# Diesel Decoder vs NAPA Filters

The clearest difference is rating: NAPA Filters at 5.0 against Diesel Decoder's 3.3. NAPA Filters also leads on in-app purchases (none vs 1) and update cadence (monthly vs every 3 months). Diesel Decoder's advantage is ratings volume (30 vs 2) and chart position (#200 vs unranked). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Diesel Decoder sells 1 in-app purchase, starting at $29.99 per month. NAPA Filters asks for nothing beyond the download.

NAPA Filters holds the better App Store score, 5.0 against 3.3. That said, the two scores are not equally well evidenced: Diesel Decoder has 30 ratings behind it against 2, so its average is the more settled of the two.

Diesel Decoder ships an update every 3 months, NAPA Filters monthly. The most recent releases landed on October 9, 2026 and October 15, 2026 respectively.

## The numbers

| Metric | Diesel Decoder | NAPA Filters |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.3 (30 ratings)](https://appshunter.io/ios/app/diesel-decoder/id1529808675/reviews) | **[5.0 (2 ratings)](https://appshunter.io/ios/app/napa-filters/id6477851966/reviews)** |
| Number of ratings | **30** | 2 |
| Positive reviews | 27.3% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 3 months | **Monthly** |
| Monetization | Free with in-app purchases | **Free** |
| Best chart rank | **#200** | — |
| Size | 43 MB | 67 MB |
| Requires iOS | 15.6 | **15.1** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Diesel Laptops LLC](https://appshunter.io/developer/1345401052) | [Premium Guard Inc.](https://appshunter.io/developer/1556625190) |

## What reviewers say

### Diesel Decoder

[App page](https://appshunter.io/ios/app/diesel-decoder/id1529808675)

**Currently charting:** #200 Top Grossing · Reference (US App Store)

This tool connects via Bluetooth to heavy commercial vehicles to read and clear diagnostic trouble codes. It displays live data, allows bi-directional commands, and generates shareable reports through a cloud platform. Requires dedicated hardware for operation.

**Highlights:** Read/clear Diagnostic Trouble Codes (DTCs), View live data parameters, Run bi-directional commands, Generate local and cloud reports, Share reports via Diesel Health Platform, Requires Diesel Decoder hardware

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Decoder Professional Monthly | $29.99 | per month |


### NAPA Filters

[App page](https://appshunter.io/ios/app/napa-filters/id6477851966)

Easily find the right filters for your vehicle using a "Search By Vehicle" tool or a dynamic search option. You can also look up NAPA part numbers or interchange OE and competitor part numbers.

**Highlights:** Search by vehicle year, make, model, and engine, Dynamic search by typing vehicle description, Search by NAPA part number, Interchange OE or competitor part numbers, View product information

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Diesel Decoder free?

Diesel Decoder is free to download, with in-app purchases available.

### Is NAPA Filters free?

NAPA Filters is free to download, with no in-app purchases.

### Which has better reviews, Diesel Decoder or NAPA Filters?

NAPA Filters is rated higher. Diesel Decoder averages 3.3 out of 5 from 30 ratings, while NAPA Filters averages 5.0 from 2 ratings.

### Do Diesel Decoder or NAPA Filters have ads?

Neither Diesel Decoder nor NAPA Filters shows ads.

### Which is updated more often, Diesel Decoder or NAPA Filters?

Diesel Decoder ships an update every 3 months, and NAPA Filters monthly. Most recently, Diesel Decoder was updated on October 9, 2026 and NAPA Filters on October 15, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*