LFM2.5-Encoder-350M-PII-Detector — LiteRT

LiquidAI/LFM2.5-Encoder-350M-PII-Detector converted to LiteRT (.tflite) for on-device inference. Detects ~40 kinds of personal information across 16 languages, fully offline — a natural fit for on-device redaction where the text must never leave the phone (demo Space).

File	Recipe	Size
LFM2.5-Encoder-350M-PII-Detector_wi8fc.tflite	int8 dynamic-range (linears + embedding, convs float)	364 MB	mobile + desktop (iPhone-verified bit-exact, 52 ms)
LFM2.5-Encoder-350M-PII-Detector_fp16.tflite	fp16 weights, float compute	712 MB	desktop — full fidelity; phone memory limits (XNNPACK per-signature fp32 unpacking)

Signatures

pii_128 / pii_512 (S = 128 / 512, batch 1, right-padded): input_ids int32 [1, S], attention_mask int32 [1, S] → BIOES logits float32 [1, S, 161], zeroed at padded positions. Argmax per token, then decode BIOES spans; the label id ↔ entity mapping ships in label_schema.json.

import numpy as np
from ai_edge_litert.interpreter import Interpreter
from tokenizers import Tokenizer

tok = Tokenizer.from_file("tokenizer.json")
it = Interpreter(model_path="LFM2.5-Encoder-350M-PII-Detector_wi8fc.tflite")
run = it.get_signature_runner("pii_128")
ids = tok.encode("My email is jane@example.com.").ids
x = np.zeros((1, 128), np.int32); m = np.zeros((1, 128), np.int32)
x[0, :len(ids)] = ids; m[0, :len(ids)] = 1
lg = list(run(input_ids=x, attention_mask=m).values())[0]
labels = lg[0, :len(ids)].argmax(-1)   # 0 = O; see label_schema.json

Verification

Task-level parity vs the PyTorch reference (name + email + phone sentence): fp32 and fp16 reproduce the reference entity tags exactly. int8 keeps all multi-token spans (email, phone) intact and dropped exactly one tag in our test — an entity-end token whose fp32 decision margin was only 0.53 logits (a genuinely borderline call). If you need maximum recall on borderline tokens, use the fp16 file on desktop; on phones the int8 file is the artifact.

On an iPhone 17 Pro the int8 file reproduces the desktop outputs bit-exactly (cosine 1.000000, max diff 0.0) at 52 ms per pii_128 pass (6 threads, XNNPACK).

License

LFM Open License v1.0 (see LICENSE, unchanged from the base model). Note the license's commercial-use threshold (Section 5). This repository redistributes converted Derivative Works of LiquidAI/LFM2.5-Encoder-350M-PII-Detector with modification notices per Section 4; all credit for the model to Liquid AI.