You need a Xero developer when no existing app connects your other software to Xero the way your business actually works. Check the Xero App Store first, because an off-the-shelf connector is usually cheaper and quicker. A custom Xero API integration is a small piece of software that reads and writes your Xero data, such as contacts, invoices, bills and payments, so your team stops re-keying it. Building one involves Xero's connection rules, its API limits, decisions about who owns and hosts the code, and a plan for keeping it running when Xero changes things. This guide covers each of those so you can brief a developer properly, or decide you don't need one.
Check the Xero App Store first
Before you talk to any developer, search the Xero App Store for your other system's name. Many job management, inventory, CRM and ecommerce products already have a connector. Some are built by the vendor and some by third parties.
An existing app is usually the right answer when:
- It syncs the records you care about in the direction you need
- It handles your setup, such as multiple organisations or tracking categories
- Your process can bend slightly to fit the app, rather than the other way round
A custom integration starts to make sense when the app doesn't exist, only half does the job, or forces a workaround your team will resent. For example, if your job system raises invoices but the connector can't post them against the right tracking category, your bookkeeper ends up fixing every invoice by hand. Another case is when you're connecting something no vendor will build for, such as an in-house database or an industry-specific system.
If you're unsure, ask the vendor of your other system directly. They often know which connectors their customers use and where those connectors fall short.
What a custom Xero API integration actually touches
A Xero integration is really a set of decisions about data. The usual records involved are:
- Contacts. Customers and suppliers need to match between systems, or you get duplicates. Someone has to decide which system owns a contact's details and what happens when they're edited in both.
- Invoices and bills. These are the core of most integrations. Line items, account codes, tax rates and due dates all have to map correctly.
- Payments. Some businesses want payments recorded in Xero to flow back to the other system so staff can see what's been paid. Others record payments elsewhere and push them into Xero.
- Tracking categories. Xero allows two active tracking categories, often used for jobs, regions or departments. If your reporting depends on them, the integration has to set them every time.
- Items and accounts. Item codes and the chart of accounts need consistent mapping, and someone has to decide what happens when a new code appears.
Multi-org setups add another layer. Each Xero organisation is a separate file with its own contacts, accounts and limits. If you run several entities, the integration needs to know which organisation each transaction belongs to, and intercompany transactions need careful thought.
A good developer will spend more time on these mapping questions than on code. That's normal and it's where most integration problems are prevented.
How Xero connections, app approval and rate limits work
You don't need the technical detail, but these points affect cost and design.
Connecting. Integrations connect using OAuth 2.0. Someone with access to your Xero organisation approves the connection, and no passwords are shared. Access tokens expire after 30 minutes and are refreshed automatically. If the integration stops refreshing for long enough, though, someone has to reconnect it.
Custom connections. For an integration that only ever talks to your own Xero organisation, Xero offers a paid option called a custom connection. It's designed for machine-to-machine links like this and avoids some of the reconnection hassle.
App approval. Apps built for wider use have to go through Xero's app partner review before they can connect to more than a small number of organisations. A private integration for your business usually doesn't need this.
Developer pricing. Xero has introduced tiered developer pricing based on how many organisations an app connects to and how much data it uses. Ask your developer which tier applies to your integration and include it in your running costs.
Rate limits. Xero caps how often an integration can call the API, currently 60 calls a minute and 5,000 calls a day per organisation. Most businesses never get near that. High-volume operations can, though, such as large ecommerce stores or anyone syncing thousands of transactions daily. The integration should batch its requests and handle "slow down" responses gracefully.
Who owns and hosts the integration
This question gets skipped surprisingly often. Before any work starts, agree on:
- Code ownership. Do you own the source code, or are you licensing the developer's product? Either can be fine, but you should know which.
- Hosting. The integration has to run somewhere, whether that's a cloud service, your own environment or the developer's. Find out who pays for it and who can access it.
- Credentials. Who holds the Xero app credentials, and what happens to them if you change developers?
- Logs and alerts. When a sync fails, who gets told, and where can you see what went wrong?
If the developer disappears, you want to be able to hand the integration to someone else without starting again.
What to ask a Xero developer before you engage them
A short list of questions will tell you a lot:
- Have you built Xero integrations before, and what did they connect?
- Which records will move, in which direction, and how often?
- How will you stop duplicate contacts and invoices?
- What happens when a sync fails? Will it retry, alert someone, or quietly stop?
- Will we own the code, and where will it be hosted?
- How do you test it before it touches our live Xero file? Xero provides a demo company for this.
- What ongoing costs should we expect, including Xero's developer fees and hosting?
- Who looks after it when Xero changes its API?
Vague answers to questions 3, 4 and 8 are a warning sign.
Keeping it running when Xero changes its API
Xero updates its API over time. It adds features, retires old endpoints and changes authentication or pricing rules. Xero gives notice, but someone has to read those notices and act on them. Integrations rarely break on their own. They break because nobody was watching.
Agree on a maintenance arrangement up front. This might be a support agreement, a set number of hours a year, or a clear understanding that you'll call the developer when Xero announces a change. Also keep simple documentation describing what the integration does, so whoever maintains it isn't guessing.
How MYOB integrations compare
MYOB has its own API with similar concepts: contacts, sales, purchases and payments. The details differ. Authentication and developer key arrangements are different, and MYOB has also changed its API over time, which has caught out integrations that weren't maintained. Its marketplace of ready-made connectors is smaller than Xero's for some industries, so custom work comes up more often. If you're on MYOB, see our MYOB API integration service.
What it costs
Costs vary widely depending on the size of the business, how many systems are involved and how much needs to be custom-built, so we scope every project first and give you a fixed quote after a free initial chat. If you'd like your processes and systems mapped in detail before deciding anything, our $5,000 Process & Systems Audit produces a written report you can act on with us or anyone else.
Frequently asked questions
Do I need a Xero developer or a Xero consultant?
A Xero consultant or bookkeeper sets up and tidies your Xero file. A developer builds software that connects Xero to other systems. Many integration projects need both perspectives, because the mapping decisions are accounting decisions.
Can a custom integration damage my Xero data?
It can create messy data if it's poorly designed, for example by creating duplicate contacts or posting to the wrong accounts. Testing against Xero's demo company first and limiting what the integration is allowed to change reduces that risk considerably.
How long does a Xero integration take to build?
It depends on how many records are involved and how clean the data is in both systems. A one-way invoice sync is a much smaller job than a two-way, multi-organisation integration. A developer should be able to give you a timeline once the scope is clear.
Will I need to keep paying after it's built?
Usually yes, in small ways. Expect hosting, any Xero developer fees that apply, and maintenance when Xero changes its API. Ask for these to be spelled out before you start.
If you're weighing up an App Store connector against a custom build, you can read more about our Xero API integration service. Or book a free initial chat and we'll talk through what you're trying to connect and whether you need custom work at all.