A practical guide to Xero integration: syncing invoices, contacts, and payments, using the Xero API and webhooks, and deciding whether to connect an app or build custom.
Xero integration means connecting Xero, the cloud accounting platform, to the other software your business runs on so that information moves between them without a person retyping it. That might be your online store pushing sales into Xero as invoices, your point of sale sending daily takings across, or a custom app you built keeping customer records and payments lined up with your books. Done well, a Xero integration removes a whole category of manual work and the errors that come with it.
This guide is written for business owners, operations leads, and finance managers who are tired of copying numbers between systems, or who have a tool that does not talk to Xero and want to fix that. We will walk through what a Xero integration actually involves, the common jobs it does, how the Xero API works at a high level, and how to decide between connecting an off-the-shelf app and building something custom. There are no prices here, because the only honest number is a quote for your specific setup, and asking for one is free.
At its simplest, a Xero integration is a connection that lets another system read from or write to your Xero account. The word covers a wide range of setups. On one end there are ready-made connectors from the Xero App Store that link popular tools with a few clicks. On the other end there is custom middleware, software written specifically for your business, that maps your data to Xero and keeps the two sides consistent as things change.
Most integrations move one or more of a handful of record types. Contacts, which in Xero represent your customers and suppliers. Invoices and bills, which record what you are owed and what you owe. Payments, which mark those invoices as settled. Bank transactions, which feed reconciliation. Items, tracking categories, and tax rates, which give each line the right classification. A good integration knows which of these your business cares about and touches only those, in the right order, so Xero stays a clean record you can trust.
The reason this matters is that accounting is unforgiving about detail. A sales figure that lands in the wrong tax bucket, a duplicated invoice, or a payment that never got recorded all create work for someone at month end. A careful integration is worth far more than a quick one, because the whole point is to make the numbers right without a human checking them. If you are weighing whether an integration is worth the effort, a short conversation with us is free and will usually make the answer clear.
Businesses come to us with Xero integration needs that look different on the surface but share the same root problem: the same information lives in two places and someone is keeping them in step by hand. Here are the patterns we see most often.
An online store, whether on Shopify, WooCommerce, a marketplace, or a custom platform, generates orders all day. Pushing each sale into Xero as an invoice or a daily summary, with the right tax treatment and payment recorded, means your books reflect trading without anyone exporting spreadsheets. This is one of the most requested Xero integrations because the volume of orders makes manual entry impossible past a certain point.
Retail and hospitality businesses often want their point of sale to send a daily sales summary to Xero, split by payment method and tax rate, so the day's trading reconciles against the bank feed. A custom integration can shape that summary exactly the way your accountant wants to see it.
If you have built or commissioned a custom application, a booking system, a field service tool, a subscription platform, then that app knows when a customer owes money. Rather than rekeying invoices, the app can create them in Xero directly and mark them paid when the money arrives. Customers stay in one place, the books stay in another, and the two agree.
If your situation is on this list, or close to it, we can usually scope a build after one call. That call is free and there is no obligation to go further.
Xero exposes its data through a set of web APIs. The main one for accounting work is the Accounting API, which is where contacts, invoices, payments, and bank transactions live. There are also separate APIs for payroll, files, projects, and assets, each with its own rules. When someone says they are building a Xero integration, they usually mean writing software that talks to these APIs on your behalf.
Access is controlled through OAuth, an industry standard way of granting an application permission to act in your Xero account without handing over your password. A business owner connects the integration once, approves the specific permissions it needs, and from then on the software holds a token it refreshes automatically. This means you can revoke access at any time, and the integration only ever has the scopes you agreed to. Getting the OAuth flow right, including refreshing tokens before they expire and handling the case where a user disconnects, is one of the parts that separates a reliable integration from one that quietly stops working.
The API speaks in structured records. To create an invoice, the software sends a request describing the contact, the line items, the amounts, the tax rates, and a reference. Xero validates it against your organisation's settings and returns the created record, including the identifier you use to track it. Because Xero enforces its own rules, a good integration reflects those rules rather than fighting them, which is why the mapping work up front matters so much.
The hardest part of most Xero integrations is not sending one invoice. It is keeping two systems agreeing over months of activity, when records get edited, voided, and created on both sides. This is where careful design pays for itself.
For every record type, someone has to decide which system is the source of truth. Are customers mastered in your CRM and copied to Xero, or the other way round? Can an invoice be edited in both places, or only one? Answering this clearly up front prevents the most common failure, where a change on one side gets overwritten by an out of date copy from the other.
To avoid duplicates, the integration needs a dependable way to recognise that a customer in your app and a contact in Xero are the same person. That usually means storing the Xero identifier against your own record the first time they are linked, rather than matching on name or email every time, which is fragile. The same idea applies to invoices and payments, each of which carries an identifier you can hold on to.
There are two ways an integration learns that something changed. It can ask Xero on a schedule, which is called polling, or it can be told by Xero when specific events happen, which is what webhooks provide. Xero webhooks can notify your integration when contacts or invoices change, so the software reacts promptly instead of waiting for the next poll. Many integrations use both: webhooks for speed on the events that matter, and a scheduled sweep as a safety net so nothing is missed if a notification is ever lost.
Xero limits how many requests an integration can make in a given period, both per minute and per day. This is normal for any serious API and it means the software has to be polite. A well built integration spaces out its requests, batches work where it can, and slows down gracefully when Xero signals that it is being asked for too much, rather than failing or hammering the API. For a business with high order volume, respecting these limits while still keeping data current is a real part of the design.
Idempotency is the unglamorous idea that quietly saves you from a mess. If the network drops halfway through creating an invoice, the software has to be able to retry without risking a duplicate. That means designing every write so that running it twice has the same effect as running it once. Combined with clear error handling, retries for temporary failures, and alerts for the ones a human needs to see, this is what keeps an integration trustworthy on the days when something upstream misbehaves.
The difference between an integration you can ignore and one you have to babysit is almost entirely in how it handles the bad days, not the good ones.
Not every Xero integration needs custom software. The honest advice, which we give freely, is to use an existing connector when one genuinely fits your needs, and to build custom when it does not. Here is how we think about the choice.
The Xero App Store lists connectors for many common tools. If you use a mainstream platform, your data maps cleanly to Xero's model, and you are happy to work the way the connector expects, a ready-made app is often the sensible choice. It is quicker to switch on and someone else maintains it. There is no pride in building what you can buy.
A middle path exists too. Sometimes the answer is a thin piece of custom middleware that sits between an existing connector and Xero, handling only the parts the connector cannot. If you are not sure which category you fall into, that is exactly the kind of question a free consultation answers quickly.
FourCents is a custom software studio in Toronto, and we build Xero integrations the way we build everything else, by understanding the actual work first and writing code second. Here is roughly how a project runs.
We start by learning how your business records money today and where the pain is. Then we map every field that needs to move, from your system to Xero and back, including the awkward ones like tax treatment, currencies, and how you group sales. This mapping is the contract for the build, and getting it agreed with you and, where helpful, your accountant, prevents surprises later.
Xero provides a demo organisation and developer tools that let us build and test against realistic data without touching your live books. We use these to prove out the OAuth connection, the record creation, the sync logic, and the error handling before anything runs against your real account. You get to see it working on safe data first.
When you are happy, we connect the live account, usually starting with a limited slice of data so any surprises are small and easy to correct. Once it is stable, we open it up fully. From there the integration runs with monitoring, so if Xero has an outage, a token needs attention, or a record fails to sync, we know before you do. We also leave you with a clear record of what the integration does, so it is never a mystery box.
A focused Xero integration is often a matter of a few weeks rather than months, though it depends entirely on how many record types are involved and how particular your rules are. The fastest way to find out is to tell us your setup. A quote is free and there is no obligation attached to it.
It would be dishonest to pretend integrations are risk free. Being clear about the risks up front is how we keep them from becoming problems.
None of these are reasons to avoid an integration. They are reasons to build it with someone who has done it before and plans for the hard cases. We are happy to talk through the specific risks in your situation at no cost.
If double entry into Xero is eating your team's time, or you have a system that simply does not talk to your accounting, the next step is a short conversation. Tell us what systems you run, which records need to move, and what your month end looks like today. From that we can tell you honestly whether an off-the-shelf connector will do, whether custom middleware is the better fit, and roughly what a build would involve.
Asking is free, quick, and carries no obligation. Even if the answer is that you do not need us, you will come away with a clearer picture of your options. Reach out for a free consultation and we will map the fastest sensible path to a Xero setup you can trust.
A Xero integration is a connection between Xero and another system, such as your online store, point of sale, CRM, or a custom app, that moves information between them automatically. It means sales, invoices, contacts, and payments appear in Xero without anyone retyping them, which saves time and cuts errors.
If you use a mainstream tool and your data maps cleanly to Xero, an off-the-shelf connector from the Xero App Store is often the right and quicker choice. A custom integration makes sense when your source system is a custom or older tool, your data needs shaping in a specific way, or you need business rules that generic connectors cannot express. We are happy to tell you which fits, for free.
Through OAuth, an industry standard that lets an application act in your Xero account without ever seeing your password. You approve the specific permissions once, the integration holds a token it refreshes automatically, and you can revoke access at any time. The integration only ever has the access you granted.
Yes. A well designed integration can push records to Xero, pull records from Xero, or both. When syncing both ways, the important step is deciding which system is the source of truth for each record type so changes never overwrite each other. We work that out with you during discovery.
A focused integration covering one or two record types is often a matter of a few weeks. More involved builds with two way syncing, several record types, and particular business rules take longer. The honest answer depends on your setup, and we can give you a timeline after a short call.
Not if it is built properly. We store Xero's own identifiers against your records so the integration always knows when something already exists, and we design every write to be safe to retry. Combined with periodic reconciliation checks, this keeps duplicates and drift out of your books.
Xero updates its API over time, so an integration needs an owner who keeps it current. We build with monitoring so we know quickly if something fails, retries handle temporary outages automatically, and anything that needs a human raises an alert. This is why we treat an integration as something maintained, not built and forgotten.
Tell us what systems you run, which records need to move, and what your month end looks like today. From that we can scope the work and give you a quote. Asking is free, quick, and there is no obligation to proceed.