AI Coding Agents · pascaldekloe

colfer

Colfer is a code-generation tool that creates serialization/deserialization code from schema definitions, optimized for speed and binary size. It supports C, Go, Java, and JavaScript, with a straightforward compiler and public-domain license.

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Source: GitHub — github.com/pascaldekloe/colfer

758

GitHub stars

Forks

Java

Primary language

CC0-1.0

License (Requires review (not clearly OSI))

Key facts

Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.

Field	Value
Repository	pascaldekloe/colfer
Owner	pascaldekloe
Primary language	Java
License	CC0-1.0 — Requires review (not clearly OSI)
Stars	758
Forks	55
Open issues	10
Latest release	v1.8.1 (2020-06-18)
Last updated	2026-02-26
Source	https://github.com/pascaldekloe/colfer

What colfer is

Colfer generates marshalling/unmarshalling code from .colf schema files for cross-language binary serialization. Built-in size limits prevent memory bombs; framing supports streaming and concatenation. Protocol inspired by Protocol Buffers but positioned as faster and smaller.

Quickstart

Get the colfer source

Clone the repository and explore it locally.

terminalbash

1git clone https://github.com/pascaldekloe/colfer.git2cd colfer3# follow the project's README for install & configuration

Need it deployed, integrated, or customized instead? DEV.co ships production installs.

Best use cases

High-Performance Microservices Communication

Colfer's optimization for speed and compact binary output makes it suitable for low-latency inter-service messaging where payload size and serialization overhead directly impact throughput.

Cross-Platform Mobile & Backend Systems

Native code generation for Java, Go, C, and JavaScript allows unified schema definitions across Android apps, backend services, and Node.js frontends without language translation friction.

Streaming and Bulk Data Processing

Framed format supports safe concatenation and streaming; built-in memory limits prevent denial-of-service from malformed or oversized payloads in untrusted data sources.

Implementation considerations

Schema must be committed to version control; code generation is typically part of the build pipeline (Maven plugin available for Java).
Default size limits (16 MB payload, 64k list elements) are configurable per compile target but affect all generated code—verify suitability for your data volumes.
Field count is treated as schema version; add new fields only at the end for backward compatibility; deprecated fields should be renamed to discourage use.
Text validation (UTF-8 handling) is not enforced during marshalling/unmarshalling; Java and JavaScript replace unmappable chars with '?', C and Go pass through malformed sequences.
Compiler requires schema definitions in .colf format; prebuilt binaries or `go get` installation recommended to avoid adding Go toolchain dependency to build.

When to avoid it — and what to weigh

Enumerations Required — Colfer explicitly does not support enumerations. If your domain requires type-safe enum fields, this is a hard blocker.
Rust or Python as Primary Languages — Language support is limited to C, Go, Java, and JavaScript. Rust and Python are listed as TODO; community ports exist but lack official support.
Evolving Schema with Many Fields — Hard limit of 127 fields per struct and no enumeration support constrains schema evolution. Complex domain models may require restructuring.
Human-Readable Format Preferred — Colfer is binary-only. If debugging, logging, or human inspection of payloads is critical, consider text-based formats (JSON, YAML) or hybrid approaches.

License & commercial use

Colfer is released under CC0-1.0 (Creative Commons Zero v1.0 Universal), placing the software in the public domain. The format specification is free and unencumbered.

CC0-1.0 is a public-domain dedication with no restrictions on commercial use, modification, or distribution. No warranties are implied. This is not a traditional OSI-approved license but achieves similar permissiveness. Recommended to review your legal team's interpretation of public-domain software in your jurisdiction.

DEV.co evaluation signals

Editorial assessment — not user reviews. Directional, with an explicit confidence level.

Signal	Assessment
Maintenance	Active
Documentation	Adequate
License clarity	Clear
Deployment complexity	Low
DEV.co fit	Good
Assessment confidence	High

Security considerations

Colfer includes built-in protections: hardcoded size limits prevent memory exhaustion from untrusted input, framing prevents reading outside serial boundaries, marshaller cannot produce malformed output. Fuzz testing has not revealed vulnerabilities to date, but security assurances depend on implementation maturity. UTF-8 handling is lenient (replacement rather than rejection); validate text fields at application layer if strict encoding enforcement is required. Field count is not cryptographically signed; schema tampering is not detected.

Alternatives to consider

Protocol Buffers (protobuf)

Industry standard with broader ecosystem, official support for Rust/Python, more mature tooling. Colfer positions itself as faster and smaller but protobuf has stronger community, better documentation, and richer language support.

FlatBuffers

Zero-copy deserialization and similar performance goals. Broader language support and active Google backing. Better for scenarios requiring random access to nested structures without full deserialization.

MessagePack / CBOR

Simpler, language-agnostic binary formats without code generation. Easier to debug and inspect; useful if schema is fluid or if human inspection of payloads is needed. Trade-off: larger payload sizes.

Software development agency

Build on colfer with DEV.co software developers

If you're building cross-language microservices, mobile backends, or streaming systems where performance and payload size matter, download a prebuilt Colfer compiler and test with your schema. Review the benchmark wiki and security guarantees before committing to production use.

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colfer FAQ

Can I use Colfer with Python or Rust?

Official support is not available. Community ports exist (Gergely Bódi's Dart port, Karthik Kumar Viswanathan's Python alternative) but lack official maintenance. Rust and Python are listed as TODO on the roadmap.

What happens if I receive a payload larger than ColferSizeMax?

The unmarshaller will reject it and not allocate memory beyond the limit, preventing denial-of-service attacks. This is a core security guarantee of the format.

How do I handle schema evolution?

Add new fields only at the end of structs. Deprecated fields should be renamed (not removed) to discourage use. Field count acts as an implicit schema version. Breaking changes require careful migration planning.

Is Colfer suitable for REST APIs or only RPC-like messaging?

Colfer is binary and not human-readable, making it less suitable for direct HTTP/REST APIs unless clients and servers are both Colfer-aware. It is better suited for backend service-to-service communication, gRPC-like patterns, or embedded protocols.

Custom software development services

DEV.co is a software development agency delivering custom software development services to companies building on open source. Our software developers and web developers design, integrate, and ship production systems — spanning web development, APIs, AI, data, and cloud. If colfer is part of your ai coding agents roadmap, our team can implement, customize, migrate, and maintain it.

Evaluate Colfer for Your Serialization Needs

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