MODLOG vs Custodian — Which Car App Is Right for Your Build?

If you've been searching for a car app to track your build, you've probably come across two names: Custodian and MODLOG. Both are UK-based. Both let you log your vehicle history. But they're built for completely different people.

Here's the honest breakdown — no fluff.

What Custodian Is Built For

Custodian launched in 2020 and has built something genuinely impressive for a specific audience: classic car owners, collectors, and people who want a digital paper trail for insurance purposes.

Their flagship features are:

• Digital history files — upload documents, MOT certificates, invoices
• Specialist insurance — their real revenue model, partnered with classic car insurers
• The Showroom — a dealer marketplace for classic and prestige cars (think £120k Porsche 911s and 1924 Aston Martins)
• Car handover — transfer your car's full digital history to a new owner on sale

It's well-designed, free to use, and has 70,000+ members. If you own a classic or a prestige car and want a clean, professional record of its history — Custodian is excellent.

But here's the thing: it's not built for builders.

What MODLOG Is Built For

MODLOG is for the other side of the car world. The MR2 on coilovers. The 986 Boxster with a custom exhaust and 18-inch AXE wheels. The Golf GTI with a Stage 2 map and a cold air intake. The modified daily that started as a stock car and became something else entirely.

MODLOG is modification-first. Every feature is designed around one core question: what have you done to your car, what did it cost, and who did it?

• Log every mod — category, cost, supplier, date fitted, photos, before/after
• Spend analytics — see where your money's gone by category over time
• Public build pages — share your build with the community, earn likes and badges
• Build leaderboard — ranked by total investment. Show the world what you've built.
• "Where to Buy" links (Pro) — see a part on someone's build? Click to buy it.
• PDF build report (Pro) — prove your modifications when you sell the car. Every part, every receipt, every photo. Documented.
• Receipt scanning — photograph your invoice and AI extracts the mod data automatically
• VRM lookup — enter your reg and your vehicle is populated instantly via the DVLA database
• Trade profiles — workshops and tuners get a business page with proximity-based lead generation

The Honest Side-by-Side

| Feature | Custodian | MODLOG | |---|---|---| | Target user | Classic/prestige car owner | Modified car builder | | Modification tracking | Basic logging | Full category breakdown with costs, suppliers, photos | | Community & social | No - Private only | Yes - Leaderboard, public builds, follows, likes | | Parts marketplace | Dealer-only showroom | Yes - Buy parts directly from real builds | | Spend analytics | No | Yes - Category charts, trend tracking | | Receipt scanning | No | Yes - AI Vision feature | | Insurance integration | Yes - Their main USP | — | | Car handover/provenance | Yes - Excellent | Yes - Full build history PDF on sale | | VRM instant lookup | No | Yes - DVLA API integrated | | Trade/garage profiles | No | Yes - Trade tier with lead gen | | Free tier | Yes - Unlimited | Yes - 1 vehicle free forever | | Pricing | Free (monetised via insurance) | Free / £3.99 Pro / £19.99 Trade |

Which One Should You Use?

Use Custodian if:

• You own a classic, historic, or high-value car
• Your main need is documentation, insurance, and provenance
• You're not a heavy modifier — you want a clean paper trail

Use MODLOG if:

• You modify your car — even a little
• You want to track what you've spent and what you've done
• You want a public build profile the community can see
• You're buying or selling modified parts
• You're a garage, workshop, or tuner wanting to reach local customers

The Bottom Line

Custodian is a digital filing cabinet for people who own expensive cars.

MODLOG is for people who build them.

Different products. Different communities. Different purposes. If you're reading this, you already know which one you are.

[Start your free build log → modlog.online]