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Subcontractors

How do I manage subcontractor purchase orders across several countries and currencies in field service?

Raise one purchase order per subcontractor visit, in the subcontractor's own currency, with the PO number sent to them with the job, and check it against your approval limits after converting it to your base currency. When the subcontractor's invoice comes in, match it to that PO in the same currency, send it to your accounting system as a draft bill dated on the invoice, and let the accounting system apply the exchange rate and record any gain or loss when you pay. VAT follows where the work happens, not where the subcontractor is based, so work on fixed plant at a site abroad is usually taxed in that country.

  • One PO per visit (or a contract PO drawn down per visit), in the sub's currency, with the PO number on the job.
  • Approval limits are set in your base currency; convert the PO at the rate on the PO date to check them.
  • The PO's base-currency value is an estimate. The bill's rate sets your costs; the payment's rate sets the FX gain or loss.
  • Invoice and PO must be in the same currency to match; ApprovalMax requires the same currency and supplier.
  • Work on equipment fixed to a building is land-related for VAT: taxed where the site is.
Fieldproxy

This page covers the field and purchasing side. It is not tax advice: for VAT registration abroad and cross-border payroll, ask an adviser in each country before the first job there.

Facts checked as of November 2026. Sources at the end of the page.

Step by step

How it works, step by step

The records are the same in every country. What changes per country is the currency, the language, the tax treatment and the documents a subcontractor must hold.

1. Set up each subcontractor once

Store the country, the currency they invoice in, their VAT or tax number, their language, the trades they cover, and their compliance documents with expiry dates. In Xero you can give a contact a default foreign currency, so their bills and purchase orders open in it.

2. Raise a PO for the visit

The PO carries the PO number, subcontractor, site, job, scope, a not-to-exceed amount, the currency and the PO date. A contract that covers many sites (one subcontractor looking after 30 stores, say) can be one blanket PO that each visit draws down, as long as every visit records which PO and how much.

3. Approve against limits in your base currency

Approval limits only work in one currency. Convert the PO amount at the rate on the PO date (for example, a manager approves up to 1,000 GBP, a director above). The converted figure is for the approval check and budget; the PO itself stays in the subcontractor's currency.

4. Send the PO with the job, in their language

The subcontractor gets the job, the PO number and the scope in their own portal or app, in their language, and quotes the PO number on their invoice. Pricing you charge your customer stays hidden from them.

5. Capture proof of work at the site

Photos, checklists, readings and a signature on the job, so the invoice can be checked against what was done. For refrigeration work this includes refrigerant handled and the engineer's F gas certificate number for that country.

6. Match the invoice to the PO

Match on PO number, supplier and currency, then compare amounts and lines. Set a tolerance (for example, up to 5% or 50 EUR over the PO goes through, above that needs approval). ApprovalMax's bill-to-PO matching for Xero only offers approved POs with the same currency and supplier as the bill.

7. Post a draft bill and let accounting handle FX

Send the bill to Xero as a draft in the invoice currency, dated on the invoice date, so your approval tool still applies. Xero shows the exchange rate for the day a foreign currency transaction is created, lets you override it on a single transaction, and recommends reviewing unrealized currency gains and losses before period-end close.

Where it breaks

Why it goes wrong

These are the problems buyers raised on our sales calls: a UK refrigeration and mechanical engineering firm with in-house and external engineers in several countries, and a UK lift supplier whose service is delivered by subcontractors across North America and Europe.

Three tools, one approval chain

The lift supplier described purchasing that runs from the stock system into Xero and then into ApprovalMax before anything is issued, with job management spread across email and Xero projects. Each hop is a place where the PO number, the currency or the job link gets lost.

Exchange rates that disagree

Unleashed fills a PO's exchange rate from its own buy rate, lets you edit it until the PO is Receipted, and says its rates do not sync with your accounting software. Xero uses its own rate for the day. So the same PO can show two base-currency values, and the gap looks like a variance when it is only a rate difference.

Paperwork nobody can read

Subcontractors abroad send back handwritten job sheets, photographed, in their own language. The office cannot check the work against the invoice, so invoices get paid on trust.

Compliance that differs by country

The refrigeration firm has a strict compliance policy for subcontractors. A UK F gas certificate, company or individual, is not valid for work in the EU; engineers need an EU-recognised qualification for work there. One expiry date per subcontractor is not enough when the right certificate depends on the country of the site.

One PO, many sites

When one contractor covers about 30 sites, a PO per site is too many and one PO for all of them hides which visit used how much. A blanket PO with draw-downs per visit fixes both.

Invoices that skip approval

Both buyers wanted invoices to land in Xero as drafts so the approval workflow still runs. A field tool that posts bills as approved goes around the controls finance relies on.

The options

Ways to do it

ApproachHow subcontractor POs workWeak spotGood for
Email, spreadsheets and XeroPOs raised in Xero and emailed; jobs tracked in a spreadsheet. Multiple currencies are on Xero's Comprehensive and Ultimate plans in the UK, not Ignite or GrowNo link between the PO, the visit and the proof of work; the sub's paperwork arrives by emailA handful of subcontracted visits a month
Xero with ApprovalMax (plus Unleashed for stock)ApprovalMax runs multi-level approvals on Xero POs and bills, and has supported POs in any Xero currency since December 2016; bills match to POs in the same currency and supplierStrong on finance controls but knows nothing about the job, the site or the engineer; Unleashed and Xero hold different ratesFinance-led teams that already run approvals here
Enterprise FSM with a PO module (Dynamics 365 Field Service)A PO links to a work order, moves from Submitted to Approved, takes receipts, and a PO bill records the vendor invoice numberA large implementation; PO approval is a status change, so limits by amount need extra setupOrganisations already on Microsoft Dynamics
Configurable FSM with a subcontractor portal (Fieldproxy)PO per visit or blanket PO on the job, approval gates by amount, subcontractor portal in their language, compliance documents with expiry, invoices synced to Xero with its multi-currency supportYour PO fields, limits and matching rules are agreed with you before go-liveMulti-country engineering and service firms with in-house and external engineers

As of November 2026, from each vendor's own documentation (sources below). Check the current version before relying on any one feature.

Worked example

A worked example: one subcontracted visit in Germany

Say a UK refrigeration firm (base currency GBP) sends a German subcontractor to repair a cold room at a client's store near Hamburg. All rates and amounts are made up to show the flow.

StepRecordNumbers
PO raisedPO-2041 to the German sub, in EUR, NTE for the repair1,800 EUR
Approval checkConverted at the PO-date rate (say 1 EUR = 0.85 GBP); manager limit 1,000 GBP1,530 GBP, so it goes to a director
Job sentJob, PO number and scope in German in the sub's portal; F gas certificate checked as valid for the EUAccepted the same day
Invoice receivedQuotes PO-2041; one extra valve not on the PO1,950 EUR, 150 EUR over
VarianceOver the 5% tolerance, so the extra line goes to the job owner with the sub's photo of the old valveApproved
Draft bill in XeroIn EUR, dated on the invoice; Xero's rate that day (say 0.86)1,677 GBP cost on the job
PaidPaid a month later at, say, 0.871,696.50 GBP paid; 19.50 GBP realised FX loss, booked by Xero, not on the job

The job's cost is the bill, not the PO estimate and not the payment. Keeping the FX loss in accounting keeps job margins comparable across countries.

Before you buy

What to check before you buy

Good signs

  • Currency is a field on the PO and the bill, not only on the customer invoice
  • Approval limits by amount, with the base-currency conversion shown
  • Blanket POs with draw-downs per visit
  • The PO number goes to the subcontractor with the job and comes back on their invoice
  • Subcontractors see their jobs in their own language, and never your customer pricing
  • Compliance documents per subcontractor and per country, with expiry dates that block work
  • Bills reach Xero as drafts in the invoice currency, so ApprovalMax still runs

Red flags

  • All POs forced into your base currency
  • The tool converts at its own rate and posts base-currency bills to Xero
  • Bills posted as approved, skipping your approval step
  • A paid seat for every subcontractor
  • One certificate expiry field for everything
  • Photos and job sheets that stay in email, away from the PO

In Fieldproxy

Setting it up in Fieldproxy

Fieldproxy is described in one line: Best for processes that don't fit a template, set up for you. So the records, fields and rules below are configured with you; names marked e.g. are examples.

Subcontractors on the same system

Subcontractors sign in to a portal that shows only their jobs (/solutions/subcontractor-management). They accept work, update the status and add photos, forms and notes. Fieldproxy is one price per company with unlimited users, so adding subcontractors does not add seats. See /pricing.

Compliance with expiry dates

Each subcontractor's insurance and licences are kept on file with expiry dates, and the ones about to lapse are flagged before you offer work. Add the per-country documents your policy needs (e.g. EU F gas certificate, insurance per country, signed NDA). The Watcher agent (/agents/watcher-agent) flags jobs offered to a sub whose document for that country has lapsed.

POs on the job, with approval gates

A PO record linked to the job and the subcontractor (e.g. po_number, currency, amount, base_amount, po_date, blanket_po). Approval workflows (/solutions/approval-workflows) pause the PO above your limit (e.g. over 1,000 GBP) until the right role approves, and log who approved and when.

In each person's language

Each person picks their own language on web and mobile, from 27 (/solutions/multi-language). A subcontractor in Spain reads the job in Spanish while the record stays the same for your office. The Vision agent (/agents/vision-agent) reads a photographed job sheet into the job's fields.

Invoice to PO, then Xero

The Document intelligence agent (/agents/document-intelligence-agent) turns an incoming PDF into line items, so the subcontractor's invoice can be compared with the PO; anything over tolerance goes for approval. Customer invoices sync to Xero (/integrations/xero), including Xero's multi-currency invoicing. Sending subcontractor bills to Xero as drafts in the invoice currency is set up with you.

UK and EU

VAT, CIS and posted workers across borders

In the UK, amounts on a VAT invoice must be expressed in sterling for VAT purposes. VAT Notice 700 section 7.6 allows the UK market selling rate at the time of supply, HMRC's published period rate, or another rate HMRC agrees in writing, and the rate in effect at the time of each supply applies.

Where the work happens matters more than who does it. HMRC's VAT Notice 741A says services relating to land are supplied where the land is, and lists maintenance and repair of a building and the installation of machines that become a fixture of the property; equipment permanently installed in a building counts as land. Repairing a machine that is not part of the building is not land-related. When a UK VAT-registered business buys land-related services in the UK from a supplier that belongs outside the UK, it accounts for the VAT under the reverse charge. For B2B services in general, the place of supply is where the customer belongs.

Within the EU, B2B services sold to a business in another EU country are usually reverse charged by the customer, with exceptions. Who accounts for VAT on work at a site in each country depends on that country's rules, so check before the first job there.

For UK subcontractors, the Construction Industry Scheme covers installation, not repair. HMRC's manual says a complete air-conditioning installation is in the scheme while replacing parts is outside it, and repairs to building service systems are outside unless the contract includes making good to the building. Lifts are an integral part of the building, so installing one is a construction operation, but maintenance and repair of that machinery is outside the scheme. Flag each job as installation or maintenance.

For your own UK engineers sent abroad, an employee sent temporarily to work in an EU country for up to 2 years can stay in the UK National Insurance scheme, proven by a certificate of coverage (a PDA1) from HMRC. Keep it on the engineer's record next to their F gas certificate for that country.

How switching works

How switching to Fieldproxy works

We move your data over and set the system up to the way you already work. Fieldproxy replaces the old tool; it does not run alongside it.

  1. Show us one visit end to end

    A real subcontracted job abroad: the PO, the approval, the sub's paperwork, the invoice and what landed in Xero and ApprovalMax.

  2. We set up subcontractors, POs and limits

    Subcontractor records with country, currency, language and documents; PO fields and blanket POs; approval limits in your base currency.

  3. We connect Xero as drafts

    Bills go to Xero as drafts in the invoice currency, so ApprovalMax and your accountant's FX handling stay as they are.

  4. Go live with one country first

    Start with the subcontractors in one country, check a month of POs against invoices, then add the rest.
Subcontractor managementApproval workflowsXero integrationPricing: one price per company, unlimited users

FAQ

Questions people ask

Should the PO be in my currency or the subcontractor's?
The subcontractor's. That is the amount they agreed to and will invoice. Show the base-currency value beside it for approval limits and budgets, and treat it as an estimate.
Which exchange rate date should I use?
For approvals, the PO date. For your books, the bill's date, which is what Xero uses by default for a new foreign currency transaction. The payment date's rate then decides the realised gain or loss.
Can one purchase order cover many sites?
Yes, as a blanket PO that each visit draws down. Record the PO and the amount used on every visit so you can see what is left and which site used it.
Can subcontractor invoices go to Xero as drafts so ApprovalMax still applies?
They should. Posting drafts in the invoice currency keeps your approval workflow and lets Xero apply its exchange rate. Check that the field tool does not convert the bill to your base currency first.
Does Xero handle multiple currencies on every plan?
No. In the UK, multiple currencies are on the Comprehensive and Ultimate plans, not Ignite or Grow. In the US, Xero lists multi-currency on its Established plan.
Is a UK F gas certificate valid for work in the EU?
No. The UK government says a UK F gas certificate, company or individual, is not valid for work in the EU, and you need a recognised qualification from an EU member state.
Can subcontractors use the app in their own language?
In Fieldproxy, each person picks their own language from 27, on web and mobile, and the job record stays the same for the office. Ask any vendor to show the subcontractor's screen, not only the office one.

Sources

Competitor details on this page come from the vendors' own pages and documentation, checked as of November 2026. Plans and prices change, so check the vendor's current page before you decide.

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