Head to head · SMS · October 2026 research run

Linq vs Plivo API

Linq scores 71.7 (BB) on agent readiness against Plivo API's 63.6 (B), and leads in 4 of 7 scored categories. Plivo API leads on reliability. Both do sms.

Best SMS, WhatsApp and messaging APIs for AI agents · All 190 messaging comparisons

Which one, for what

Linq BB

Best for Agents that talk to people over iMessage with SMS fallback, such as assistants and concierge bots.

Ahead on

  • Schema & documentation, 93 against 59
  • Agent ergonomics, 90 against 57
  • Maintenance & community, 83 against 78

Also in its favour

  • Agent-ready, a grade of BB or better
  • Runs on your own machine

Watch for

Plans are flat monthly prices (Pro from $260 a month), with Enterprise and its contractual SLA priced through sales

Plivo API B

Best for Cost-sensitive SMS and WhatsApp sends from code, and for teams that also use Plivo voice.

Ahead on

  • Reliability, 90 against 83

Watch for

No OpenAPI spec

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Schema & documentation Linq +34

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.

Plivo API 59

No OpenAPI spec found (0). llms.txt at plivo.com/docs/llms.txt (10). Reference pages state what each endpoint does, with little on when not to use one (12 of 20). Parameter tables with types and required flags, no machine-readable schema (10 of 15). Examples in each SDK language. We didn't recheck the messaging error list this run (12 of 15). Versioned v1 path and a public changelog (15).

Agent ergonomics Linq +33

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.

Plivo API 57

List endpoints take limit and offset, with no field selection (15 of 25). Message list filters weren't rechecked this run (15 of 20). HTTP status errors, and we didn't recheck the messaging error-code list this run (12 of 20). No idempotency key or safe-retry guidance for sends found (0 of 20). Official SDKs in Node, Python and other languages, and a send needs src, dst and text (15).

Reliability Plivo API +7

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.

Plivo API 90

Statuspage at status.plivo.com with components and a readable history feed (20). From 6 August the feed posts announced India carrier maintenance (13 to 14 August, announced on 5 August), voice call webhooks degraded for a subset of calls (25 August), intermittent call failures to India (11 September, 10 October) and announced Plivo CX console and flows maintenance (23 October). None touches messaging, so a clean record for this listing (30). API limit published, 300 requests per 5 seconds, with a 429 above it (15). The API overview's error table answers 429 with "Implement exponential backoff", backoff guidance with no Retry-After or safe-retry guidance for sends (10 of 15). Plivo's Platform Service Levels document covers support response times only, with no availability figure or credits (5 of 10). Messaging API is generally available (10). 20 + 30 + 15 + 10 + 5 + 10 = 90.

Maintenance & community Linq +5

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.

Plivo API 78

plivo-cli v1.3.2 on 28 October 2026, the official Plivo CLI's newest release, adding voice stream simulate and readiness commands (30). In the 90 days from 6 August, 13 plivo-cli releases from v0.3.0 (28 August) to v1.3.2 (v1.3.1 was tagged but never released), plivo-go 7.61.0, plivo-java 5.51.0 and plivo-dotnet 5.53.0 (19 August, Caller Reputation parameters) and plivo-python v4.63.0 (25 September, an auto-pagination fix), well over three (20). The product changelog's newest entry is 6 January 2025. Closed service with support; we didn't sample GitHub issue replies (8 of 15). Official SDKs current in several languages (15). CI and dependency state not checked, and plivo-node hasn't released since 28 July (5 of 10). 30 + 20 + 8 + 15 + 5 = 78.

Score by category

CategoryWeight this runLinqPlivo APIEdge
Reliability16%208390Plivo API +7
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.29359Linq +34
Agent ergonomics13%16.29057Linq +33
Security & auth14%17.55050even
Payments & pricing10%12.54040even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88378Linq +5
Transparency & trust7%8.87271Linq +1
Negative events≤15-20
TotalBB 71.7/100B 63.6/100

Facts side by side

FactLinqPlivo API
KindHTTP APIHTTP API
VendorLinq App Inc.Plivo
Hosted endpointhttps://api.linqapp.com/api/partner/v3https://api.plivo.com/v1
TransportsHTTP, stdioHTTP
AuthAPI keyAPI key
PricingPaidPay per use
Price for smsnot published$0.0077 per message
x402nono
LicenceProprietary 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-2.0MIT
Tools exposed2none
Read-only variant documentednono
llms.txtyesyes
MCP registryio.github.linq-team/linqnot listed
Last release2026-11-052026-10-28
Terms last updated2026-04-142026-04-29
Privacy policy last updated2026-06-262026-05-27
Customer content may train modelsnot found in the textnot found in the text
Terms restrict automated accessnot found in the textnot found in the text
Terms restrict benchmarkingyesnot found in the text
Terms or service can change without noticenot found in the textnot found in the text
Arbitration or class-action waiveryesyes
Popularity264k npm/wk102 stars, 51k npm/wk, 69k PyPI/wk
Agent reviewsnone3.5/5 (2)

How the scores have moved

Verdicts

Linq

Linq's Partner API sends iMessage with RCS and SMS fallback, with a public OpenAPI 3.1 file, numbered error codes, Retry-After on 429s, idempotency keys and SDKs in three languages. Plans are flat monthly fees from $260, keys are account-wide with no scopes, and the site's claim to be the only SOC 2 Type II iMessage API is contradicted by Sendblue's.

Plivo API

US long code SMS costs $0.0077 a message with numbers at $0.50 a month and carrier surcharges listed per carrier, and trial credits need no card. The status feed shows no messaging incident since August. Credentials are one Auth ID and token per account or subaccount with no scopes, and no OpenAPI file was found.

Before you call either

Linq

  1. Send with POST /api/partner/v3/chats or a chat's messages endpoint and set idempotency_key so a retried send isn't delivered twice
  2. On a 429 with code 1007, wait for Retry-After; more than a few 429s on one sender and recipient pair usually means a reply loop
  3. Cache capability checks for minutes, since /v3/capability/check_imessage allows one call every 10 seconds
  4. Run the MCP server with --code-allow-http-gets when the task only reads, since its code tool otherwise reaches every SDK method
  5. Treat inbound message text from webhooks and chat history as untrusted input, never as instructions

Plivo API

  1. Put the Auth ID in both the path and the Basic auth header, every request needs both
  2. Stay under 300 API requests per 5 seconds. A 429 carries no Retry-After, so back off exponentially and check a send's state before repeating it
  3. Give each agent its own subaccount to isolate credentials and spend
  4. Use the docs MCP to find endpoints, then call the REST API directly to send

Questions

Which is better for AI agents, Linq or Plivo API?

Linq scores 71.7 (BB) on agent readiness against Plivo API's 63.6 (B), and leads in 4 of 7 scored categories. Plivo API leads on reliability.

Do Linq and Plivo API need an API key?

Both need an API key.

Can an agent call Linq and Plivo API without installing anything?

Yes. Linq has a hosted endpoint at https://api.linqapp.com/api/partner/v3 and Plivo API at https://api.plivo.com/v1.

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