If your practice runs on Sodium Practice Management, you can connect it to Tax Optimiser and pull your client list across in one click — no re-keying company names or Companies House numbers. You create an API key in Sodium, paste it into your firm settings, pick which Sodium practice (tenant) to read, and sync. Every limited-company client comes in as an organisation, matched on its Companies House number, ready for accounts and Corporation Tax. This guide walks the whole connection end to end.
Step 1 — Create an API key in Sodium
An API key is what lets Tax Optimiser read your client list from Sodium on your behalf — treat it like a password, because it gives the same level of access to your Sodium account. In Sodium, click your account avatar in the top-right corner and choose API Keys.
On the API Keys page, click Add API Key.
Give the key a name that tells you what it is for — for example Tax Optimiser — then click Create API Key. The name is just a label for your own reference.
Step 2 — Copy your API key
Your new key appears in the list. Use the reveal (eye) icon if you want to see it, then click the copy icon to copy it to your clipboard. Keep it safe and paste it straight into Tax Optimiser in the next step — anyone with this key can read your Sodium data, so don't email it around or write it down.
Step 3 — Enter the key in Tax Optimiser
In Tax Optimiser, open Firm Settings → Firm and choose the Integrations tab. Paste your key into the Sodium API Key box and click Save. The key is stored encrypted and shown masked — use the eye icon beside it if you ever need to check what is saved.
Step 4 — Choose your Sodium tenant
A tenant is your practice (workspace) in Sodium. Once your key is saved, click Load Tenants and Tax Optimiser will fetch the practices your key can see. Pick yours from the Sodium Tenant dropdown and click Save again so the choice is remembered.
Step 5 — Sync your clients
With a tenant selected, click Sync Clients from Sodium. Tax Optimiser reads your Sodium clients and brings them in as organisations. A few things worth knowing:
- Only limited companies (private and public) are imported by this button. Your Self Assessment clients have their own button — see Step 6. Partnerships, LLPs, trusts and charities stay in Sodium.
- Each client is created by its Companies House number, so its registered name, address and key dates are filled in from Companies House automatically.
- Each new organisation is tagged with its Sodium reference, so running the sync again won't create duplicates of clients you have already imported — it only brings across anything new.
When the sync finishes you'll land on your Organisations list, where the imported companies are ready to work on.
Step 6 — Sync your Self Assessment clients
Click Sync Individuals from Sodium. You'll find it on the same Integrations tab and also at the top of your Clients list. It brings in your Sodium Individual and Sole Trader clients as individuals, ready for their SA100s. For each client, Tax Optimiser reads the client's main contact in Sodium and takes their name, email, phone, UTR, National Insurance number and address.
- No duplicates. If someone is already one of your clients, they're matched first on their Sodium reference, then on their UTR, then on their email address. They are linked rather than created again.
- Your details win. For someone who is already a client, only empty fields are filled in from Sodium. A UTR, NI number, name or address you have entered in Tax Optimiser is never overwritten. The address is filled in only if every address line is empty.
- Clients without a usable email. Every individual needs a unique login email. If Sodium has no email for someone, or their email already belongs to another Tax Optimiser account, they're created with a placeholder email that is never sent anything. You can add their real email later from their client page. If the email belongs to the same person's existing account, use Send Invite instead.
- Nothing is sent. No login details are emailed to synced clients.
When the sync finishes you'll land on your Clients list with a count of the individuals created, updated, unchanged and skipped. Anyone who needs a look, such as a placeholder email or a Sodium client with no contact, is listed at the top. That's it — your Sodium client base is now in Tax Optimiser.
