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  • What: The account-wide CPS and concurrency limits your trunks draw on, plus the per-trunk and resource limits.
  • When: Check when sizing trunks, or when calls fail with hangup cause 5180 or 5190.
Your account has two call capacity limits, and both apply at the same time. CPS (calls per second) caps how fast you can start new calls. Concurrency caps how many calls can be active at once. Both limits are account-wide: your trunks draw on the same pool as your Voice API traffic, not a separate SIP Trunking allowance.

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Your call capacity limits

Your limits depend on your data region and, in the US data region, on your plan and lifetime spend.
Outbound CPS and concurrency are single account-wide pools shared by Voice API and SIP Trunking. An account with 2 outbound CPS can start two outbound calls per second in total, whichever product they go out on. An account with 50 concurrent calls can hold 50 calls in total across both products.
Free Tier is not a plan you select. Every US data region account starts there and moves to Professional on its first payment. US data region accounts created before October 1, 2026 are not on the plan-based limits in the table. They have custom limits, set per account based on usage. In the India data region, Plivo sells capacity as concurrency. Professional accounts start at 50 concurrent calls. Enterprise accounts purchase the concurrency they need, and the limit and its price are set by the contract. Your CPS is set from your concurrency limit, so when your concurrency limit changes, your CPS changes with it.

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Trunk-level CPS

Each outbound trunk also has its own CPS, allocated from the account pool. Both levels are enforced. You cannot exceed the account CPS limit by spreading traffic across trunks. Inbound trunks have no CPS limit of their own.

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What counts toward your concurrency limit

Concurrency is the number of active calls on your account at any point in time, including calls that are still being set up. Every PSTN call leg counts, inbound and outbound, across SIP Trunking and Voice API. Plivo runs the same concurrency check for SIP Trunking calls as for Voice API calls. SIP-to-SIP calls and WhatsApp calls do not count toward your account concurrency limit.

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India data region: 140-series and 160-series numbers

Calls placed from 140-series and 160-series numbers draw on a separate concurrency allocation for that series, not on your account concurrency limit. Calls from your other numbers are not affected when a series limit is reached. A SIP Trunking call rejected at a series limit carries hangup cause 5190 (concurrent_call_limit_exceeded), the same as an account-level breach. Plivo sets the 140-series and 160-series allocation on your account when you provision those numbers. To check or change it, ask Buddy, Plivo’s in-console chat agent, under Organization settings > Account limits in the Plivo console, or contact your account manager.

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What happens when you exceed a limit

SIP Trunking rejects every call above a limit. It never queues.
SIP Trunking never queues. Every call above a limit fails instantly — no ring, no connection, no grace period. As soon as your rate or active call count drops below the limit, new calls are accepted again.
Every rejected SIP Trunking call appears in Logs > SIP Trunking with its hangup cause, so you can measure the impact directly. Hangup causes 5030, 5180, and 5190 are the same in every data region. See Zentrunk hangup codes for the full list.

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Concurrency alert emails

When calls are rejected for a concurrency breach, Plivo emails your account owner with the time window, the limit that was reached, and what to do next. Plivo sends at most one alert every 24 hours per limit.

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Trunk and resource limits

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Checking your limit and usage

  1. To see your current concurrency limit, go to Organization settings > Account limits in the Plivo console.
  2. To see your usage, go to Logs > Voice > Export > Export Concurrency Data. The export gives minute-level concurrent call data for up to 30 days.
The export counts every concurrent call on your account: SIP Trunking and Voice API, inbound and outbound. Logs > SIP Trunking shows your trunk call activity, including rejected calls, for the last 30 days.
Rule of thumb: if your 30-day peak exceeds 80% of your limit, review your capacity before you start seeing failures. Pace your PBX or dialer within your CPS, stagger bulk campaigns rather than launching them at once, and retry after a short delay when a call is rejected.

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Increasing your limits