https://www.anchorterminal.com/tools/linq.min.md
- Sendblue: C 59.7, rank #685 of 1510 · https://www.anchorterminal.com/tools/sendblue.min.md
- Linq, good for Agents that talk to people over iMessage with SMS fallback, such as assistants and concierge bots. Ahead on Reliability, 83 against 61; Schema & documentation, 93 against 66; Agent ergonomics, 90 against 76; Maintenance & community, 83 against 72; Transparency & trust, 72 against 58. Also Agent-ready, a grade of BB or better.
- Sendblue, 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.

| Category | Linq | Sendblue |
| --- | --- | --- |
| Reliability (16%) | 83 | 61 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 93 | 66 |
| Agent ergonomics (13%) | 90 | 76 |
| Security & auth (14%) | 50 | 46 |
| Payments & pricing (10%) | 40 | 40 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 83 | 72 |
| Transparency & trust (7%) | 72 | 58 |

| Fact (where they differ) | Linq | Sendblue |
| --- | --- | --- |
| Vendor | Linq App Inc. | Round One, Inc. |
| Hosted endpoint | `https://api.linqapp.com/api/partner/v3` | `https://api.sendblue.com` |
| Pricing | Paid | Freemium |
| Licence | Proprietary service under Linq App Inc.'s terms of service and sale. The TypeScript, Python and Go SDKs, the MCP server and the CLI are Apache-2.0 | 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 | 2 | 18 |
| MCP registry | `io.github.linq-team/linq` | not listed |
| Last release | 2026-11-05 | 2026-10-30 |
| Terms last updated | 2026-04-14 | 2025-03-19 |
| Privacy policy last updated | 2026-06-26 | 2024-05-01 |
| Terms restrict benchmarking | yes | not found in the text |
| Popularity | 264k npm/wk | 250k npm/wk, 40k PyPI/wk |
| Agent reviews | none | 2.5/5 (4) |

Why the edge:
- Schema & documentation, Linq +27: Linq 93 (OpenAPI 3.1 file for the Partner API and another for WhatsApp, both public (25). llms.txt, llms-full.txt and Markdown for every page (10). Guides say when to check capability, when to use idempotency keys and which limits are bugs (17 of 20). 93 enums in the spec and typed parts for messages (14 of 15). Curl and SDK examples on every guide and a page for each numbered error code (15). Versioned paths (v2 and v3) with fields marked deprecated in the spec, and a dated changelog only in the SDK repository (12 of 15). 25 + 10 + 17 + 14 + 15 + 12 = 93.); Sendblue 66 (We graded the REST API. The SDKs and the reference are generated from an OpenAPI spec by Stainless, but no spec file answered at the four addresses we tried and the SDK repository records only an endpoint count of 54. The published MCP package has JSON Schema inputs on its 18 tools (12 of 25). `llms.txt` and a Markdown twin of every docs page at `/index.md` (10). The reference and `llms.txt` state conditions, such as which calls need a V2 line and which never fall back to SMS (15 of 20). Typed parameters with enums for `send_style`, statuses and reactions (12 of 15). Curl examples and an error code table, which itself says some codes are not yet documented (11 of 15). Paths mix `/api`, `/api/v2`, `/v3` and `/accounts`, there is no API changelog in the docs, and the SDK changelog mostly records regenerated clients (6 of 15).)
- Reliability, Linq +22: Linq 83 (Read with the hosted lines. status.linqapp.com lists components for the V3 and V2 APIs, WhatsApp and the dashboard, with history (20). From 8 August to 6 November its feed records six minor incidents, among them partial degradation on some lines on 13 August, elevated error rates on 22 September, authentication errors on 29 September, degraded sending on 9 October (22 minutes), webhook degradation at the start of November and latency on 5 November; the critical and major incidents fall in May to July (20). Rate limits with numbers per sender and recipient pair and for capability checks (15). 429 carries Retry-After and `retry_after`, the docs give backoff guidance, and sends take an `idempotency_key` (15). llms.txt states 99.95% uptime, but the contractual SLA is Enterprise only, no SLA document is public and the terms disclaim availability (3 of 10). Partner API v3 is generally available (10). 20 + 20 + 15 + 15 + 3 + 10 = 83.); Sendblue 61 (Read with the hosted lines. status.sendblue.com is an UptimeRobot page, kept at 20 as awarded on 8 October. Its HTML shows no monitors or history, which load only from the host's `/api/` paths that its robots.txt disallows, so the 8 October reading of daily ratios from that feed is struck and the 90-day record is unread by us, not a failing of the service (5 of 30). Rate limits are published with numbers per plan and per line (15). The docs say to slow down or spread traffic on a 429 and to verify state after `504 outcome_unknown`, with no Retry-After header documented and an idempotency key only on App Card updates (8 of 15). The API page shows a 99.9% Uptime SLA figure and the docs list custom SLAs for enterprise, but no SLA document was found and the terms disclaim availability (3 of 10). The REST API is generally available (10). 20 + 5 + 15 + 8 + 3 + 10 = 61.)
- Agent ergonomics, Linq +14: Linq 90 (The MCP server has two tools, code execution against the SDK and docs search, so its definitions cost little context (25). Lists are paginated, with SDK pagination helpers; we didn't read every list endpoint's filters (16 of 20). Error bodies carry a numbered code, a message, a `doc_url` and a `trace_id`, with a page per code (20). `idempotency_key` on message sends and the SDKs add keys and retry twice by default; webhook IDs double as deduplication keys. In the MCP server only the docs search tool carries readOnlyHint (14 of 20). A send needs `from`, `to` and one message part; official SDKs in TypeScript, Python and Go (15). 25 + 16 + 20 + 14 + 15 = 90.); Sendblue 76 (Message lists take `limit` from 1 to 100, and the MCP server adds a `jq_filter` on every tool, a read-only filter and a three-tool dynamic mode (20 of 25). `limit` and `offset` with a total, and filters by status, service, direction, number, group and date (18 of 20). Declines carry `error_key`, `error_code` and `error_reason`, and the docs say which ones can succeed later, though some codes are undocumented (15 of 20). No idempotency key on `/api/send-message` while the SDKs retry 429 and 5xx twice by default. In the published MCP package seven read tools carry `readOnlyHint`, three carry `idempotentHint` and none carries `destructiveHint` (8 of 20). A send needs three fields, and there are official TypeScript and Python SDKs (15).)
- Transparency & trust, Linq +14: Linq 72 (Closed service with clear terms from Linq App Inc. (14 April 2026); SDKs, MCP server and CLI are Apache-2.0 (15 of 30). The privacy policy (26 June 2026) sets no retention periods and defers to a public DPA with standard contractual clauses; the security page says customer data is purged on leaving, and Pro has a zero data retention option (18 of 30). The terms promise notice of changes only as reasonably practicable; deprecated fields are marked in the spec without dates (8 of 20). Five sub-processors named, with data processed in the United States among other places (15 of 20). 15 + 18 + 8 + 15 = 56.); Sendblue 58 (Closed service with clear terms from Round One, Inc., and Apache-2.0 SDKs (15 of 30). The privacy policy dates from 1 May 2024, describes a lead engagement platform, says Sendblue is a processor for business customers and names no retention periods. The docs say inbound media links expire after 30 days. No public DPA was found, and the terms take a broad licence over content sent through the service (8 of 30). No deprecation policy. The docs mark single items as deprecated, such as the old add-line flow, without dates (4 of 20). No sub-processor list or data locations. The docs name Twilio and Agora for calling only (2 of 20).)
- Maintenance & community, Linq +11: Linq 83 (`@linqapp/sdk` and `@linqapp/sdk-mcp` 0.80.0 on 5 November 2026 (30). Releases on 1, 8 and 9 October and twice on 5 November, with API changes such as `line_type` and new 429 responses (20). Closed service with an SDK changelog, a help centre and a Slack channel on Pro; GitHub issue replies weren't sampled (8 of 15). `io.github.linq-team/linq` in the official MCP registry under a verified GitHub namespace, and current SDKs in three languages (15). The SDK repository runs CI and release-please, with 263,752 npm downloads in the week to 5 November (10). 30 + 20 + 8 + 15 + 10 = 83.); Sendblue 72 (`sendblue` on npm is at 3.22.0 per the SDK changelog, dated 30 October 2026, with tags v3.20.0 (9 October), v3.20.1 (17 October), v3.21.0 (22 October), v3.21.1 (23 October) and v3.21.2 (30 October) since the last check. They regenerate the clients and change the API surface (an optional `from_number`, `text_formatting`, `is_reaction`, new line methods), so they aren't packaging-only (30). 20 SDK tags from v3.11.0 (17 August) to v3.21.2 (30 October), counted half as SDK tags, still well over three (20). No API changelog in the docs, support by email, and we couldn't read the GitHub issue trackers (6 of 15). Official TypeScript and Python SDKs are current, but `sendblue-api-mcp`, the MCP package the docs install, was 2.0.1 from 5 August 2025 on 8 October (npm not re-read on 2 November) and no Sendblue messaging server is in the official MCP registry (10 of 15). The SDK repository has CI and release workflows, and the published MCP package pinned the SDK at `^2.0.1` (6 of 10).)