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14,448 startups · 29 programs

Boundary

Active · The programming language for AI

WebsiteYC profile

Why it ranks

How the rank works
11signal of 100 · rising 4
  • team of 10Team size · YC's directory+5.4
  • went through YCProgram · this site+4
  • hiringHiring · Titles (titles.fru.dev), YC+2

A sum of public facts, not a judgement and not investment advice.

Competitors

AIDirected EdgeShared: programming language, machine learningYC S09San FranciscoStartup →AIFlowbotShared: natural language, programmingYC S19New York CityStartup →AIThe Token CompanyShared: llm output, natural languageYC W26San FranciscoStartup →AI.txtShared: llm outputSeedcamp 2023Startup →DataAcquiredAppjetShared: programming language, code, buildingYC S07San FranciscoStartup →OtherAI21 LabsShared: natural languageStartup →
Companies closest to Boundary
Company
Directed EdgeShared: programming language, machine learningYC S09ActiveAI
FlowbotShared: natural language, programmingYC S19ActiveAI, Devtools
The Token CompanyShared: llm output, natural languageYC W26ActiveAI
.txtShared: llm outputSeedcamp 2023Not statedAI, Devtools
AppjetShared: programming language, code, buildingYC S07AcquiredData, Devtools
AI21 Labsnot in a program hereShared: natural languageElsewhereOther

Adjacent

OtherBriko RoboticsShared: programming language500 Global Lucha 7MexicoStartup →Developer toolsDaggerShared: programming language, codeYC W19San FranciscoStartup →AIDeepgramShared: programming language, buildingYC W16San FranciscoStartup →AIScheduling WizardShared: programming language, work, buildingYC W26WashingtonStartup →OtherLiarbirdShared: these problemMassChallenge Switzerland and UK 2026AustraliaStartup →
Companies next to Boundary
Company
Briko RoboticsShared: programming language500 Global Lucha 7Not statedOther
DaggerShared: programming language, codeYC W19ActiveDevtools
DeepgramShared: programming language, buildingYC W16ActiveAI, Devtools
Scheduling WizardShared: programming language, work, buildingYC W26ActiveAI
LiarbirdShared: these problemMassChallenge Switzerland and UK 2026Not statedOther

Also from W23 in AI

All of W23
AICosineFully Agentic SWEYC W23LondonStartup →AIDataSuiteDataset Management for AI TrainersYC W23New York CityStartup →AI1stCollabPerformance-Optimized Influencer Marketing at ScaleYC W23San FranciscoStartup →AI222the AI social facilitator for offline human to human interactionsYC W23New York CityStartup →AIAqueductCreate, edit, and share procedural material graphs.YC W23PittsburghStartup →AIAtmetoBuilding a frontier world model for powerYC W23Los AngelesStartup →
Company
CosineFully Agentic SWEteam of 12hiringActiveAI, Devtools
DataSuiteDataset Management for AI Trainersteam of 4ActiveAI, Devtools
1stCollabPerformance-Optimized Influencer Marketing at Scaleteam of 11hiringActiveAI
222the AI social facilitator for offline human to human interactionsteam of 28hiringActiveAI
AqueductCreate, edit, and share procedural material graphs.ActiveAI, Devtools
AtmetoBuilding a frontier world model for powerteam of 2ActiveAI

About Boundary

Boundary is building BAML -- a programming language to build AI agents. We used to code in assembly, and moved on to C. From C, we moved on to higher level languages like Python. Now we are going from Python to natural language. What does the code look like when 50% of the business decisions is decided by an AI agent / prompts? How do you test these AI components? We made BAML to address these problems. BAML helps has built-in tools to test, observe, and work with structured LLM outputs / tool calling natively in the language 10x faster. With BAML you can also instantly parallelize LLM Calls, or react to certain events or changes in your pipelines, without having to write any boilerplate. It's like using 'React' for AI. BAML code can used from any other language -- providing a standardized way to organize and declare any LLM or AI code.

YC batch
W23 · Winter 2023
Status, per YC
Active
Category
AI, Developer tools
Team size
10
Location
Seattle, WA, USA
Checked
6h ago

YC tags: Developer Tools, Generative AI, Machine Learning, AI

Changes seen

TagsOct 19, 2026

No longer tagged Artificial Intelligence.

Source ↗

Boundary in W23: 274 companies, 69% AI

Boundary: questions

Which YC batch was Boundary in?

Boundary was in Y Combinator's Winter 2023 batch (W23).

Is Boundary still active?

Y Combinator lists Boundary as active.

Where is Boundary based?

Boundary lists Seattle, WA, USA as its location on YC's directory.