Convertible Note vs SAFE for AI Startups: A Founder's Guide

A convertible note is debt that converts to equity and carries an interest rate and a maturity date. A SAFE is a lighter agreement for future equity with no interest and no maturity. Most early AI startups now raise on SAFEs because they are faster and cheaper to close, which is exactly why Y Combinator built the SAFE and uses it in its standard deal. In Brazil and LATAM the closest local instrument is the contrato de mútuo conversível, and the right structure usually depends on where your fundable entity sits.

The short version

If you are raising a pre-seed or seed round for an AI company, you will almost certainly be handed one of two documents: a convertible note or a SAFE. They rhyme, so founders often treat them as interchangeable. They are not.

A **convertible note** is a loan. It has an interest rate, a maturity date, and the legal weight of debt. It converts into equity later, usually at your next priced round.

A **SAFE** (Simple Agreement for Future Equity) is not a loan. It has no interest and no maturity date. It is a promise to give the investor equity in the future when a triggering event happens, most often your next priced round.

Both let you delay the hard question of what your company is worth today. They just carry very different amounts of baggage.

What a convertible note actually is

A convertible note is structured as debt on your cap table until it converts. That means three moving parts matter:

The maturity date is the part that bites. An AI startup burning capital on compute and talent can easily slip past 24 months without a priced round. A note that comes due creates a pressure point you do not want during a hard fundraising market.

• **Interest rate.** Typically a few percent per year. It accrues and usually converts into additional equity rather than being paid back in cash.
• **Maturity date.** A hard deadline, often 18 to 24 months out. If you have not raised a qualifying round by then, the note technically comes due. In practice investors renegotiate, but the leverage sits with them.
• **Discount and valuation cap.** The mechanics that reward the investor for taking early risk, by letting the note convert at a lower price than the new money pays.

What a SAFE actually is

The SAFE was introduced by Y Combinator in 2013 as a founder-friendly alternative to the convertible note. Its whole design goal was to strip out the debt features. No interest. No maturity date. No repayment risk hanging over the company.

Y Combinator later revised the instrument. The original SAFE was pre-money, and in 2018 Y Combinator moved to a **post-money SAFE**, which makes dilution far easier to calculate because the investor owns a fixed percentage after the SAFE money is counted. When someone hands you a SAFE today, ask whether it is pre-money or post-money, because the answer changes your ownership math.

A SAFE still uses a valuation cap, a discount, or both. What it removes is the ticking clock.

Convertible note versus SAFE, side by side

Here is the same comparison across the features that matter most.

• Legal nature: a convertible note is debt, a SAFE is not debt.
• Interest rate: a note carries one, a SAFE does not.
• Maturity date: a note has one, a SAFE does not.
• Repayment risk: a note can come due, a SAFE cannot.
• Speed and cost to close: a note is slower and needs more negotiation, a SAFE is faster and standardized.
• Valuation cap or discount: a note usually carries both, a SAFE can use a cap, a discount, or both.
• Standard form origin: notes come from various law firms, the SAFE came from Y Combinator in 2013.

Why AI startups lean toward SAFEs

AI companies tend to raise early, raise often, and spend fast. Three things make SAFEs the default in this world.

First, **speed**. A standardized SAFE can close in days with minimal legal spend. Every dollar you do not pay a lawyer to negotiate a note is a dollar that goes into models, data, or hiring.

Second, **no maturity pressure**. AI roadmaps are lumpy. A SAFE does not punish you for taking 26 months instead of 18 to reach your next priced round.

Third, **investor familiarity**. The people writing the earliest checks into AI, including accelerators and experienced angels, already default to SAFEs, so you spend less time explaining the paper.

The tradeoff worth naming: because a SAFE has no maturity and no interest, it gives the investor less downside protection. That is precisely why founders like it and why some later-stage or more conservative investors still prefer notes.

What the standard accelerator deals actually use

The clearest public benchmarks come from the two best known accelerators, and both publish their terms.

**Y Combinator's standard deal invests $500,000 in every company it accepts.** That total is split into two instruments: **$125,000 for 7 percent of the company on a post-money SAFE, plus $375,000 on an uncapped SAFE with a most-favored-nation (MFN) provision.** It is worth being precise here, because the $125,000 for 7 percent number gets quoted on its own, which understates the full deal. The $375,000 uncapped tranche converts on the terms of your next priced round.

**Techstars' standard deal is different.** Techstars invests **$20,000 for 6 percent of the company in common stock, plus an optional $100,000 convertible note.** So one of the two most influential accelerators in the world still uses a convertible note as part of its core offer. Notes are not obsolete. They are a tool, and serious investors still reach for them.

The takeaway is not that one instrument won. It is that the paper you sign should match your situation, not a blog post. For a deeper comparison of these programs, see our guide on YC vs Techstars vs the studio model.

The Brazil and LATAM reality

If your company is built for Brazil and LATAM, the US SAFE is not automatically enforceable the way it is in Delaware. The closest and most common local instrument is the **contrato de mútuo conversível**, a convertible loan contract that behaves much like a convertible note. It is debt that converts into equity on agreed triggers.

Brazil also modernized its startup framework with **Lei Complementar 182/2021**, the Marco Legal das Startups, which created clearer rules for how investors can put capital into a startup without being treated as full partners exposed to the company's liabilities. That framework made convertible-style investing more predictable, but it did not import the US SAFE wholesale into Brazilian law.

A common approach for cross-border AI startups is to hold the fundable entity, or a holding structure above it, in a jurisdiction where a US-style SAFE is enforceable, while operating locally in Brazil. To be clear, that is a pattern founders and investors often use, not legal advice. The exact instrument and entity structure should be confirmed with cross-border counsel before you sign anything, because getting the entity and the instrument to line up is where deals actually break.

How Avante thinks about it

Avante co-founds AI-native companies for Brazil and LATAM, so this question is not academic for us. We help founders pick the instrument that matches where their fundable entity sits and who is writing the check, rather than defaulting to whichever template showed up first.

Studio-built companies tend to reach the point of raising outside capital with cleaner cap tables and clearer paperwork, which is part of why the studio model has drawn attention as a way to de-risk the earliest stage. We keep our own results qualitative here on purpose, and point founders to the mechanics rather than to promises about outcomes.

Bottom line

Use a **SAFE** when you want speed, standard terms, and no debt overhang, which is the common case for an early AI raise. Consider a **convertible note** when an investor wants downside protection or when you are working inside a program, like Techstars, that uses one. If you are building for Brazil and LATAM, expect the **contrato de mútuo conversível** to be the local-language equivalent, and get the entity structure right before you argue about the cap.

Whichever you sign, read for two things above all: the valuation cap and, if it is a note, the maturity date. Those two numbers shape your next round more than any other clause in the document.

Frequently asked questions

What is the main difference between a convertible note and a SAFE?

A convertible note is debt. It carries an interest rate and a maturity date, and it converts into equity at your next priced round. A SAFE is not debt. It has no interest and no maturity date, and it is simply a promise of future equity when a triggering event happens. The practical difference is that a note can come due and create repayment pressure, while a SAFE cannot.

Do most AI startups use SAFEs or convertible notes?

Most early-stage AI startups raise on SAFEs because they are faster and cheaper to close and carry no maturity pressure, which suits the lumpy timelines of AI roadmaps. Convertible notes are still used, especially when an investor wants more downside protection or when a program uses one by default.

What instrument does Y Combinator use in its standard deal?

Y Combinator's standard deal invests $500,000 in every accepted company. That total is $125,000 for 7 percent of the company on a post-money SAFE, plus $375,000 on an uncapped SAFE with a most-favored-nation provision. The $125,000 for 7 percent figure is only one part of the deal, not the whole thing.

What does Techstars use, a SAFE or a convertible note?

Techstars' standard deal is $20,000 for 6 percent of the company in common stock, plus an optional $100,000 convertible note. So one of the most influential accelerators still uses a convertible note as part of its core offer, which shows notes remain a legitimate tool rather than an outdated one.

What is the equivalent of a SAFE in Brazil?

The closest and most common Brazilian instrument is the contrato de mútuo conversível, a convertible loan contract that behaves much like a convertible note. Brazil also modernized its framework with Lei Complementar 182/2021, the Marco Legal das Startups, though that law did not import the US SAFE wholesale. Many cross-border founders hold the fundable entity in a jurisdiction where a US-style SAFE is enforceable, but the exact structure should be confirmed with cross-border counsel.