# Papertrail Auto vs DiagonalOBDII

The clearest difference is review sentiment: Papertrail Auto at 83% against DiagonalOBDII's 0%. Papertrail Auto also leads on ratings volume (24 vs 1) and update cadence (every 4 days vs every 2 weeks). DiagonalOBDII's advantage is rating (5.0 vs 4.8). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. Papertrail Auto sells 1 in-app purchase, starting at $15.99 per month and DiagonalOBDII sells 4 in-app purchases, starting at $12.99 per month. Whichever you choose, the download price is not the number that matters.

DiagonalOBDII holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: Papertrail Auto has 24 ratings behind it against 1, so its average is the more settled of the two. Written reviews complicate that: 83% of Papertrail Auto's written reviews are positive against 0% of DiagonalOBDII's, so the app with the better star average is not the one people write more warmly about.

Papertrail Auto ships an update every 4 days, DiagonalOBDII every 2 weeks. The most recent releases landed on October 9, 2026 and October 5, 2026 respectively.

## The numbers

| Metric | Papertrail Auto | DiagonalOBDII |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.8 (24 ratings)](https://appshunter.io/ios/app/papertrail-auto/id6444321445/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/diagonalobdii/id6743419784/reviews)** |
| Number of ratings | **24** | 1 |
| Positive reviews | **83.3% of reviews** | 0.0% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 4 days** | Every 2 weeks |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 149 MB | 21 MB |
| Requires iOS | **13.0** | 18.1 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Papertrail Technologies LLC](https://appshunter.io/developer/1653844050) | [Kyle Louderback](https://appshunter.io/developer/1400068218) |

## What reviewers say

### Papertrail Auto

[App page](https://appshunter.io/ios/app/papertrail-auto/id6444321445)

This app helps car owners meticulously document their vehicles, from basic specs to maintenance history and memorable journeys. It offers AI-powered input, secure cloud storage, and the ability to generate presentations or transfer ownership records.

**Highlights:** Detailed vehicle documentation, AI-powered data input, Photo and description uploads, Create car 'Stories', Generate PDF/web presentations, Transfer ownership records, Encrypted cloud storage

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Papertrail Pro | $15.99 | per month |


### DiagonalOBDII

[App page](https://appshunter.io/ios/app/diagonalobdii/id6743419784)

This app helps mechanics perform vehicle drive cycles more efficiently. It provides real-time monitoring of emissions monitors and diagnostic trouble codes (DTCs), offering clear guidance and instant explanations to ensure vehicles pass inspection quickly and accurately.

**Highlights:** Live drive cycle monitoring, Immediate diagnostic trouble code (DTC) identification, Real-time emissions monitor status, Precise drive cycle parameter guidance, Professional, easy-to-navigate dashboard, Instant code explanations

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Diagonal Premium Monthly | $12.99 | per month |
| Diagonal Premium Trial | $12.99 | per month |
| Shop Owner - Monthly | $17.99 | per month |
| Diagonal Premium Yearly | $99.99 | per year |


## Frequently asked questions

### Is Papertrail Auto free?

Papertrail Auto is free to download, with in-app purchases available.

### Is DiagonalOBDII free?

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

### Which has better reviews, Papertrail Auto or DiagonalOBDII?

DiagonalOBDII is rated higher. Papertrail Auto averages 4.8 out of 5 from 24 ratings, while DiagonalOBDII averages 5.0 from 1 ratings.

### Do Papertrail Auto or DiagonalOBDII have ads?

Neither Papertrail Auto nor DiagonalOBDII shows ads.

### Which is updated more often, Papertrail Auto or DiagonalOBDII?

Papertrail Auto ships an update every 4 days, and DiagonalOBDII every 2 weeks. Most recently, Papertrail Auto was updated on October 9, 2026 and DiagonalOBDII on October 5, 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.*