Jonathan Siegel
Angel Investor
San Francisco, United States
Jonathan Siegel is a seed investor in San Francisco focused on Software and SaaS. Jonathan Siegel is the Partner of Bass and Siegel. He previously worked at Earth Class Mail as a Chairman. Jonathan Siegel attended Brown University.
- Total investments:
- 18
- Last investment:
- Lead investor:
- 0%
Last updated:
For AI agents: llms.txt
Industries Jonathan Siegel invests in
Stages Jonathan Siegel invests in
Countries Jonathan Siegel invests in
Round sizes
Contacts
| Type | Contact | Validation |
|---|---|---|
| Work email | ||
| Personal email | ||
| Work phone | ||
| Personal phone | ||
| Socials |
Round size
- Seed
- $200k–$3.5M
- Pre-Seed
- $700k–$1.1M
Investment Focus
Industry
- Software 6 (33%)
- SaaS 5 (28%)
- Information Technology 5 (28%)
- Apps 3 (17%)
- Enterprise Software 3 (17%)
Stage
- Seed 12 (67%)
- Pre-Seed 3 (17%)
- Angel 1 (6%)
- Series A 1 (6%)
- Series B 1 (6%)
Country
- United States 14 (78%)
- Japan 1 (6%)
- Poland 1 (6%)
- United Kingdom 1 (6%)
Investments
| Company | Description | Round | Links |
|---|---|---|---|
| Arcjet helps developers protect their apps in just a few lines of code. Implement rate limiting, bot protection, email validation, and defense against common attacks. | $3.6M / Seed / Sep 10, 2024 | ||
| Sixty is the next generation social graph. Its AI-powered personal assistant expands the power of your network and handles the tedious but essential daily grind that can overwhelm your inbox, meetings, networking and sense of well-being. Sixty helps you spend less time at the keyboard and more time connecting with humans. | $3M / Seed / Jun 27, 2023 | ||
| PilotGo is a digital assistant for car workshops that handles what nobody likes: phone calls, notes, orders, and quotes. It learns from every conversation, order, and repair to automate repetitive tasks — so staff can focus on fixing cars, helping customers, and growing the business. - Phone calls and scheduling - Quoting and parts ordering -Repair management - Client relationship management | $932K / Seed / Sep 22, 2022 | ||
| PilotGo is a digital assistant for car workshops that handles what nobody likes: phone calls, notes, orders, and quotes. It learns from every conversation, order, and repair to automate repetitive tasks — so staff can focus on fixing cars, helping customers, and growing the business. - Phone calls and scheduling - Quoting and parts ordering -Repair management - Client relationship management | $1M / Pre-Seed / Sep 22, 2022 | ||
| Sign Time works on creating and running electronic contract services. They provide more than simply electronic contracts with their e-signatures. Order forms, waivers, contracts, employment agreements any approval that clients need to maintain on file can be signed with them. SignTime e-signature services go beyond electronic contracts. SignTimecan sign any approval that is needed to keep on file, such as order forms, waivers, contracts, and employment agreements. | $2.7M / Series B / Sep 20, 2022 | ||
| Build better products using AI-powered research | $1.1M / Pre-Seed / Jan 13, 2022 | ||
| Autify is an AI-focused company that offers software testing solutions to address the challenges associated with automation testing. The company's flagship product, Autify No Code, empowers anyone to create automated end-to-end tests for their applications. Additionally, Autify's new product, Zenes, aims to simplify the process ofcreating new software tests through AI, allowing customers to work directly with the company's AI agent to generate tests from product documents. | $10M / Series A / Oct 06, 2021 | ||
| Anzen is a management insurance and operations tool using real-time HRIS and SaaS integrations to identify and avoid management risks. The company was founded in 2020 and is headquartered in San Francisco, California, United States. | $700K / Pre-Seed / Jan 21, 2021 | ||
| Dark is holistic programming language, editor, and hosted infrastructure. | $3.5M / Seed / Jul 15, 2017 | ||
| Startup based in Pleasanton, CA in stealth mode. | Seed / Mar 29, 2016 | ||
| See all 18 investments → | |||
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FAQ
What does Jonathan Siegel invest in?
Jonathan Siegel invests primarily in Software, SaaS and Information Technology startups, most often at Seed and Pre-Seed stage. Most of the 18 investments tracked by Shizune back companies in United States. The Investment Focus section breaks down every industry, stage and country in the portfolio.
What round sizes does Jonathan Siegel invest in?
Jonathan Siegel typically joins rounds of $200k–$3.5M at Seed and $700k–$1.1M at Pre-Seed. These are whole funding-round sizes, not Jonathan Siegel's own check, which is rarely disclosed: the 10th–90th percentile of the confirmed public funding rounds Jonathan Siegel took part in.
How do I contact Jonathan Siegel?
Public channels for Jonathan Siegel include LinkedIn, X (Twitter) and the website linked on this profile. For a verified work email and phone number, create a free Shizune account — contact data is searched across 20+ sources and validated before delivery, so your outreach lands in the right inbox.
When did Jonathan Siegel last invest?
The most recent investment recorded for Jonathan Siegel closed in Sep 2024. Shizune tracks 18 investments in total for this profile, including round sizes, stages and portfolio companies, all sourced from confirmed public funding rounds and refreshed monthly.
Is Shizune's investor data accurate?
Yes — every stat on this profile is calculated from confirmed public funding rounds monitored across hundreds of sources since 2020. This profile was last refreshed in Oct 2026 and is updated monthly. Spotted something off? Use the “Suggest an edit” link near the top of the page.
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