Eraser

Eraser is an AI-first diagramming and docs tool built for engineering teams who think in flowcharts, sequence diagrams, and cloud architecture maps. We rate it 84/100 — an excellent pick for software teams that want diagrams to live next to code rather than rotting inside Confluence.

What is Eraser?

Eraser is a web-based canvas + markdown notes app aimed squarely at developers, founded in 2021 by Shin Kim (formerly chief of staff to investor Elad Gil). The product launched out of stealth in November 2021 and crossed one million users not long after, then went deeper on AI in May 2023 with a free sidecar called DiagramGPT — that single tool now drives roughly 30% of all Eraser sign-ups according to its founder.

The pitch is simple: most engineering teams either fight Lucidchart, draw in Figma, or skip diagrams entirely. Eraser treats diagrams as code (a markdown-like syntax called diagram-as-code), pairs that with an AI that converts prose or codebase context into structured drawings, and ships a two-way GitHub integration so design docs can be reviewed in pull requests. Total disclosed funding is around $6.75M across seed and follow-on rounds.

Key Features of Eraser

• AI Diagrams: Type a description ("a microservice posting events to Kafka, consumed by a payments worker writing to Postgres") and Eraser generates a flowchart, sequence diagram, ERD, or cloud architecture diagram in under five seconds.
• Diagram-as-code: Every visual is also editable as plain-text markup, which means diagrams diff cleanly in Git and survive copy-paste between tools.
• Codebase-aware diagrams: The 2025 codebase mode reads a connected GitHub repository and produces architecture diagrams that update themselves as the code changes.
• 500+ tech icons: AWS, GCP, Azure, Kubernetes, and language logos are pre-loaded — no more PNG-hunting for an EKS icon.
• Real-time collaboration + comments: Multiple cursors, inline comments, and a markdown notes panel sit alongside every canvas.
• Integrations: Native embeds in Notion and Confluence, a VS Code extension, and a one-click GitHub commit flow for shipping diagrams as part of a repo.

What Users Say About Eraser

Sentiment on Product Hunt and Reddit is mostly positive but specific. The most upvoted theme is speed: developers consistently report producing a usable diagram in roughly a tenth of the time it would take in Lucidchart or draw.io, with case studies on Eraser's own site claiming 10× to 20× improvements. Diagram-as-code gets praise from engineers who already version-control their docs.

The recurring complaints are equally consistent. The mobile web app is functional for viewing but painful for editing, the AI sometimes invents component names that do not exist in the supplied context, and the diagram catalog is narrow — there is no native mind-map, Gantt, or BPMN type yet. A few Reddit threads in r/devops note that the free tier's 5-AI-diagram limit gets used up quickly when learning the tool.

Eraser Pricing

Plan	Price	Key Limits
Free	$0/month	3 files, 5 AI diagrams, 7-day version history, unlimited guests
Starter	$15/user/mo (annual) or $20 monthly	Unlimited files, 40 AI diagrams, 90-day history, private files, 20 custom icons
Business	$45/user/mo (annual) or $60 monthly	250 AI diagrams, unlimited history, SAML SSO, 100 custom icons, reference diagrams
Enterprise	Contact sales	Unlimited AI, flexible deployments, customer success manager, ACH/wire

The Starter plan is the sweet spot for indie developers and small teams; Business is priced where most engineering orgs will land thanks to SSO being gated to that tier.

Who Should Use Eraser?

Best for: Software engineers, staff/principal engineers writing RFCs, platform teams documenting service architectures, and any engineering org running "docs as code" with PR-based reviews.

Not ideal for: Project managers who need Gantt charts or mind maps, mobile-first users, or teams that want a general whiteboard for fully freeform brainstorming — tldraw or FigJam fit better there.

Pros and Cons

Pros:

• AI generation is genuinely fast and produces a sensible first draft on the first try.
• Diagram-as-code makes the format git-friendly and copy-paste portable.
• Deep GitHub integration — diagrams commit alongside code.
• 500+ technical icons cover most cloud and infra needs out of the box.
• Eraser explicitly states user data is not used to train its models.

Cons:

• Mobile experience is read-only in practice.
• Free-tier AI quota (5 diagrams) runs out quickly.
• Limited diagram catalog — no mind-map, Gantt, or BPMN.
• SAML SSO is gated to the $45/seat Business plan.

Alternatives to Eraser

Excalidraw is the open-source freeform whiteboard if you want everything to look hand-drawn and don't need AI. tldraw is the most ambitious infinite-canvas tool right now, with its own AI features. Mermaid (free, embedded in GitHub) is the no-cost diagram-as-code option for teams that don't need a UI. Eraser sits above all three in polish and engineering-team focus, but its closed-source core and per-seat pricing are real trade-offs.

Verdict: Is Eraser Worth It?

For an engineering team that writes design docs and ships them in pull requests, Eraser is one of the best paid bets in 2026 — the AI is accurate enough to save real time, and the diagram-as-code format means your team's diagrams won't decay into screenshots. Solo developers can stay on the Free plan or use the public DiagramGPT for one-off generations. Skip it if you need mind-maps, mobile editing, or a generalist whiteboard. Our final score: 84/100.

Frequently Asked Questions

Is Eraser free?

Yes, Eraser has a Free plan that includes 3 files and 5 AI-generated diagrams per user. Paid plans start at $15/user/month billed annually ($20 monthly).

What platforms does Eraser support?

Eraser is a web app — it runs in any modern browser. There is no dedicated desktop or native mobile app, but a VS Code extension lets you edit Eraser diagrams inside your IDE.

How does Eraser compare to Lucidchart?

Lucidchart is broader (mind-maps, Gantt charts, BPMN) and aimed at all knowledge workers. Eraser is narrower but faster for engineering teams: it has true diagram-as-code, GitHub-native commits, and AI generation that Lucidchart's general-purpose AI doesn't match for technical diagrams.

Is Eraser open source?

No, Eraser's core product is closed source. The company has open-sourced some smaller pieces, and DiagramGPT is free to use without an account at eraser.io/diagramgpt.

Does Eraser train AI on my diagrams?

No. Eraser states publicly that customer data is not used to train its AI models, and OpenAI (its underlying LLM provider) does not train on API traffic by default.

Who owns Eraser?

Eraser is an independent startup founded by Shin Kim in 2021, with roughly $6.75M in disclosed funding from seed-stage investors.