Email and newsletters decision
Superhuman
A competent developer can build a useful single‑user AI email assistant covering the core loop in about a week, but Superhuman's value also relies on broad integrations and brand/enterprise features that are costly to reproduce, so building is sensible for a narrow workflow but not a full replacement.
Visit website↗Open-source builds that already do this
Every project below is open source and already does this job today. Fork one, self-host it, or take the parts you need — the build prompt further down assumes an empty file, and this is the shortcut past that. Licences differ; check the one on each card before you ship.
What a replacement has to do
- Provide AI-assisted inbox triage and reply drafting for a single user account (connect mailbox, surface suggested replies, send and archive messages).
What it still won’t have
- Integrated Docs, Databases, and Go proactive assistant
- 800+ built-in integrations and two‑way sync with enterprise tools
- Grammarly-built writing features and brand‑level polish
- Enterprise security, SSO, and admin controls
What remains hard
- Brand trust
Trusted by 40M+ people and 50K+ organizations
- Integration maintenance
800+ integrations
First-year cost
Keep paying
Paying is—cheaper in year one.
On cash alone, building overtakes the subscription at 4 seats.
Money you would actually spend
Time you would spend
—
What you would spend
What we assumed
The verdict above measures whether you could build it. This one is only about money.
Runnable build prompt
Build a minimal AI-assisted email client (Node.js backend, Next.js React frontend, Postgres, Redis for job queue) that connects to Gmail via OAuth, indexes recent inbox messages, generates reply suggestions via the OpenAI API, displays suggestions in a small web UI, sends replies via the Gmail API, and supports basic snooze/label actions. In scope: Gmail OAuth and sync (read/send), message storage schema, LLM integration for reply suggestions, simple responsive UI to pick/edit/send suggestions, background job processing, logging, and end-to-end tests for auth, message fetch, generation, and send. Out of scope: multi-account team workspaces, enterprise SSO, full docs/databases product, and 800+ third‑party integrations. Include error handling for API failures, retries for transient errors, and unit & integration tests. Provide Docker Compose for local dev and a small deployment script for a single VPS.
How we checked
How the score was reached
- Partly verdict base52
- An open-source build was found+5
- 5 cited sources+3
- Price verified on pricing page+3
- 3/3 assessment runs agreed+4
- Evidence score67
The base comes from the verdict. Everything under it is a check that either happened or did not, and each one is a fact frozen in this record rather than a judgement made at render time — so the same evidence always produces the same number.
How scoring works →Cited sources · 5
Every page the run actually retrieved.
- official productSuperhuman homepage
- official pricingSuperhuman pricing
- official docsSuperhuman Docs
- open sourceFoundry376/Mailspring
- open sourcecloudflare/agentic-inbox
Integrity checks
What held up, and what did not.
