How Tally data sync works

Why sync is needed at all

TallyPrime is desktop software: the company data lives on the office PC or server. Phones and browsers cannot open it directly. Remote desktop gets around this by streaming the PC's screen; sync takes a different approach and moves the data itself, so it can be shown in phone-friendly screens to many people at once. See remote desktop vs sync app for the trade-offs.

Step 1: reading from Tally

The connector runs on the same Windows PC where TallyPrime is open. It asks Tally for the data of the companies that are open: masters such as ledgers, groups, stock items, units and cost centres, and transactions such as vouchers with their bill-wise and inventory details. Tally answers these requests itself, so the connector does not open or change Tally's data files directly. This is why Tally needs to be running with the company open for sync to work.

Step 2: keeping a synced copy

The connector sends what it reads to the online service, which keeps a copy of each company's data organised for fast reports: balances, outstanding, ageing, GST summaries, stock. Once set up, the copy keeps being refreshed, so new vouchers made in Tally appear in the app. The copy is only as fresh as the last sync, which depends on the Tally PC being on, Tally being open with the company, and the PC having internet.

Step 3: writing back into Tally

When a user creates a voucher or a master in the app, it is not saved in the online copy as the truth. It is sent to the connector, which passes it to Tally. Tally applies its own checks, just as if the entry were typed in Tally. If Tally accepts it, the voucher is saved in Tally and flows back into the synced copy. If Tally refuses it, for example because a ledger is missing or a value is invalid, the reason comes back to the user to fix. Tally stays the books of record.

A well-designed sync app keeps writing off until the business owner switches it on, so nothing changes in Tally unexpectedly.

Freshness and what to expect

The practical rule: keep the Tally PC on with the companies open during working hours.

Keeping sync healthy

• Keep the connector PC's Windows updated and set it not to sleep during working hours.
• Open the same companies in Tally every morning; a company left closed is not refreshed.
• If figures in the app look old, check first whether Tally is open and the PC is online.
• Keep masters tidy in Tally. Duplicate ledgers or items in Tally appear as duplicates in the app too.
• If you move Tally to a new PC, install the connector there and link it again.

Security points to check in any sync app

• How does the connector link to your account? (For example, by scanning a code shown on the PC.)
• Can you set roles, so salespeople see only their own customers?
• Is writing into Tally off by default, and who can switch it on?
• Is there an app lock and a record of who did what?
• Can you disconnect a company or the PC when needed?

Also remember that a synced copy is not a backup of your Tally data; keep your Tally backup routine. See backing up accounting data.

How Cashflow OS sync works

In Cashflow OS, the Windows connector runs on the Tally PC, reads the companies open in TallyPrime and keeps a synced copy for the mobile and web apps. You link it by signing in with your mobile number and scanning the QR the connector shows. Writing back is off until the owner switches it on per company; Tally validates each entry and a refused one returns with Tally's reason. Several companies can be synced into one account. Setup steps are in the connector setup guide.