Telematics Interoperability: Standards, APIs & Open Data

Jul 2, 2026 Resolute Dynamics

Telematics platform interoperability is the ability of platforms and vehicles from different manufacturers to exchange data through common standards and open APIs, so a fleet operator gets one unified view of a mixed fleet instead of a separate portal for every brand.

For a fleet running trucks from three manufacturers, excavators from two more, and aftermarket trackers on the rest, interoperability is what turns a dozen incompatible data feeds into a single, comparable dataset.

This guide explains the walled-garden problem interoperability solves, the vehicle-bus protocols beneath every platform, the industry standards that impose a common format, the API layer that delivers them, the EU regulation now forcing the market open, and how a platform is built to stay vendor-neutral.

This article states the position as of mid-2026. Standards version and regulations phase in over time, so version numbers and effective dates carry a source or a date so the page ages honestly.

What Is Telematics Platform Interoperability?

Telematics platform interoperability means that data generated by one vendor’s vehicles or devices can be read, understood, and combined by another vendor’s software without custom, one-off engineering for each pairing. It rests on shared data formats and open interfaces: when two systems agree on what a field is called, what type it holds, and how it is delivered, they interoperate.

Without that agreement, every new vehicle brand or device model added to a fleet is a fresh integration project, and the fleet’s data stays fragmented across systems that cannot talk to each other.

The Walled-Garden Problem in Fleet Telematics

The walled-garden problem is the practice of locking a fleet’s vehicle data inside a proprietary OEM portal in a format only that manufacturer’s software can read. A fleet operator who buys vehicles from several manufacturers ends up with several separate portals, several logins, and several incompatible data formats, with no single place to compare utilization, fuel, or fault codes across the whole fleet.

For a mixed fleet numbering in the hundreds, that fragmentation makes a cohesive operational view effectively impossible and ties the operator to each manufacturer’s telematics contract. Interoperability standards and open-data regulation are the two forces breaking this pattern apart.

Interoperability vs. Integration vs. Open Data

Interoperability, integration, and open data describe three related but distinct ideas, and the difference matters when specifying a platform. Integration is the act of connecting two specific systems, often with custom code for that pair. Interoperability is the property that lets systems connect without that custom work, because they follow shared standards.

Open data is the principle — increasingly a legal right — that the party who generates data can access it and direct it to a recipient of their choice. Integration solves one connection; interoperability makes connections repeatable; open data decides who controls the flow.

The Vehicle Data Layer — Protocols Beneath the Platform

Interoperability begins at the vehicle’s data bus, because that is where telemetry originates and where the first layer of standardization either exists or does not. Before a platform can normalize data, the vehicle has to expose it in a form that can be read, and the protocols that govern that exposure differ between heavy-duty and light vehicles.

SAE J1939 for Heavy-Duty Vehicles

SAE J1939 is the standardized, CAN-based communication protocol used across heavy-duty and off-highway vehicles, and it is the reason truck data is comparable across brands. J1939 encodes vehicle parameters using Suspect Parameter Numbers (SPNs) grouped into Parameter Group Numbers (PGNs), so a value such as engine speed or fuel rate carries the same identifier regardless of manufacturer.

This standardized naming is what lets a fleet collect comparable metrics across a mixed set of trucks and interpret fault information consistently. The protocol operates within CAN’s constraints — 8-byte frames on a bus commonly running at 250 or 500 kbit/s — using a transport protocol to segment larger messages.

OBD-II and Light-Vehicle Diagnostics

On-Board Diagnostics II (OBD-II) provides a standardized diagnostic interface for light vehicles, exposing emissions and basic engine data through a common connector and parameter set. It gives aftermarket devices a consistent way to read core diagnostics from passenger vehicles and light commercial vans, though it exposes a narrower and more emissions-focused dataset than J1939.

Heavy vehicles increasingly support OBD variants such as WWH-OBD (World Wide Harmonized OBD) and OBD-on-UDS alongside J1939, which a platform may read as a supplement or a fallback when full J1939 access is unavailable.

Why Raw Bus Data Alone Is Not Interoperable

Raw bus data is standardized in structure but not automatically usable, because decoding it into human-readable values requires a database of conversion rules. To turn raw J1939 frames into physical values, a platform needs a conversion database — typically a DBC file — that maps SPNs and PGNs to their meaning, and while the official SAE J1939 Digital Annex covers a large share of parameters, most vehicles also carry proprietary parameters that still conform to J1939 but require reverse engineering to interpret.

Direct connection to a vehicle’s internal CAN bus is also discouraged by truck manufacturers and can affect warranty, which is precisely why higher-level interface standards exist.

Telematics Interoperability Standards

Two industry standards create the common data formats that make fleet telematics interoperable across manufacturers: the FMS Standard with its rFMS API for commercial road vehicles, and ISO 15143-3 (AEMP) for construction and off-road equipment. Each was created to solve the walled-garden problem in its sector, and each defines not just data fields but how those fields are delivered.

The FMS Standard and rFMS API for Trucks and Buses

The Fleet Management System (FMS) Standard is a manufacturer-independent interface to commercial-vehicle data, developed in 2002 by the six European truck makers Mercedes-Benz, MAN, Scania, Volvo (including Renault), DAF, and Iveco under the umbrella of ACEA.

It lets third-party fleet software read a standardized set of vehicle data through a gateway rather than by connecting directly to the internal CAN bus, with the data coded according to SAE J1939 and broadcast at repetition rates ranging from 20 milliseconds for fast-changing values such as engine speed to 10 seconds for static values such as the vehicle identification number.

The remote FMS (rFMS) API extends this to the cloud, letting a platform access FMS data from an OEM’s back office over the internet using existing vehicle hardware. rFMS is an HTTPS-based REST API that returns JSON and is defined by an OpenAPI 3.0 specification, and its current version is 5.0.0, published on 25 July 2025, which adds a push method so an OEM can actively send data on subscription alongside the original pull method where the client requests data on demand.

Access is token-authenticated and the response version is negotiated through the HTTP Accept header, so a client requests the specific rFMS version it supports.

ISO 15143-3 (AEMP) for Construction and Off-Road Fleets

ISO 15143-3, widely known as the AEMP telematics standard, defines a common data format for sharing telematics data across mixed construction and off-road equipment fleets. The Association of Equipment Management Professionals introduced the first version in 2010 to bring order to fragmented OEM telematics, refined it as AEMP 2.0 in 2012, and it was adopted as the international standard ISO 15143-3 in 2016.

It specifies a common JSON and XML payload for core parameters — equipment identity, location, operating hours, fuel, and machine status — using the same field names and types across manufacturer portals, so a fleet running Caterpillar, John Deere, Volvo, and other machines can pull all of them into one application through endpoints that speak the same schema.

What These Standards Standardize — and What They Leave Proprietary

These standards standardize a common core of operational parameters and their delivery format, but they deliberately leave room for manufacturer-specific data outside the shared set. The FMS and ISO 15143-3 specifications define which parameters are mandatory, which are optional, and how often they are delivered, which is what makes cross-brand aggregation reliable.

Both also allow OEM-specific extensions — additional triggers, proprietary parameters, or richer data available only through the manufacturer’s own interface — so a standards-based feed gives a fleet a dependable common denominator, while the deepest vehicle-specific data may still sit behind the OEM’s proprietary API. Adoption also varies, so a platform validates what each OEM actually exposes rather than assuming full compliance.

The API Layer — How Platforms Exchange Fleet Data

Standards define the data; APIs deliver it, and modern telematics interoperability is built on web APIs rather than direct hardware connections. The rFMS and ISO 15143-3 standards are both delivered as web APIs, which means the mechanics of exchange — the request style, the update model, and the access controls — follow familiar web patterns that any platform can consume.

REST, JSON, and OpenAPI in Telematics APIs

Telematics interoperability standards are delivered as REST APIs returning JSON, described by machine-readable OpenAPI specifications. A REST API exposes fleet data as resources — vehicles, statuses, positions — that a client retrieves over HTTPS, and the JSON responses carry the standardized fields the specification defines.

An OpenAPI specification describes the endpoints and the response structure in a single file that can generate client and server code, which lowers the cost of integrating each new source. The principles that make these interfaces robust and consistent are examined in the guide to telematics API design best practices.

Pull vs. Push, Polling Cadence, and Rate Limits

Telematics APIs deliver data through either a pull model, where the client requests it, or a push model, where the server sends it on subscription. Pull-based polling is simple but wasteful if run too frequently, and OEMs commonly cache data and recommend polling no more often than the underlying update rate — many fleets run one-to-four-hour cadences for cost and scale efficiency, with the FMS standard specifying vehicle status at least once every 60 minutes.

Push, added in rFMS 5.0.0, avoids redundant polling by delivering data as it changes. APIs also enforce rate limits, returning an HTTP 429 response when a client exceeds its quota, so an interoperable platform is built to respect each source’s limits and back off gracefully.

Authentication and Access Control

Every telematics API gates access with credentials and tokens, so interoperability never means unrestricted access to a fleet’s data. An OEM issues a client with credentials — a client identifier and secret — that are exchanged for an access token carried in the authorization header of each request, and the token scopes the client to the specific vehicles the fleet has authorized.

Getting this layer right is a security requirement as much as an interoperability one, and the controls that protect fleet data end to end are detailed in the guide to securing fleet data with AI and telematics.

The Regulatory Push Toward Open Fleet Data

Regulation, not just industry standards, is now forcing telematics data open, and the EU Data Act is the milestone that changed the market. Where standards made cross-brand data exchange technically possible, the Data Act makes access to it a legal right, shifting control of vehicle-generated data from the manufacturer to the fleet that operates the vehicles.

The EU Data Act — Applicable Since 12 September 2025

The EU Data Act, Regulation (EU) 2023/2854, entered into force on 11 January 2024 and became applicable on 12 September 2025. It is a horizontal regulation covering data generated by all connected products — from industrial machinery to connected vehicles — and it gives the user of a connected product the right to access the data that product generates and to share it with a third party of their choosing.

The European Commission published tailored Guidance on Vehicle Data on 12 September 2025, clarifying how Chapter II of the Act applies to the automotive sector and confirming that operational data such as mileage, fuel or energy consumption, diagnostic codes, position, and driver-behaviour metrics falls within scope, while manufacturer trade secrets such as proprietary ECU calibration remain outside it.

What Fleet Operators Can Now Do

Since 12 September 2025, a fleet operator in the EU has the legal right to access the operational data its connected vehicles produce and to nominate a third-party provider to receive that data directly from the manufacturer.

In practice this means a fleet can obtain its vehicle data without installing aftermarket hardware such as an OBD dongle or a separate CAN integration, can choose a fleet-management platform other than the manufacturer’s own, and can switch providers without losing historical data through the Act’s portability provisions.

The question a fleet asks a manufacturer shifts from which product it must buy to see its own data, to how the manufacturer transmits the data the vehicles already produce.

The Staged Timeline and What Comes Next

The Data Act phases in over three stages, so its full effect on open fleet data continues to arrive through 2027. Core data-access and sharing provisions applied from 12 September 2025; enhanced interoperability requirements for cloud services take effect from 12 September 2026; and full data-portability standards take effect from 12 September 2027.

A parallel move toward standardized, accessible vehicle data appears in the new-generation smart tachograph, whose standardized interface extends the same openness principle to more commercial vehicles. The direction is consistent: structured, accessible, portable data as the default rather than a proprietary exception.

Building an Interoperable Telematics Platform

An interoperable telematics platform is built on four principles: normalize everything to one data model, ingest through standards, keep the platform’s own interfaces open, and stay vendor-neutral across the fleet. The goal is a platform that adds a new vehicle brand or device without a new integration project and gives the operator a single, portable view of the whole fleet.

Normalize Everything to a Common Data Model

The foundation of interoperability is normalizing every incoming feed — rFMS, ISO 15143-3, raw J1939, OBD — into one internal data model with consistent field names and units. A platform that maps each source to a common schema on ingestion lets everything downstream treat a fault code or a fuel reading identically regardless of which brand or protocol it came from.

This normalization is what converts many incompatible feeds into the single comparable dataset that makes mixed-fleet analytics possible.

Standards-Based Ingestion for Mixed Fleets

A platform ingests mixed-fleet data most reliably by consuming the industry standards first and treating proprietary feeds as extensions. Reading rFMS for trucks and buses and ISO 15143-3 for construction equipment covers the standardized core across manufacturers, while direct J1939 or OEM-specific APIs fill in what the standards leave out.

The architecture for handling this diversity of sources and hardware is examined in the guide to vehicle data capture architecture for heterogeneous fleets, and the backbone that moves the normalized data through the platform in real time is described in the analysis of real-time streaming architectures for fleet telemetry.

Avoiding a New Walled Garden — Open APIs, Portability, and Sovereignty

A platform that solves the walled-garden problem must not recreate it, so it exposes its own data through open APIs and supports portability. Offering a documented API, standard export formats, and the ability to move historical data out is what keeps a fleet’s data the fleet’s own, in line with both the Data Act’s portability principle and good practice.

Where that data physically lives and which jurisdictions govern it is a related decision examined in the guide to fleet data sovereignty and cross-border vehicle data flows.

How Capture, Connect, and Control Stay Vendor-Neutral

A vendor-neutral platform captures, connects, and controls fleet data without tying the operator to a single source of vehicles or devices. Sensors and standards-based feeds capture data from any compliant vehicle; open, standardized APIs are how that data is connected across a mixed fleet; and a normalized data model lets control and safety systems act on any vehicle in the fleet the same way.

A fleet operator planning a mixed-brand deployment can talk to Resolute Dynamics about standards-based, vendor-neutral telematics.

Frequently Asked Questions

What is the rFMS standard?

The remote FMS (rFMS) standard is an HTTPS REST API that lets fleet software access standardized commercial-vehicle data from an OEM’s back office over the internet, returning JSON defined by an OpenAPI specification. It extends the FMS interface — developed in 2002 by six European truck makers under ACEA — to the cloud, and its current version is 5.0.0, published in July 2025.

What is ISO 15143-3 / AEMP?

ISO 15143-3, known as the AEMP telematics standard, defines a common JSON and XML data format for sharing telematics data across mixed construction and off-road equipment fleets. It was introduced by the Association of Equipment Management Professionals in 2010, refined as AEMP 2.0 in 2012, and adopted as an ISO standard in 2016, and it lets equipment from different manufacturers feed one application through a shared schema.

Does the EU Data Act let me access my fleet’s data?

Yes. Since the EU Data Act (Regulation (EU) 2023/2854) became applicable on 12 September 2025, a fleet operator in the EU has the legal right to access the operational data its connected vehicles generate and to nominate a third-party provider to receive that data directly from the manufacturer, without installing aftermarket hardware. Trade secrets such as proprietary ECU calibration remain out of scope.

Can one platform manage a mixed-brand fleet?

Yes, a platform that ingests industry standards and normalizes data to a common model can manage a mixed-brand fleet from one interface. Reading rFMS for trucks and buses, ISO 15143-3 for construction equipment, and J1939 or OEM APIs for the rest, then mapping every feed to one schema, gives a single comparable view across manufacturers.

Is J1939 data interoperable across manufacturers?

Largely yes, because SAE J1939 uses standardized parameter identifiers (SPNs within PGNs) so core values mean the same thing across brands, which is why a common set of data can be decoded across a mixed heavy-duty fleet. However, most vehicles also carry proprietary parameters that conform to J1939 but require the manufacturer’s conversion rules to interpret.