Syncing Quantities Into PSA Agreements: Pull, Push, or Both?

Of all the things an integration can do, syncing quantities is the one that touches money. The seat count your product reports ends up on an agreement line in the MSP's PSA, and from there on an invoice to their client. How that count moves from your system to theirs is a design decision worth getting right.

What Is the Difference Between Pull and Push Sync?

There are three common designs:

• Push: your product writes counts into the PSA, on a schedule or when something changes. You control the timing and the format, but you need write access and have to respect the PSA's limits.
• Pull: a platform reads counts from your API and applies them. Your API stays simple and read-only, but the data is only as fresh as the polling.
• Both (two-way): counts flow in both directions. It is the most flexible, and the most likely to create conflicts.

Which Should You Choose?

Start with the question of who owns which field. In most billing integrations, your product is the source of truth for quantity, and the MSP's agreement is the source of truth for price, cost, and terms.

That points to a safe default: one-way sync for quantity, with your product as the source, and no changes to price or cost fields unless the MSP asks for it. Then consider:

1. How often counts change. A product with daily changes needs a different cadence than one that changes monthly.
2. When it matters. Counts matter most at the MSP's billing date, so freshness there is more important than freshness at midnight.
3. PSA limits. Frequent writes across many partners can hit rate limits, so batching helps.
4. Auditability. The MSP should be able to see what changed, when, and why.

How Do You Avoid Billing Surprises?

Most billing surprises come from changes the MSP did not expect:

• Use effective dates, so a mid-cycle change lands on the right invoice.
• Show a preview or "dry run" before the first write to a new agreement.
• Require approval for large changes, such as a count that moves by a big percentage in one sync.
• Keep a change log the MSP can read, with the old value, the new value, and the reason.
• Tell the MSP when a sync fails, instead of silently leaving the old number in place.

A quantity that is slightly late is rarely a problem. A quantity that is wrong and unexplained always is. MSPCentric builds PSA integrations that sync counts with clear ownership, effective dates, and a change history MSPs can trust.

FAQ

Should a vendor write directly to the PSA?

It can, if it respects rate limits, writes only the fields it owns, and gives the MSP visibility and control. If you cannot guarantee that, a read-only API that a billing platform pulls from is the safer design.

How often should quantities sync?

Often enough that the count is right at the MSP's billing date, and no more often than your changes and the PSA's limits justify. Daily is common, and event-driven updates work well when counts change rarely.

What about changes in the middle of a billing period?

Handle them with effective dates, and decide with the MSP whether to prorate. The integration should record the date of the change, not just the new number.

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