A relieving letter is the easiest document to forge — and the one HR trusts most
Onboarding teams use it to confirm the candidate left the previous employer cleanly. The candidate knows it. So when an exit was messy or a notice period was skipped, a quick edit in Word can rewrite history. Visual review passes. Structural analysis does not.
htpbe? analyzes the structural layer of the PDF file — the layer that records every edit, even invisible ones. We don’t inspect holograms, phone photos, or ID biometrics. If your fraud problem is a digitally fabricated or tampered relieving letter, we’re the most specific tool for it.
When htpbe? returns INCONCLUSIVE on a relieving letter, that’s the expected baseline (these documents legitimately come from desktop tools at many employers); combine with other markers before flagging.
One REST call, one deterministic verdict
Upload the PDF. The API returns INTACT, MODIFIED, or INCONCLUSIVE with named markers — in about three seconds.
How fake and tampered relieving letters actually look
Three real fraud mechanics we catch at the structural PDF layer.
Reason for separation rewritten
Candidate was terminated for cause but writes the letter as a voluntary resignation. Original document opened in Adobe Acrobat or an online editor; one paragraph replaced; re-export. Incremental update markers in the xref chain expose the edit.
Last working day backdated to skip the notice-period gap
There is a six-month gap between the real last working day and the next employer’s start date — the candidate was either out of work or working somewhere they can’t mention. The date on the relieving letter gets pushed forward. The visual page still looks signed and stamped; the modification timestamp tells a different story.
Letter authored from scratch when no real one exists
No relieving letter was issued — the candidate left badly or the previous employer refuses to issue one. The candidate writes one in Word, lifts the company logo from LinkedIn, signs HR Manager’s name, exports. Producer field shows Microsoft Word; image-stream metadata exposes the lifted logo.
The scale
Why your existing checks miss this
BGV calls the employer. The employer does not always answer.
When BGV cannot complete, the candidate fills the gap with a letter. Read the file.
BGV platforms (AuthBridge, IDfy, OnGrid, Springworks) call the previous employer to confirm separation. Indian BGV employer-response rates routinely run 70–85% — meaning 15–30% of cases get filled with the candidate’s submitted documents alone. htpbe? catches the file the candidate sent, regardless of whether the previous employer responds. Use both: BGV when reachable, htpbe? always.
Five forensic layers, one deterministic verdict
Every PDF we receive passes through the same structural pipeline — no model training, no thresholds to tune.
Metadata analysis
Creation and modification timestamps, producer and creator fields, XMP metadata — the first layer exposes basic tampering.
File structure
Xref tables, trailer chain, incremental updates. Any edit after export leaves a structural fingerprint here.
Digital signatures
Signature chain integrity and post-signature modifications produce deterministic markers. Certainty-level signal.
Content integrity
Fonts, objects, embedded content, page assembly. Multi-session edits and inserted objects are visible at this layer.
Verdict with markers
Deterministic output: INTACT / MODIFIED / INCONCLUSIVE, with named markers for every finding — suitable for audit trail.
Relieving letter and adjacent separation PDFs we check
Every type listed below is analyzed at the structural file layer — not the rendered image.
Detection capabilities
Deterministic structural signals. No probabilistic scores, no model training.
Producer signature on the letter
Authentic relieving letters come from the previous employer’s HRMS, payroll, or document-management system — recognisable producer signatures. When the producer is Microsoft Word, LibreOffice, Google Docs, or Chrome Headless, the letter was authored on a desktop.
Incremental update trail
Date edits, paragraph replacements, and signature swaps all leave incremental updates in the PDF’s xref chain. Authentic single-session exports have one xref; tampered files have two or more.
Letterhead and logo image consistency
Real corporate letterheads ship as part of the document template. Lifted-and-pasted logos appear as redundant image streams with mismatched compression — a structural fingerprint of fabrication.
Digital signature presence and chain validity
Many large employers digitally sign relieving letters. Authentic letters carry a valid signature chain; tampered letters either lack signatures or have invalidated chains.
Modification date vs. claimed last working day
The PDF’s ModDate is the moment the document was last touched. When ModDate is months after the claimed last working day, the file was edited after issuance — a high-confidence flag for backdated separations.
Font subset divergence across pages
Multi-session edits or page reassembly leave font subset prefix shifts. Single-session legitimate exports have consistent subsets across all pages.
Two HTTP calls to verify any relieving letter
Buyers can skip this section — developers, the integration is two HTTP calls.
Step 1 — submit the PDF
curl -X POST https://api.htpbe.tech/v1/analyze \
-H "Authorization: Bearer $HTPBE_API_KEY" \
-H "Content-Type: application/json" \
-d '{"url": "https://your-storage/candidate-relieving-letter.pdf"}'Step 2 — read the verdict
{
"id": "r1l2m3n4-5o6p-7q8r-9s0t-u1v2w3x4y5z6",
"status": "modified",
"modification_confidence": "high",
"modification_markers": [
"Adobe Acrobat producer with incremental update",
"Modification date 5 months after creation date",
"Two xref tables — content was edited after original export"
],
"producer": "Adobe Acrobat 24.0",
"creator": "Workday HRMS",
"creation_date": 1693526400,
"modification_date": 1706659200,
"has_digital_signature": false,
"xref_count": 2,
"has_incremental_updates": true
}The original was exported from Workday HRMS (a real corporate workflow). Then five months later it was opened in Adobe Acrobat and re-saved — adding a second xref table. The verdict is modified at high confidence. The candidate took a real letter and edited it after the fact.
Customer Stories
Teams that stopped document fraud
Compliance, finance, and risk teams use htpbe? to catch manipulated PDFs before they become costly mistakes.
Caught an invoice where the total had been changed by less than a thousand dollars. Without this I would have approved it without a second look.
Sarah M.
AP Manager
United States
We had three applicants in the same week with bank statements that looked completely fine. Two of them were flagged as modified. You simply cannot see this by reading the document — it is in the file structure.
Lars V.
Risk Analyst, Online Lending
Netherlands
Salary slips were coming with altered figures. We identified two problematic files before the placement was finalised.
Priya K.
HR Operations Lead
India
Since we started checking documents this way, we stopped two applications early in the process that would have been very difficult to reverse later.
Julien R.
Fraud Analyst, Fintech
France
Some applicants were sending PDFs that looked authentic but had been edited in ways not visible to the eye. We now ask for verified originals when something is flagged. Already saved us from a few bad decisions.
Marta S.
Compliance Coordinator
Spain
One invoice was caught because there was a mismatch between the document dates and structure. That particular case would have cost us significantly.
Tariq A.
Finance Manager
United Arab Emirates
Frequently asked questions
modified with the incremental-update flag and modification timestamp gap.inconclusive, prompting manual employer verification rather than an automatic reject.Related solutions and guides
HR & Hiring
Pre-employment document fraud detection for talent ops and BGV operators.
Fake Experience Letter Detection
Sister page — structural forensics for previous-employment letters.
Fake Salary Slip Detection
Salary slips submitted alongside relieving letters as employment proof.
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