---
id: pydlt
version: "0.3.5"
license: MIT
license_treatment: permissive
maintenance: aging
---

# pydlt — A pyre-python library to handle AUTOSAR DLT.

License: permissive · Maintenance: aging · Downloads: 129.1K/mo

## What it is and what it does

PyDLT is a Python library for reading and writing AUTOSAR DLT (Diagnostic Log and Trace) protocol messages, following the AUTOSAR Specification V1.2.0 R4.0. It provides APIs to construct both verbose messages (with typed arguments like strings) and non-verbose messages (raw binary payloads), serialize them to DLT files with storage headers, and parse DLT files back into message objects for inspection and analysis.

The library has no external runtime dependencies and installs as a pure Python wheel, making it lightweight for automotive diagnostic tooling. However, it does not yet support all DLT type formats—notably TYPE_LENGTH_128BIT, TYPE_ARRAY, VARIABLE_INFO, FIXED_POINT, TRACE_INFO, and TYPE_STRUCT are documented as unsupported, which may limit its applicability to certain diagnostic data streams.

Use it for:

- Write diagnostic log messages from an embedded system or test harness into a DLT file for later analysis.
- Parse and inspect existing DLT log files from automotive ECUs to extract diagnostic events and trace data.
- Build automotive diagnostic tooling that needs to generate or consume AUTOSAR-compliant DLT protocol messages.
- Integrate DLT logging into Python-based vehicle simulation or testing frameworks.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

PyDLT reads and writes AUTOSAR DLT (Diagnostic Log and Trace) protocol messages to and from files, implementing the AUTOSAR DLT V1.2.0 R4.0 specification.

Yes, if you work with AUTOSAR DLT protocol and your message types fall within the supported format subset. The permissive MIT license, zero runtime dependencies, and straightforward API make it a practical choice for automotive diagnostic workflows. Be aware that maintenance is aging (last commit 525 days ago) and several DLT type formats remain unsupported; verify that your use case does not rely on the documented limitations before committing to production use.

## Install

pip install pydlt
uv add pydlt
poetry add pydlt

## Installing pydlt

Before you install: Low install friction with no runtime dependencies. Maintenance status is aging—last commit was 2025-03-07 and the project has not seen active development for several months, though the repository remains active and not archived.

License in practice: MIT license is permissive; you may use, modify, and distribute this package freely with minimal restrictions, provided you include the license notice.

Quickstart:

from pydlt import DltFileWriter, DltMessage, ArgumentString, MessageType, MessageLogInfo, StorageHeader

msg = DltMessage.create_verbose_message(
    [ArgumentString("hello")],
    MessageType.DLT_TYPE_LOG,
    MessageLogInfo.DLT_LOG_INFO,
    "App", "Ctx",
    message_counter=0,
    str_header=StorageHeader(0, 0, "Ecu")
)
with DltFileWriter("output.dlt") as writer:
    writer.write_messages([msg])

Verify before relying:

- Whether the aging maintenance status and 525 days since last release affect stability or compatibility with current AUTOSAR specifications.
- Whether the documented limitations (TYPE_LENGTH_128BIT, TYPE_ARRAY, VARIABLE_INFO, FIXED_POINT, TRACE_INFO, TYPE_STRUCT) impact your specific DLT message types.

## Package facts

- License: MIT (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: aging
- Downloads: 129.1K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

AUTOSAR DLT protocol, diagnostic log and trace, DLT file reader writer, automotive logging, DLT message parsing, automotive, diagnostics, protocol-parser

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