AI / LLM

Test Your Prompts
Before Production Breaks

PromptLab gives you a testing framework for LLM prompts. Compare outputs across models, catch regressions, and ship with confidence.

Untested Prompts Are Technical Debt

You wouldn't ship code without tests. But most teams push prompt changes to production with nothing but a gut check and a prayer.

Multi-Model Testing

Run the same prompt against GPT-4o, Claude, Gemini, Llama, and more. See how each model handles your edge cases.

Regression Detection

Define expected outputs. PromptLab flags when a prompt change causes unexpected behavior across your test suite.

Cost Tracking

See token usage and estimated cost for every test run. Compare cost/quality tradeoffs between models.

Version History

Every prompt change is tracked with its test results. Roll back to any previous version instantly.

Template Library

Start from battle-tested templates for classification, extraction, summarization, code generation, and more.

CI/CD Ready

Run prompt tests in your pipeline. Fail the build if quality drops below your threshold.

See It in Action

Define a test, run it, compare results. Three commands.

# Define a prompt test
$ promptlab init sentiment-classifier
Created: sentiment-classifier/
  prompt.txt · tests.yaml · config.yaml

# Run tests across two models
$ promptlab test sentiment-classifier/ --models gpt-4o,claude-sonnet
Running 12 test cases across 2 models...

Model: gpt-4o
  Passed: 11/12 (91.7%)
  Failed: "sarcasm-edge-case" — expected: negative, got: positive
  Tokens: 3,841 · Cost: $0.019

Model: claude-sonnet
  Passed: 12/12 (100%)
  Tokens: 3,212 · Cost: $0.010

# Compare with previous version
$ promptlab diff sentiment-classifier/ --last
v2 vs v1: +1 pass (gpt-4o), 0 regressions
Cost delta: -$0.003/run (prompt shortened by 40 tokens)

Template Library

Don't start from scratch. Pick a template, customize it, test it.

Classification

Sentiment Analysis

Multi-class sentiment with confidence scores. Handles sarcasm, mixed sentiment, and multilingual input.

Extraction

Entity Extraction

Pull structured data from unstructured text. Names, dates, amounts, addresses with JSON output.

Generation

Code Generation

Generate functions with docstrings, type hints, and test cases. Python, TypeScript, Go templates included.

Summarization

Document Summary

Configurable length and style. Extractive, abstractive, and bullet-point formats with key-point highlighting.

Q&A

RAG Pipeline

Question-answering over retrieved context. Includes hallucination detection and source attribution prompts.

Agents

Tool-Use Agent

Agent prompts with function calling. Includes routing logic, error handling, and multi-step reasoning templates.

Free vs Pro

Free gives you a complete testing workflow. Pro adds scale and team features.

FeatureFreePro ($24)
Multi-model testingYesYes
Test suite definition (YAML)YesYes
Regression detectionYesYes
Cost trackingYesYes
Basic templates (3)YesYes
Version historyUp to 5Unlimited
Full template library (15+)Yes
Parallel test executionYes
HTML report generationYes
Custom evaluation functionsYes
CI/CD integration (GitHub Actions)Yes
Prompt optimization suggestionsYes
Priority supportYes

Ship prompts like you ship code

Test first. Measure always. One-time purchase, no subscription.