Certificates, transcripts and notarial records become a side-by-side draft: numbers and dates locked to the original, seals and signatures described the way certified translators describe them, layout rebuilt row by row. Nothing is final until you approve it.
PDF / PNG / JPG · Chinese ⇄ English · artifacts deleted after 30 days
The same document, page by page. Structure, tables and seal positions line up, and not one digit moved. Every screenshot here is real output; the documents are synthetic fixtures — a real customer document never becomes marketing material.
Certified translation has one hard rule: stamps, embossed seals, seam seals and signatures are described in brackets and never pasted in as images — copying the red seal across is a leading reason documents get rejected. CertTwin reads the text inside the seal, translates it, writes a proper italic bracketed note, and makes you approve each one.
Before translation, code freezes every critical value into an immutable token the model cannot touch; afterwards code verifies each one and puts it back exactly. The model never gets a chance to re-type your passport number or your grades.
Click any text on the page and the matching place highlights on the source and the translation at once, so you never hunt for correspondences. Edits redraw immediately, seal descriptions need your explicit approval, and every action lands in an audit log.
Every draft runs all nine checks. If any one of them does not pass, the job stops for human review instead of going out — including the case where two models read the same scanned digit differently.
| Coverage | Every page extracted, native text layer fully reconciled | pass |
| Visual elements | Seal and signature descriptions await your approval | review |
| Number conservation | The set of digits matches between source and translation | pass |
| Block completeness | No semantic block dropped or blocked | pass |
| Language purity | No source-language residue or Chinese punctuation left behind | pass |
| Term consistency | A repeated source string translates identically everywhere | pass |
| Minimum font size | Nothing squeezed below the readable floor | pass |
| Layout collisions | Glyph-level scan; any overlapping text is held | pass |
| Side-by-side review | Human sign-off — never auto-approved | review |
A PDF, a scan or a phone photo. Files go straight to private storage, with no third-party middleman.
IDs, dates and amounts are frozen before translation and verified back afterwards. On scans, a second model re-reads the digits.
Check each place, edit in line, approve the seal descriptions, and export the review draft as a PREVIEW_ONLY PDF.
Tuned for the formatted paperwork behind study abroad, immigration, visas and notarization.
No. Every page is stamped PREVIEW_ONLY — a review draft meant for human verification and whatever certification step follows. It is not itself a certified translation and does not guarantee acceptance by any authority. Whether a translator's declaration gets attached is your call.
They are used only to produce your translation, processed by Google Cloud (Vertex AI) in the United States, and the artifacts are deleted after 30 days. This site sells nothing and never asks for passwords, card numbers or ID numbers.
Chinese ⇄ English today — the pair behind most study-abroad and immigration paperwork. More are on the roadmap.
The product is in closed testing, and we want every problem a real document exposes to actually get fixed. Email us with your document types and purpose to join.
Free during closed testing. Send us an email describing what you need translated and we will open an account.