AWS End User Messaging vs Linq

AWS End User Messaging 88

IAM with policies per action and resource ARN, service condition keys, temporary credentials and rotation. No secret travels in a URL (30). Policies can allow a single send action on one phone number or pool, and enforced spend limits, protect configurations and deletion protection bound what a credential can do. We found no read-only managed policy for the service and no confirmation step (15 of 20). API responses carry no third-party content. Inbound SMS and RCS go to an SNS topic or Connect Customer, not through API calls (10). CloudTrail logs control-plane calls as management events and the send actions as optional data events, and configuration sets publish per-message events (15). In scope for SOC 1, 2 and 3 (page updated 11 August 2026), with a vulnerability disclosure programme on HackerOne. aws.amazon.com's security.txt was renewed and now runs to 16 October 2027. No paid bug bounty was found, per the 8 October check, not re-read on 17 October. Read as the Amazon SES and Secrets Manager re-checks of 17 October read the same evidence (18 of 20).

Linq 50

Bearer API keys in a header, never in the query string, rotated or revoked in the dashboard, scoped to the account with no per-action or read-only scopes (20 of 30). Sandbox keys reach only verified handles, and the MCP server's --code-allow-http-gets and method allow and block lists limit its code tool; no approval step for sends (10 of 20). Inbound iMessage and SMS text reaches the agent, and no prompt-injection guidance was found in the docs or the MCP instructions (0 of 15). Every response carries a trace_id; no operator request log was found in the docs (5 of 15). SOC 2 Type II reports for 2024, 2025 and 2026 and a 2026 penetration test on request, a vulnerability disclosure policy open on the trust centre and SECURITY.md in the SDK repository; no security.txt or bug bounty (15 of 20). 20 + 10 + 0 + 5 + 15 = 50.

AWS End User Messaging 71

No dedicated MCP server. The AWS MCP Server with the aws-sms-voice skill covers guidance and can run the API calls. Send responses return only a MessageId, and 28 list actions take MaxResults (1 to 100) and NextToken (15 of 25). Describe actions take Filters and resource ID lists (16 of 20). Seven typed errors, with reason codes on conflicts (41 values), validation failures (43, plus the failing fields) and quota errors (28) (18 of 20). ClientToken on 15 create and request actions and DryRun on sends, but no idempotency token on SendTextMessage, SendMediaMessage or SendRcsMessage, so a retried send can go out twice (10 of 20). SendTextMessage requires only the destination number, and SDKs exist in every major language, but every call needs SigV4 and a first send needs a registered sender (12 of 15).

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.

AWS End User Messaging 85

Closed service under the AWS Customer Agreement and section 29 of the Service Terms, with Apache-2.0 SDKs (20 of 30). The guide says messages are processed and stored in the Region the customer picks and encrypted at rest with service-owned keys, and both the guide and the sub-processor page say downstream carriers may route messages through other regions. We found no retention period for message data (18 of 30). Amazon Pinpoint's end of support on 30 October 2026 carried dated notices (no new customers from 20 May 2025, end of support on 30 October 2026) that say these messaging APIs continue, and the document history dates each change. No general deprecation policy found (15 of 20). The sub-processor page, last updated 28 July 2026, names the entities that sell the service and promises 30 days' notice of new ones, but the downstream carriers are not named (17 of 20).

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.

AWS End User Messaging 73

AWS Health Dashboard with per-service, per-Region history (20). AWS's dashboard history file, re-read on 1 November, still lists AWS End User Messaging in the Middle East (UAE) me-central-1 and Middle East (Bahrain) me-south-1 multi-service events, open since 1 and 2 March 2026 at disruption status, with no update after 15 September. On that date, inside the 90-day window from 3 August, AWS said it can't restore resources and data hosted only in me-south-1 or the mec1-az2 zone. No other event in the window names the service, and the newest event in the file is an API Gateway one in us-west-2 posted on 30 October. One major event, read as the Amazon S3, Secrets Manager and Transcribe re-checks of 1 November read the same two events (10). Quotas page gives 1 request a second for most actions, SendTextMessage included (re-read 1 November), and the throughput page gives message parts a second by sender type (15). The API model marks ThrottlingException as retryable and 15 create and request actions take a ClientToken, but the send actions take no idempotency token and we found no backoff guidance in the guide pages we read (8). The AWS User Engagement SLA commits 99.9 per cent monthly uptime per Region and names AWS End User Messaging, per the 8 October check (10). Generally available (10). 20+10+15+8+10+10 = 73.

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.

AWS End User Messaging 30

No x402, MPP or L402 (0). Per-message prices by country and channel published without login, with a JSON feed for SMS (20). No SMS free allowance. Push is free for the first 1,000,000 notifications a month, and new AWS customers get up to $200 in Free Tier credits. The Free Tier FAQ says most new customers don't need a payment method, though AWS may still ask for one, so half, as on the Amazon SES re-check (10). A person signs up, and production access needs a support case per Region, so no autonomous route (0).

Linq 40

No x402, MPP or L402 (0). Public plan prices only, Hobby $0 and Pro from $260 a month, with no per-message fee (10 of 20). Hobby is free with no card, and the Pro trial needs no card (20). linq signup creates an account, an API key and a number from a terminal, but a person has to read back the emailed code, so half (10 of 20). 0 + 10 + 20 + 10 = 40.

AWS End User Messaging 88

No OpenAPI, but the Smithy models for both APIs are published in aws/api-models-aws, 110 operations for SMS and Voice v2 and 38 for Social Messaging (25). llms.txt for the user guide and the API reference, with Markdown twins of every page (10). The API reference explains each action, and the guide says when to use Notify and when standard sending. Few actions say when not to use them (12 of 20). 69 enumerated types, length limits and patterns on phone numbers and message bodies, required members marked (14 of 15). The guide carries CLI and Python examples and each action lists its errors, but the SendTextMessage reference page has no examples section (12 of 15). Versioned API (2022-03-31) and a dated document history, whose newest entry is still 22 September 2026 on 1 November (15).

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.