ZeroSettle vs Linq: iMessage API price, SLA and features (2026)

How we compared ZeroSettle and Linq

We compared ZeroSettle and Linq on price and refunds, published reliability, channels, rules for messaging people first, features, developer experience, AI, and procurement paperwork, using each company's own public pages as of October 8, 2026. ZeroSettle is an iMessage API: a real phone number on real iMessage, running on Apple hardware we operate for you, that your code texts customers from and hears back on through a bearer token and signed webhooks. Linq describes itself as "an iMessage API to send and receive iMessages, RCS, & SMS."

For background, see what an iMessage API is, 14 iMessage API options compared and all ZeroSettle comparisons.

ZeroSettle vs Linq at a glance

Linq offers more channels, features and procurement paperwork; ZeroSettle costs less than Linq Pro for one number and hosts an AI agent.

ZeroSettle cells come from its API docs, homepage and terms. "Not published": no public page found.

How do ZeroSettle and Linq prices and trials compare?

For one number, ZeroSettle Pro is $49 a month and Linq Pro starts at $260, so a year costs $588 against at least $3,120 at list price. Linq lets you try first; ZeroSettle has no trial but refunds instead.

• Linq Hobby ($0/mo): a free Shared Line through Linq's CLI, "with a 20 contact limit, designed for hobbyist and personal projects"; each contact "must text the Linq Number first".
• Linq Pro ("Starting at $260/mo"): adds group messaging, payments, iMessage Apps, live location and managed load balancing, with a 7-day trial and "No credit card required to sign up". The page does not say whether $260 covers one line or several.
• Linq Enterprise (custom): volume discounts, "Contractual SLAs", forward-deployed engineers and SSO.
• ZeroSettle Pro ($49/month): one number to start (more can be added), "No setup fee · Cancel anytime", 5 new contacts a day, unlimited messages with people who message you first, 1,000 AI credits a month. Numbers can sell out (there is a waitlist).
• ZeroSettle Growth ("From $599/mo"): "3+ phone numbers" that work as one, 5,000 AI credits a month and dedicated support, set up after a demo.

On refunds, ZeroSettle's docs say ask within 30 days "and you are refunded in full and the subscription is cancelled" (AI credit packs excluded). Linq's Terms (effective April 14, 2026): "Unless otherwise stated, fees are non-refundable." More providers are in iMessage API pricing compared.

What do ZeroSettle and Linq publish about reliability?

Linq publishes more: it advertises 99.95% uptime with a contractual SLA and runs a public status page with an incident history. ZeroSettle shows "99.9% uptime" on its homepage and offers no SLA.

Linq

• Linq's iMessage API page says: "99.95% uptime backed by the only contractual SLA in the industry". Its pricing page lists "Contractual SLAs" under Enterprise only.
• Linq's status page showed "Linq V3 API" at 99.93% for July to October 2026 (viewed October 8, 2026), with incidents or maintenance on July 23 and 27, August 8, 13 and 22, and September 22 and 29.
• Linq's Terms: "LINQ DOES NOT WARRANT THAT MESSAGES WILL BE DELIVERED, RECEIVED, READ, OR TIMELY."

ZeroSettle

• ZeroSettle's homepage shows "99.9% uptime": a stat, not an SLA. ZeroSettle publishes no status page.
• If Apple flags a number, ZeroSettle's homepage says "we replace the number right away at no extra charge". Your API token, webhook and code stay the same; recipients see a new number.
• ZeroSettle's terms: "delivery of any particular message or feature is not guaranteed", and ZeroSettle "does not warrant that the services will meet your requirements or that their operation will be uninterrupted or error-free".

Over a 30-day month, 99.9% allows about 43 minutes of downtime and 99.95% about 22. See what 99.9% uptime means for an iMessage API.

How do ZeroSettle and Linq outbound rules compare?

Both set a daily threshold per line for messaging people first. ZeroSettle's are hard caps that refuse the send with 429 new_contact_limit; Linq's is a health signal that moves the line to AT_RISK, which Linq calls "a warning, not a hard stop".

Sources: ZeroSettle's limits and compliance docs; Linq's Phone Reputation docs. On both, re-messaging an existing conversation does not count as new.

The limit math for 120 people who asked to hear from you, in one day:

• ZeroSettle Pro, one number: 5 a day, so 120 takes 24 days; this volume is what Growth is for.
• ZeroSettle Growth, three numbers: 150 a day fits all 120, but at 3 new contacts per rolling 15 minutes per number (9 per window across three), the last first message goes out about 3 hours 15 minutes after the first.
• Linq: staying under roughly 50 per line takes at least three lines, 40 each, and Linq's docs say to "spread the first touch across days" for a large list.

How do features and developer experience compare?

Linq has the wider feature set, official SDKs and fallback; ZeroSettle has a smaller one-to-one iMessage surface, plus a hosted AI agent and a live event stream. Both have tooling for AI coding agents.

What Linq offers that ZeroSettle does not

• Group chats with mentions, polls, message effects, and edits (up to 5 times within 15 minutes).
• Video, documents and other files up to 100 MB. ZeroSettle sends photos (5 MB) and voice messages (6 MB) only.
• Apple Pay payment requests, iMessage Apps, and location sharing the recipient accepts.
• Read receipts. ZeroSettle's API reports only that a message left the line (message.sent) or failed.
• SDKs for TypeScript, Python and Go, and a separate WhatsApp API.
• Managed load balancing that "moves the recipients onto a fresh line when their current one can't send".

What ZeroSettle adds

• A hosted AI agent, "Managed by AI Agent" (Beta): "our hosted agent answers every inbound text on the group's lines, from your business context." See how the hosted agent works.
• A live stream (server-sent events) of messages, webhook deliveries, typing, opt-outs and AI credits at /api/imessage/stream, opened with a 5-minute token from GET /api/imessage/stream-token.

For AI coding agents, ZeroSettle's MCP connector (Claude, Cursor, Grok) signs you up, mints your server's API key, and registers and tests your webhook; it is a setup tool, not a way to message customers. Linq's plugin (Claude Code, Cursor, Codex) can sign you up and provision a number through Linq's CLI, search its docs and run code against your account.

Webhooks side by side

Both sign with HMAC-SHA256 and wait 10 seconds for a response; they differ most in how long they retry.

ZeroSettle's last retry comes about 26 seconds after the first attempt, plus any timeouts, so a receiver down for a few minutes misses those events; recover them by paging GET /api/imessage/messages?after_id=….

ZeroSettle signs "<t>." + raw body. This Python check is from the webhook docs (Node is there too):

import hmac, hashlib, time

def verify(secret: str, header: str, raw_body: bytes, tolerance: int = 300) -> bool:
    try:
        parts = dict(p.split("=", 1) for p in header.split(","))
        t, v1 = int(parts["t"]), parts["v1"]
    except Exception:
        return False
    if abs(time.time() - t) > tolerance:
        return False
    expected = hmac.new(secret.encode(), f"{t}.".encode() + raw_body, hashlib.sha256).hexdigest()
    return hmac.compare_digest(expected, v1)

Verify the raw bytes before parsing JSON. The secret is shown once and rotates when you register again. More in how ZeroSettle webhooks work.

When ZeroSettle is not a fit: when Linq is the better choice

Linq is the better choice when you need reach beyond iMessage, pooled lines, rich iMessage features or procurement paperwork:

• Android and other non-Apple recipients. Linq falls back to RCS and SMS; ZeroSettle has "no SMS or email fallback" (SMS fallback is on its roadmap).
• Many lines routed for you, with failover off a line that can't send.
• Group chats, polls, effects, video, files, payments or read receipts. ZeroSettle is one-to-one, with photos and voice messages.
• Procurement: SOC 2 Type I and Type II reports, plus SSO and contractual SLAs on Linq Enterprise.
• Trying first: the free Hobby tier and a no-card Pro trial.
• Your CRM: Linq Blue works inside GoHighLevel, Salesforce and HubSpot; ZeroSettle connects natively to Close, with Salesforce still coming soon (see iMessage in your CRM).
• Longer webhook retries: 30 minutes, against about 26 seconds.
• More first messages per line on an entry plan: roughly 50 a day before AT_RISK, against 5 on ZeroSettle Pro (50 needs Growth).

When ZeroSettle is the better choice

ZeroSettle fits a team that wants one production iMessage number for $49 a month, or texts answered without running a server.

• Price for one number: $49/month against Linq Pro's "Starting at $260/mo".
• No server for the AI: the hosted agent (Beta) answers from your business context and uses one AI credit per text; Pro includes 1,000 a month.
• Self-serve start: sign up, set the name and photo, test and subscribe from the console or your AI coding agent, subject to availability. Linq's docs say its numbers are provisioned by your Linq representative.
• Refunds: a 30-day money-back guarantee on the subscription, where Linq's fees are "non-refundable" unless stated otherwise.
• A small surface: a bearer token, POST /api/imessage/send, reactions, typing, one signed webhook and a live stream, no SDK needed.

At parity: both sign webhooks with HMAC-SHA256, show a branded name and photo, and block a contact who texted STOP on every line on the account. The details differ. ZeroSettle shares the name and photo automatically with each conversation's first message; Linq has you call a contact-card share endpoint per chat. Linq lifts a STOP block when the contact sends anything that isn't a stop keyword; ZeroSettle reopens only on START (or unstop), or when ZeroSettle clears it on request.

Weighing Sendblue too? See ZeroSettle vs Sendblue. Or get a ZeroSettle number, read the iMessage API docs or see ZeroSettle's plans.

How we checked

We read every page cited here on October 8, 2026, re-read them on October 9, and tested nothing that needs a Linq account.

• Linq: its pricing, iMessage API, CLI, security and status pages, its Terms (effective April 14, 2026), the Linq Blue help article, and the docs pages listed under Sources.
• ZeroSettle: its API docs, homepage and iMessage API Terms (last modified September 28, 2026).

We refresh this comparison quarterly and log changes in the changelog.