Service — AI Coding

Code RLHF

Software engineers evaluate AI-generated code on correctness, security, readability, efficiency, and style. Specialist annotator pools by language. Automated unit test execution and security linting combined with expert human judgment — the most rigorous code preference dataset you can build.

5+
Evaluation dimensions per code pair — correctness, security, readability, efficiency, style
10
Programming languages with specialist annotator pools available
Auto+Human
Automated test execution and security linting alongside human judgment
5yr+
Minimum engineering experience required for code annotators — not generalists
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Correctness TestingSecurity ReviewCode ReadabilityAlgorithm EfficiencyStyle ConsistencyUnit Test ExecutionSAST AnalysisMulti-Language SupportCorrectness TestingSecurity ReviewCode ReadabilityAlgorithm EfficiencyStyle Consistency
What It Is

Code preference data built by engineers, not crowdworkers

Code RLHF is preference data specifically for training AI coding assistants and code generation models. It requires annotators who can actually run code, reason about edge cases, spot security vulnerabilities, and compare algorithmic efficiency — none of which a general-purpose annotator can do reliably.

When comparing two AI-generated Python functions, a software engineer asks: Does this actually work? What happens with empty input? Is the time complexity optimal? Are there SQL injection risks? Is the variable naming clear enough for a junior engineer to maintain? Would this pass a code review at a senior level? These are the questions that produce high-quality code preference data.

General-purpose RLHF annotators — who are excellent at evaluating prose quality — cannot reliably answer these questions. They tend to prefer code that looks clean superficially (well-spaced, with comments) over code that is correct and secure, and they cannot distinguish O(n) from O(n²) algorithms. Studies on code preference annotation with non-engineers show that annotators regularly reward incorrect solutions that run without syntax errors over correct but more complex solutions.

Our Code RLHF service uses experienced software engineers (5+ years, verified) as annotators. Each pair is evaluated on all five quality dimensions. Automated execution of the code against a test suite runs alongside human review — giving you both execution-verified correctness and human judgment on readability and style. Security linting (Bandit for Python, ESLint security rules for JS) runs automatically to flag vulnerabilities the human reviewer should investigate.

Why is code annotation uniquely difficult?
Code has multiple independent quality dimensions that don't correlate. A function can be syntactically correct but logically wrong. It can be correct and efficient but unreadable. It can be readable and efficient but have SQL injection vulnerabilities. High-quality code RLHF requires annotators who can evaluate all dimensions independently — and automated tools to catch what human review might miss (like off-by-one errors in edge cases or subtle timing vulnerabilities).
What is the RLAIF pre-scoring step for code?
Before human engineers review each pair, our automated pipeline: (1) executes both code snippets against a test suite (if test cases are available or generatable), (2) runs SAST (static analysis security testing) on both snippets, (3) measures cyclomatic complexity, (4) checks style conformance against a specified style guide. These automated signals are presented to the engineer as a structured pre-review summary — the engineer then validates, overrides, or extends these findings with their own judgment.
Code RLHF Quality Comparison
✗ RESPONSE A · REJECTED
✓ RESPONSE B · PREFERRED
● THREAD SAFE
● CORRECTNESS: 9.1/10
▼ CODE QUALITY COMPARISON
RESP ANEUTRALRESP B ▶
✓ 5,800 CODE PAIRS · IAA 0.82
Code Quality

Engineers evaluating AI-generated code

Software engineers with specialist pools by language judge AI code on correctness, security, readability, and efficiency. Automated unit test execution and security linting included.

Get a Free Audit →
Live Annotation Interface

Code RLHF Quality Comparison Tool

Senior engineers compare two AI-generated code solutions, evaluating correctness, edge case handling, readability, and security — selecting the preferred output for reward model training.

ConcaveLabel Studio — Code RLHF · Task: Implement rate limiter · Engineer: Arjun K.
Response A REJECTED
def rate_limit(requests, limit): count = 0 for r in requests: if count < limit: process(r) count += 1 # TODO: add time window
NO TIME WINDOW MISSING RESET NO THREAD SAFETY READABLE
Response B PREFERRED ✓
import time from threading import Lock class TokenBucketLimiter: def __init__(self, rate, per): self.rate = rate self.per = per self.tokens = rate self.last = time.time() self._lock = Lock() def allow(self) -> bool: with self._lock: now = time.time() delta = now - self.last self.tokens = min( self.rate, self.tokens + delta * self.rate / self.per ) self.last = now if self.tokens >= 1: self.tokens -= 1 return True return False
TOKEN BUCKET THREAD SAFE SMOOTH REFILL PRODUCTION READY
Evaluation Dimensions

Five dimensions, independently scored per pair

Each preference pair receives a score on all five dimensions so your reward model learns to distinguish between quality improvements in specific areas — not just overall "better."

Correctness
Does the code do what was asked? Handles edge cases (null, empty, large inputs, boundary values)? Verified by automated test execution + human logic review.
🔒
Security
SQL injection, XSS, CSRF, path traversal, insecure random, hardcoded secrets, input validation gaps. Automated SAST + senior engineer security review.
📖
Readability
Naming clarity, function decomposition, comment appropriateness, code structure. Would a mid-level engineer understand this without a walkthrough?
Efficiency
Time complexity (Big-O), space complexity, unnecessary database calls, redundant loops, missed vectorisation opportunities. Algorithm choice relative to input scale.
🎨
Style
Conforms to language idioms (Pythonic, idiomatic JS), consistent formatting, appropriate use of language features, follows the specified style guide (PEP8, Airbnb, Google).
Supported Languages

Specialist engineers by language and domain

We do not assign Python engineers to evaluate Go or Java code. Each language has a dedicated annotator pool with verified experience. Language-specific style guides, linting rules, and test execution environments are configured for each project.

Python
JavaScript
TypeScript
Java
Go
SQL
C++
Rust
Swift
Kotlin
Code RLHF Evaluation Pipeline — Per Pair
📥 Code pair received — both versions isolated in sandboxAuto
🧪 Test suite execution — correctness + edge cases verifiedAuto
🔍 SAST security scan (Bandit / ESLint security / Semgrep)Auto
📊 Complexity analysis — cyclomatic, time/space estimationAuto
👨‍💻 Senior engineer reviews all 5 dimensions with auto-scan contextHuman
📋 Structured rationale written — per-dimension scores + overall preferenceHuman
🔁 15% sample independently re-reviewed by second engineerQA
The Process

From code pair to verified preference data

01
Project Scoping & Rubric Design
We review your code use case: what language(s), what coding tasks (algorithms, API integrations, data processing, infrastructure as code?), what style guide, what security requirements, and what matters most for your model (correctness over style, or security over efficiency?). We design a weighted rubric for your specific use case and run a calibration session with engineer annotators before production begins. Minimum κ ≥ 0.68 on code preference tasks before production — harder than prose due to subjective style dimension.
Language selectionStyle guide configWeighted rubricEngineer calibration
02
Automated Pre-Analysis
Each code pair runs through our automated analysis pipeline: test execution in a sandboxed environment (Python sandbox, Node.js container, Java JVM — fully isolated), SAST security scanning, complexity metrics, and style linting. Results are structured as a pre-review summary for the engineer annotator. Pairs where automation detects a clear winner (e.g., one version fails all tests and the other passes) are flagged — engineer confirms or investigates further rather than starting from scratch.
Sandboxed executionSAST scanComplexity metricsStyle lint
03
Senior Engineer Review
A senior software engineer (5+ years, language-specialist) evaluates both versions with the automated summary in view. They score each version on all five dimensions (1–5), write a rationale explaining their preference with specific code-level observations ("Version A has an O(n²) nested loop that could be replaced by a hash set lookup; Version B correctly uses O(n) approach"), and flag any security or correctness concerns not caught by automation. Engineers are explicitly forbidden from defaulting to style preference when correctness or security is the distinguishing factor.
5+ year engineersPer-dimension scoringCode-level rationaleSecurity flag requirement
04
QA & Delivery
15% of pairs independently reviewed by a second engineer. Any pair where engineers disagree on overall preference is adjudicated by our ML-engineer lead. Delivery in JSONL format with chosen/rejected code, per-dimension scores, engineer rationale, automated scan results, and QA metadata. Compatible with TRL, AxolotI, and OpenRLHF. Full QA report with engineer agreement rates by dimension and language.
15% second-engineer reviewJSONL deliveryTRL / AxolotI compatiblePer-dimension agreement report
Pricing

Per-pair pricing,
language-based tiers

Code RLHF is priced per preference pair based on language, complexity of the coding task, and whether security review is included as a primary dimension.

Request a Scoped Quote →
Python / JS / general (Tier 1)₹400–700 / pair
Go / Rust / C++ / systems (Tier 2)₹600–1,000 / pair
Security-primary review (Tier 3)₹1,000–1,800 / pair
SQL / database / query pairs₹350–600 / pair
Minimum project size300 pairs
Free audit20 pairs / ₹0

Get 20 code pairs evaluated free

Send us 20 of your AI model's code output pairs. We will run them through our engineer review pipeline and return per-dimension scores, rationale, and a quality baseline — no cost, no commitment.