DeepGym

RL training environments with verifiable rewards for coding agents.

You give it model-generated code. It runs the code in a sandbox, checks it against a verifier, and hands back a score. That score plugs straight into TRL, verl, OpenRLHF, or whatever you're using for GRPO/DAPO/PPO.

Quick Start

pip install deepgym

from deepgym import DeepGym, load_environment

dg = DeepGym(mode='local')
env = load_environment('coin_change')

solution = '''
def coin_change(coins, amount):
    dp = [float('inf')] * (amount + 1)
    dp[0] = 0
    for coin in coins:
        for x in range(coin, amount + 1):
            dp[x] = min(dp[x], dp[x - coin] + 1)
    return dp[amount] if dp[amount] != float('inf') else -1
'''

result = dg.run(env, model_output=solution)
print(f'Score: {result.score}, Passed: {result.passed}')

How it works

prompt --> model --> DeepGym sandbox --> verifier --> score --> training loop
                        |                  |
                     Daytona /          JSON protocol:
                     local subprocess   score, passed, reward_components

Model writes code. DeepGym runs it. Verifier checks it. You get back a score and per-test-case breakdown showing exactly which tests passed and which didn't.

What's in the box

• 24 built-in coding environments (ship with pip install)
• 2,350+ importable benchmarks (HumanEval, MBPP, BigCodeBench, EvalPlus)
• Per-test-case reward traces (not just pass/fail -- you see which tests broke)
• Deterministic seeding (same input, same score, every time)
• Three runtime modes: local subprocess, self-hosted Daytona, cloud Daytona
• Drop-in reward functions for TRL, verl, OpenRLHF
• Batch scoring for GRPO (score N completions in parallel)
• Gymnasium-style API if you prefer reset/step/state

Usage

Score a single solution

from deepgym import DeepGym, load_environment

dg = DeepGym(mode='local')
env = load_environment('two_sum')

result = dg.run(env, model_output='def two_sum(nums, target): ...')
print(result.score, result.passed, result.reward_components)

Batch scoring for GRPO

solutions = [model.generate(prompt) for _ in range(8)]
batch = dg.run_batch(env, solutions, max_parallel=8)

scores = [r.score for r in batch.results]
# GRPO advantage: (r - mean) / std
mean = sum(scores) / len(scores)
std = (sum((s - mean) ** 2 for s in scores) / len(scores)) ** 0.5
advantages = [(s - mean) / (std + 1e-8) for s in scores]

Drop into TRL

from deepgym.integrations.trl import make_trl_reward_fn
from trl import GRPOTrainer

reward_fn = make_trl_reward_fn(env)
trainer = GRPOTrainer(model=model, reward_funcs=[reward_fn])
trainer.train()

Write your own verifier

from deepgym import DeepGym, Environment

dg = DeepGym(mode='local')
env = Environment(
    task='Write a function `add(a, b)` that returns the sum of two numbers.',
    verifier_code=(
        'import importlib.util, sys\n'
        'spec = importlib.util.spec_from_file_location("sol", solution_path)\n'
        'mod = importlib.util.module_from_spec(spec)\n'
        'spec.loader.exec_module(mod)\n'
        'return 1.0 if hasattr(mod, "add") and mod.add(2, 3) == 5 else 0.0\n'
    ),
)

result = dg.run(env, model_output='def add(a, b):\n    return a + b\n')

The verifier_code string becomes the body of a function that gets (solution_path, test_cases_path=None). Return a float, bool, or dict. The wrapper handles the rest.

Environments

Built-in (24, ship with pip install)

Coding (20):

• Array/String: reverse_string, palindrome_check, anagram_check, max_subarray, rotate_array, remove_duplicates, valid_parentheses
• Hash Map: group_anagrams, longest_consecutive, top_k_frequent
• DP: climbing_stairs, coin_change, longest_common_subsequence, house_robber
• Graph/Tree: binary_search, merge_intervals, level_order_traversal
• Practical: fizzbuzz, roman_to_integer, matrix_spiral

Computer-use (2): file_organizer, cli_task

Tool-use (2): api_request, data_pipeline

Load by name:

from deepgym import load_environment
env = load_environment('coin_change')

Importable benchmarks

Run the import scripts to pull in standard benchmarks:

python scripts/import_humaneval.py      # 164 problems
python scripts/import_evalplus.py       # HumanEval+ (80x more tests) + MBPP+
python scripts/import_mbpp.py           # 500 problems
python scripts/import_bigcodebench.py   # 1,140 problems

After import, they're available through load_environment().

Verifier protocol

Verifiers output JSON to stdout:

{
  "schema_version": "1.0",
  "score": 0.85,
  "passed": true,
  "details": "12/14 tests passed",
  "cases": [
    {"id": "test_0", "passed": true, "score": 1.0, "input_summary": "coins=[1,2,5] amount=11"},
    {"id": "test_1", "passed": false, "score": 0.0, "error": "expected 3, got -1"}
  ],
  "seed": 42
}

The cases field is the interesting part -- it tells you exactly which tests passed and failed, so your training loop gets a denser signal than just 0 or 1.

Simple verifiers that return a float or bool get auto-wrapped to this format.

Architecture

Training Framework (verl / OpenRLHF / TRL)
    |
    v
DeepGym (environments + verifiers + scoring)
    |
    v
Daytona sandbox / local subprocess

Three modes: local (subprocess, no deps, no isolation), daytona (real container isolation), auto (tries Daytona, falls back to local).

Local mode is fine for development. For anything shared or untrusted, use Daytona.

CLI

deepgym run --task task.md --verifier verifier.py --solution solution.py

# Dev mode
DEEPGYM_NO_AUTH=true deepgym serve --host 127.0.0.1 --port 8000 --allow-local-exec

# Production
DEEPGYM_API_KEY=your-key DAYTONA_API_KEY=your-key deepgym serve --port 8000

The server won't start without auth configured. Set DEEPGYM_API_KEY for production or DEEPGYM_NO_AUTH=true for local development. --allow-local-exec is required when running without Daytona.

Development

pip install -e ".[dev]"   # install with test deps
pytest                    # 227 tests
ruff check src/           # lint
ruff format src/          # format

Daytona setup

git clone https://github.com/daytonaio/daytona
docker compose -f docker/docker-compose.yaml up -d
# Set DAYTONA_API_URL and DAYTONA_API_KEY

Or use Daytona cloud: get a key from app.daytona.io.

License

MIT