See the back-and-forth.
Mutual Spark and initiative signals put the exchange in perspective. Are you both adding to the conversation?
SPARK · YOUR INITIATIVE · THEIR INITIATIVE YOUR CONVERSATION, WITH A LITTLE CLARITY
Feel the spark.
Read the room.
The moment before you hit send? That's where Chemistry comes in. Live signals for your X chats, right beside the words you're writing.
Early access · Desktop Chrome · Manual installation
Sign in with Google to connect. No token copying required.
YOUR WORDS. YOUR CHOICE.POWERED BY JEV ↗
A
AlexIllustrative conversation
•••Still laughing at your terrible coffee joke.
Bad jokes. Excellent company.
Okay, smooth. Coffee this weekend? ☕
Only if I get to see that smile again.↑
✧ chemistry HUD● LIVE
62/100
Mutual engagement
Your initiative68
Their initiative74
Flirt64
Pressure8
Illustrative values. Signals, not predictions.
✧ A second look. Still your voice.
NO COPYING & PASTINGYOUR DRAFT, IN CONTEXTYOU ALWAYS HIT SEND
LESS SECOND-GUESSING
A dashboard for the conversation.
Not a script for your personality.
Check the words before send.
See the flirt, reply hook, and pressure in your draft. Edit in your own voice, with a little more awareness.
FLIRT · REPLY HOOK · PRESSURENotice the boundaries.
Sexual expression and Intimacy Check help surface context. A signal never means consent. When evidence is unclear, we say so.
SEX · INTIMACY CHECK · BOUNDARYRESEARCH-INFORMED CONVERSATION DESIGN
Notice. Share.
Keep it mutual.
Three simple principles help you notice the exchange and choose your next words.
01 / Notice what matters.
Responsiveness means acknowledging what someone said and how they feel. Chemistry looks for specific understanding, rather than generic compliments.
“That interview sounds disappointing. Which part was hardest?”BENEFIT: SEE WHETHER YOUR REPLY ACTUALLY CONNECTS.
02 / Share a little, both ways.
Gradual, reciprocal self-disclosure can support closeness. Look for voluntary sharing of experiences and feelings, at a pace both people choose.
“I get nervous before interviews too. A short walk helps me.”BENEFIT: NOTICE MUTUAL OPENNESS WITHOUT FORCING DEPTH.
03 / Give them something to pick up.
A relevant follow-up shows attention. Chemistry checks for connected questions and contributions from both people, rather than counting questions.
“You mentioned painting earlier — how did your first class go?”BENEFIT: MAKE YOUR NEXT MESSAGE EASIER TO RESPOND TO.
Question-asking and liking · 2017 ↗ · Follow-up discussion ↗
These studies inform what we look for; they do not validate Chemistry’s model, numerical scores or dating outcomes. Research contexts differ from your chat. No formula reveals someone’s feelings or consent.
Try these principles in Playground ↗TRY IT · NO INSTALLATION OR SIGN-IN
Same conversation.
A different kind of reply.
Choose how Alex responds, then try a draft. Watch the signals change.
Scripted simulation with fictional adults and illustrative scores. No AI requests, real messages, or trial credits are used.
You & Alex FICTIONAL ADULTS
Changing a draft affects draft signals, not the conversation’s Spark.
MUTUAL SPARK—/100 · simulated
UNDERSTAND THE MOVEMENT
A pulse of the exchange.
Not a progress bar to romance.
↗ What can lift Spark?
Both people respond personally, return warmth, pick up each other’s jokes, and keep a playful or affectionate exchange going. Reciprocity matters more than sending more messages.
↘ What can lower Spark?
Replies become one-sided or purely practical, playful exchanges stop, or someone expresses discomfort. Older warm messages can also leave the analysis window as new messages arrive.
What does not earn points?
Message volume, waiting, scrolling, and unsent drafts do not directly add or subtract Spark. There are no fixed rewards or penalties. Jev reassesses the sent conversation when context changes.
↳Responds with understanding↔Both share personally↗Both keep it going♡Flirting reciprocated✓Invitation reciprocated
Independent evidence cues, not a mandatory ladder. The first three inform connection; flirting and invitations are optional context. Jev reassesses the current sent conversation. Sexual language and sending more messages do not earn points. Our conservative display ceilings and thresholds are product choices, not research findings. ≈ marks an uncertain estimate.
What happens when the heart reaches 100?
The model sees strong, sustained reciprocal connection with all three core cues supported. Friendly conversation can qualify without flirting or sexual content. This is a description of the exchange, not proof of attraction, a predicted outcome or consent. Nothing automatically unlocks.
Why can Sexual tone be high while Spark is low?
Sexual tone measures how explicit the sent language is, including one-sided remarks. It does not measure mutual willingness. Your unsent draft affects the draft indicators, not this bar. A sexual proposal followed by refusal can have high Sexual tone and low Spark.
Which messages count?
The HUD uses a bounded window of up to 40 loaded text messages, subject to text limits. While active, scrolling preserves that analysis window. New messages append when they can be linked to its last message. Use ↻ in the full HUD to explicitly replace the window with currently loaded text. Images and voice messages are not analyzed.
STAY IN THE CONVERSATION
Open your chat.
Keep being you.
Add Chemistry
Download the extension, install it in desktop Chrome, and sign in with Google.
Choose a conversation
Open X Chat, confirm the conversation is between adults, and click Start. Only the selected conversation is analyzed.
Write. Notice. Decide.
Loaded messages and your draft provide context. Signals update as you write. Nothing is sent to X on your behalf.
MORE CLARITY, YOUR WAY
Claim the launch signup gift.
Find your rhythm.
Free
$0
Register during the three-day launch offer to receive 10 conversation sessions and 200 live analyses. After the deadline, new registrations require a paid plan. Each successful session lasts 30 minutes.
Check signup availability ↗Advanced HUD
$9.90 / month
150 sessions and 8,000 live analyses per month. Real-time conversation signals and draft checks.
View plan details ↗One monthly plan. Both session and analysis limits apply; a single analysis updates multiple signals.
YOUR NEXT MESSAGE, WITH MORE CLARITY
Meet your new
chat companion.
↓ Download Chrome extensionVersion 0.1.14 · Early access ZIP · Google sign-in
Not yet listed on the Chrome Web Store.
Install in a few steps
- Download and unzip chemistry-hud.zip.
- Open
chrome://extensionsin Chrome and enable Developer mode. - Click Load unpacked and select the unzipped folder containing
manifest.json. - Open Chemistry’s settings and sign in with Google. Then open X Chat ↗.
Replace an older Chemistry installation first. Keep the unzipped folder on your computer.
GOOD QUESTIONS
A little more
context.
Is it ready to use after downloading?
You can install it immediately. Sign in with Google to connect your extension. The three-day signup offer grants 10 sessions and 200 analyses once per account. Both limits apply. After the deadline, new users need a paid plan; previously granted balances remain usable. Paid checkout is not yet live. The interactive demo is open to everyone.
What does Chemistry read?
After you start a conversation, it reads loaded text messages and your unsent draft in that X conversation. It does not access your entire account history or analyze images and voice messages.
Where does my chat text go?
Your selected context is transmitted over HTTPS to our Render-hosted service, then to TypeSafe/Jev for analysis. Our application does not write chat text to a database or application logs. Provider processing is subject to its own policies. Pause or close the HUD to stop new analysis.
Does a high score mean they like me?
No. Scores describe observable language and interaction patterns. They do not reveal feelings or predict dates, replies, sex, or consent. Uncertain Spark scores are marked ≈; other uncertain signals may be withheld.
Which platforms work?
The current extension supports desktop X/Twitter web chat. Other messaging platforms and mobile apps are not supported. X interface changes can affect message extraction.