Copomex and PostalKit, compared
Both read the same national catalog, so the data is not what separates them. What separates them is how you pay for it: Copomex sells credits that never expire, PostalKit sells a monthly quota. Which of those is cheaper depends entirely on how often you call it.
What Copomex is
A Mexican postal code API that has been running for years and is the best known of them. It sells prepaid query packages rather than a subscription: you buy a block, it does not expire, and you use it until it runs out. Its own pricing page states that published prices are before the 16% IVA.
It publishes at this address:
copomex.com
Side by side
| Item | PostalKit | Copomex |
|---|---|---|
| How you pay | A monthly subscription | Prepaid credits that do not expire |
| Free tier | 100 requests a month, no card | 50 queries, first project only |
| 5,000 requests | $149 MXN a month | $399.30 MXN plus IVA |
| 50,000 requests | $499 MXN a month | $1,331.00 MXN plus IVA |
With the 16% IVA added, the Copomex package covering 5,000 queries comes to $463.19 MXN and the one covering 50,000 comes to $1,543.96 MXN. Those are one-off purchases; the PostalKit figures are per month.
Prices verified on August 17, 2026.
Where Copomex is the better buy
There are two cases where it plainly is, and no amount of arithmetic in the table above changes them.
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Occasional volume.
Credits that do not expire are the right shape for a one-off import or a few thousand lookups a year — their smallest package is 1,000 queries for $133.10 MXN plus IVA, bought once. A subscription bills every month whether you call it or not, so if your usage arrives in bursts months apart, buying a block costs less than keeping a plan open.
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A published availability figure.
Copomex advertises 99.9% availability. PostalKit publishes no uptime number anywhere, deliberately, because it has no service agreement to stand behind one. If a figure you can point at in a procurement review is what you need, that is a real difference and it is not in our favour.
The other side
Where PostalKit is the better buy
Steady monthly volume is the case the table settles: at 5,000 queries a month, a subscription at $149 MXN costs roughly a third of buying the equivalent package at $463.19 MXN with tax, every month, forever.
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More than one question.
PostalKit publishes 21 endpoints across eight resource groups — postal codes, settlements, states, municipalities, localities, streets, geocoding and account — so a postal code, a colonia search and a walk down the address hierarchy are all first-class calls rather than one lookup you post-process.
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Identifiers that stay put.
The catalog is stored as related tables, and the ids you store today still resolve after the next refresh. That is what makes it safe to keep a colonia id on a customer record.
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You can tell what you are reading.
The source is re-checked on the first of every month and nothing moves unless it actually changed, and one call to GET /v1/account/db-version tells you which version you are on. Freshness you can query beats freshness you are promised.
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A spec, not just docs.
An OpenAPI document and a Postman collection are published and regenerated on every deploy, so a client can be generated rather than written. Every response carries its own rate-limit headers.
We would rather you checked that list against their documentation than took our word for it, which is why this page compares prices — which we verified — and not feature counts we did not.
Which one to pick
If your usage is occasional and a postal code lookup is all you need, buy a block of credits and stop reading. If you call it every month, or you need more of the address hierarchy than a single lookup returns, the subscription is cheaper and the API is wider. The free tier is 100 requests a month and asks for no card, so this is testable rather than arguable.
The same comparison against the other two: DIPOMEX, Postalia. If you have not picked a provider at all yet, the SEPOMEX catalog guide covers the free official file first.