THE RETURNS · TDS AND TCS

TDS returns, from the books to the token number.

Quarterly returns under both Acts, corrections, the Q4 salary annexure and Form 16 — on the same read of the books as everything else.

See it on one of your clients How it was built and tested →

Forms

138, 140, 143 and 144 under the Income-tax Act, 2025, and 24Q, 26Q, 27Q and 27EQ for earlier years and corrections

From the books

Deductions and challans read from the client's books; one payment split over two challans stays exact to the paisa

Payment codes

Chosen from the section and the deductee; where the books cannot tell, it asks you once and remembers

Checks

Every validation in Protean's file format, in plain words, with the row it points to

Interest and fee

Late deduction, late deposit and the late-filing fee, worked out before you file

The file

Written in Protean's layout, read back and re-written byte for byte before it is saved

Corrections

C1, C2, C3, C4, C5 and C9 in one correction file, from what you change

Q4 salary

Annexure II with the tax worked out in both regimes, and Form 16 Part B

Certificates

Form 16 Part A from TRACES joined to Part B by PAN; Form 16A and 27D emailed to each deductee

Around it

A returns calendar, a challan master, a deductee master and a reminder to the client for data

TESTED BEFORE IT WAS SHOWN TO A CLIENT

Each rule is checked against a second engine, built separately.

Corrections read back as TRACES would

A separate checker reads each correction file the way the central system does and rebuilds the corrected return from it. In one run, 1,230 random corrections and 506 corrections of corrections rebuilt exactly.

Bugs planted to test the tests

Twenty-six realistic mistakes were planted in the correction code, one at a time. The tests caught every one.

Salary tax worked by hand

Rebate under section 87A with marginal relief, surcharge with marginal relief and cess, in both regimes, checked against cases worked on paper.

WHAT IT DOES NOT DO YET

Files are being run through Protean's File Validation Utility before the first live filing. Reading the CSI and Consolidated files from TRACES waits for real sample files, because their formats are not guessed. Form 138 for the fourth quarter waits for Protean to publish its layout. Corelytix does not sign certificates; that remains yours.