Source: https://seerepo.com/compare/chroma-core/chroma/vs/unionlabs/union
Markdown source: https://seerepo.com/compare/chroma-core/chroma/vs/unionlabs/union.md
Description: chroma and union share 16 technologies: axum, sqlx-postgres, sqlx, Postgres, SQLite, Tokio, tower, Ratatui, crossterm, schemars, tracing, tracing-opentelemetry, github.com/rs/zerolog, OpenTelemetry, tracing-subscriber, and opentelemetry-otlp. Both are written in Rust.

# chroma vs union

chroma and union share 16 technologies: axum, sqlx-postgres, sqlx, Postgres, SQLite, Tokio, tower, Ratatui, crossterm, schemars, tracing, tracing-opentelemetry, github.com/rs/zerolog, OpenTelemetry, tracing-subscriber, and opentelemetry-otlp. Both are written in Rust.

- [chroma-core/chroma](https://seerepo.com/r/chroma-core/chroma): Search infrastructure for AI
- [unionlabs/union](https://seerepo.com/r/unionlabs/union): The trust-minimized, zero-knowledge bridging protocol, designed for censorship resistance, extremely high security, and usage in decentralized finance.

## What they share and what sets them apart

- In common: axum, sqlx-postgres, sqlx, Postgres, SQLite, Tokio, tower, Ratatui, crossterm, schemars, tracing, tracing-opentelemetry, github.com/rs/zerolog, OpenTelemetry, tracing-subscriber, opentelemetry-otlp
- Only in chroma: FastAPI, aws-sdk-s3, pgx, pq, s3, sqlx-sqlite, arrow, foyer, object_store, usearch, uvicorn, OpenAI, Rich, indicatif, dialoguer, utoipa-swagger-ui, gorm.io/gorm, pypika, sea-query, bcrypt, github.com/aws/aws-sdk-go-v2/credentials, hf-hub, tokenizers, onnxruntime, rmcp, parquet, tree-sitter-md, validator, Pydantic, jsonschema, k8s-openapi, opentelemetry-api, opentelemetry-exporter-otlp-proto-grpc, opentelemetry-instrumentation-fastapi, github.com/pingcap/log, go.uber.org/zap, google-cloud-googleapis, boto3, go.opentelemetry.io/otel, go.opentelemetry.io/otel/metric, github.com/aws/aws-sdk-go-v2, github.com/aws/aws-sdk-go-v2/config, go.opentelemetry.io/contrib/instrumentation/github.com/aws/aws-sdk-go-v2/otelaws, go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc, go.opentelemetry.io/otel/exporters/otlp/otlptrace, go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc, go.opentelemetry.io/otel/sdk, go.opentelemetry.io/otel/sdk/metric, go.opentelemetry.io/otel/trace, kube, kubernetes, psutil, @xenova/transformers, cohere-ai, ollama, Ajv, Hugging Face, together-ai
- Only in union: net/http, Gorilla, moka, wasmtime, Svelte, SvelteKit, Supabase, @effect/platform, console, ed25519-dalek, Tailwind CSS, tailwind-merge, rehype-stringify, remark, remark-parse, unified, vfile, @effect/opentelemetry

## Side by side

| | chroma | union |
|---|---|---|
| Size | 474,465 lines written, 886 code files | 468,416 lines written, 1,841 code files |
| Who writes it | 1.5% of its commits signed by AI. With Claude Code, Cursor, and Sweep | 0% of its commits signed by AI. With CodeRabbit |
| Activity | Last push November 7, 2026, 4,542 commits, 29,650 stars | Last push July 25, 2026, 13,299 commits, 73,725 stars |
| Tests | 345 test files. 31% of its code files have a test that imports them | 120 test files. 10.4% of its code files have a test that imports them |

- Size: Lines written by people and agents, without generated ones; code files, without tests.
- Who writes it: A commit counts as AI's when it carries its signature: a Co-Authored-By line, its author name or the merge of its branch.
- Activity: From GitHub and its history, on the day SeeRepo read it.
- Tests: The files that test the code, and the share of code files a test imports.

## Frequently asked questions

### Which is bigger, chroma or union?

chroma, with 474,465 lines written; union has 468,416.

The proof: [chroma-core/chroma's code at commit 1a3ac2c](https://github.com/chroma-core/chroma/tree/1a3ac2c7c623adbd03ed2508dc27b98cdf26016d)

### Which has more GitHub stars, chroma or union?

union, with 73,725 stars; chroma has 29,650.

The proof: [unionlabs/union on GitHub](https://github.com/unionlabs/union)

### Which has more tests, chroma or union?

chroma, with 345 test files; union has 120.

The proof: [chroma-core/chroma's code at commit 1a3ac2c](https://github.com/chroma-core/chroma/tree/1a3ac2c7c623adbd03ed2508dc27b98cdf26016d)

### Which was updated more recently, chroma or union?

chroma: its last push was on November 7, 2026, and union's on July 25, 2026.

The proof: [chroma-core/chroma's commits on GitHub](https://github.com/chroma-core/chroma/commits)

### Which has more commits signed by AI, chroma or union?

chroma: an AI signed 1.5% of its commits, with Claude Code, Cursor, and Sweep.

The proof: [the commits each tool signed in chroma-core/chroma](https://seerepo.com/r/chroma-core/chroma/ai)

## Sources

- chroma-core/chroma: Read on November 8, 2026, at commit 1a3ac2c (https://github.com/chroma-core/chroma/tree/1a3ac2c7c623adbd03ed2508dc27b98cdf26016d)
- unionlabs/union: Read on November 5, 2026, at commit 031785b (https://github.com/unionlabs/union/tree/031785bb6dc6b957c624e62bc64c184409c97d7b)

## What is your repo built with?

Any public repo, with no account: https://seerepo.com/r/owner/repo/built, with the owner and name it has on GitHub.