Overview

Profiles can hold contact details and personal context, including birthdays, food preferences, allergies, social links, and how you met someone. A relationship graph, interaction timeline, life events, gifts, follow-ups, and journal sit alongside those profiles. That combination is useful when thoughtful outreach depends on remembering more than a person's address, but it makes Contact Book a poor match for teams seeking a synced address book or a CRM centered on email and calendar activity.

Users can export everything or delete an account through self-service settings. The operator says it does not sell user data, share it with advertisers, or run third-party analytics or session recording on logged-in pages. Application servers and the database are hosted in Germany on operator-managed servers. Public endpoints use TLS 1.3, disks are encrypted at rest, and backups are encrypted before leaving the primary host. Daily snapshots are retained for 30 days at a separate physical location, with restore tests performed quarterly.

Key features

Contact Book's HTTP API, CLI, and MCP access the same data and access rules. GraphQL, WebSockets, signed outgoing webhooks, and client libraries for multiple programming languages give developers several ways to connect it to surrounding systems. This is a meaningful advantage for builders who want to work with relationship data programmatically, though the integration surface does not compensate for the lack of email or calendar sync.

Follow-up reminders and interaction history support ongoing relationship management. Users may also be able to sign in through Google, LinkedIn, GitHub, or Microsoft rather than a password. The founders say they answer support emails themselves, and monitored contact addresses are usually answered within one working day. A refund of the most recent charge is available through account settings within the first 30 days of any new paid period.

Pricing

The Free plan costs 0.00 EUR per free, making it a low-risk option for an individual who wants to try a personal CRM without a subscription. Standard monthly costs 10.00 EUR per month (billed monthly); Standard annual costs 100.00 EUR per year (billed annually). The annual term is cheaper than paying the monthly rate for a full year, while monthly billing avoids committing to a year. Both paid plans are presented as Standard, with no separate feature differences stated.

The plans suit solo use rather than team purchasing: Contact Book is built for individual users, and no seat or contact caps are stated for these plans. Its free entry point and export option make it easier to start and leave, but users who expect automated contact updates should look elsewhere regardless of plan.

Platforms

Contact Book is available on the web and through an API. The mobile-app platform is web, rather than separate iOS or Android apps. For developers, CLI and MCP access add other interfaces to the same data and permissions; for users seeking native mobile apps, this platform mix is a limitation.

Who it's for

Contact Book is best for solo users keeping track of friends, family, professional networks, parents, freelancers, or volunteer relationships. Its detailed profiles and personal-history tools are most useful when remembering preferences, past interactions, and life events matters. It is less suitable for teams that need shared workflows or for anyone relying on email and calendar synchronization to maintain records automatically.

Pros and cons

Pro: Profiles combine practical contact details with personal context, interaction history, gifts, life events, and reminders, making the product more than a basic contact list.
Pro: API, CLI, MCP, GraphQL, WebSockets, signed webhooks, and language libraries offer builders multiple integration paths.
Pro: Self-service export and deletion, Germany-hosted infrastructure, encryption, and a defined backup routine give users useful data-control and operational safeguards.
Con: There is no email or calendar sync, so users must maintain contact records rather than relying on automatic updates from those tools.
Con: The listed platform mix is web and API, not native mobile apps, which may frustrate users who want a dedicated phone app.

Alternatives

Personal CRM Software is the broader category to consult when comparing options. Choose Contacts+ Personal CRM if native iOS and Android apps and daily sync matter; its free plan includes one account and 1,000 contacts. KeepContact is an iOS option with a free tier capped at 15 contacts and three reminders, or a monthly Pro plan at 4.99 USD per month for unlimited contacts and reminders. Meaningful is a web alternative whose free Alpha plan offers all features and unlimited contacts.

For Apple users, Revere is available on iOS and macOS, with a free plan covering unlimited people, notes, and reminders. SoonCall is an iOS option for tracking five meaningful relationships for free, with a paid monthly plan at 6.99 USD per month. Dextr offers an iOS and macOS free plan with unlimited contacts, AI organization, reminders, places, and events. Kithmap is a free-for-now open beta for macOS and web. Fabriq is an Android and iOS alternative; its monthly plan costs 4.99 USD per month and covers up to 150 people, categorized notes, personal reminders, and Connection Starters.

Verdict

Choose Contact Book if you are a solo user who wants detailed personal relationship records and developer access to the same data through several interfaces. Its main advantage is the combination of rich relationship context, export controls, and integration options. Look elsewhere if native mobile apps, team-focused workflows, or automatic email and calendar synchronization are essential.

	Contact Book	Nat
Free plan	Yes	No
Free trial	No	No
Paid from	€8.33/mo	—
Open source	No	No
Platforms	api, Web	Web
Free plan	Yes	No
Follow-up reminders	Yes	Yes
Email/calendar sync	No	Yes
Mobile apps	web	web
Import/export	Yes	Yes
Interaction history	Yes	Yes

Contact Book vs Nat

Contact Book

Nat