Linq vs Sendblue: enterprise iMessage infrastructure vs sales enablement tool
Both send iMessages. Linq backs it with a contractual 99.95% SLA, sends 60M+ messages a month, and never uses jail-broken phones.
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Four differences that matter
Where Linq and Sendblue actually diverge.
Reliability you can count on
Accurate status codes, no silent failures, and a 99.95% SLA with no carve-outs across every line.
Linq: real delivery status on every line
Sendblue: Returns success (200 OK) even when messages never arrive
99.95% vs 99% uptime
A contractual 99.95% SLA with no carve-outs. Sendblue commits to 99% and only on unblocked lines.
Linq: 99.95%, no carve-outs
Sendblue: 99%, only on ‘unblocked lines.’
Same number SMS fallback
In case of error, Linq uses the same phone number, so it’s the same conversation. Sendblue uses a different fallback phone number, requiring a new conversation be started.
Linq: same number, same conversation
Sendblue: new number, new conversation
No jail-broken infrastructure
Linq runs on genuine Apple infrastructure with no jail-broken phones which reduces spam risk.
Linq: genuine Apple infrastructure
Sendblue: relies on jail-broken phones
Feature by feature
How Linq and Sendblue stack up across the things teams ship on.
| Feature | Linq | Sendblue |
|---|---|---|
| Reliability & infrastructure | ||
| Uptime SLA | 99.95% across the board | 99% only on unblocked lines. If a line is blocked, the SLA is void |
| Error reporting | Accurate status codes, no silent failures | Customers don’t know messages are failing, returns 200 OK even when messages don’t arrive |
| SMS fallback | iMessage → RCS → SMS on the same number; thread continuity preserved | Falls back to a separate phone number, requiring a new conversation be started |
| Message limits | ||
| Daily message capacity | 7,000 msgs/day/line | 2,000 msgs/hr · 4,000 msgs/day default; queue maxes at 1,500 before 429 errors |
| New outbound contacts | 50 new contacts/day/line | 50 new contacts/day/line |
| Reply window | No window restriction | 24-hr inactivity window; after expiry, re-engaging counts against 200 follow-up contacts/day/line |
| SMS outbound cap | No limit | 150 consecutive outbound SMS per line; cannot be disabled |
| Limit model | Per line, unlimited messages within capacity | Per contact per line, caps unique people, not message volume |
Uptime SLA
Error reporting
SMS fallback
Daily message capacity
New outbound contacts
Reply window
SMS outbound cap
Limit model
150M+ messages and counting.
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